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fae7d834 |
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27-Feb-2024 |
Matthew Wilcox (Oracle) <willy@infradead.org> |
mm: add __dump_folio() Turn __dump_page() into a wrapper around __dump_folio(). Snapshot the page & folio into a stack variable so we don't hit BUG_ON() if an allocation is freed under us and what was a folio pointer becomes a pointer to a tail page. [willy@infradead.org: fix build issue] Link: https://lkml.kernel.org/r/ZeAKCyTn_xS3O9cE@casper.infradead.org [willy@infradead.org: fix __dump_folio] Link: https://lkml.kernel.org/r/ZeJJegP8zM7S9GTy@casper.infradead.org [willy@infradead.org: fix pointer confusion] Link: https://lkml.kernel.org/r/ZeYa00ixxC4k1ot-@casper.infradead.org [akpm@linux-foundation.org: s/printk/pr_warn/] Link: https://lkml.kernel.org/r/20240227192337.757313-5-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
cc25bbe1 |
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13-Feb-2024 |
Kinsey Ho <kinseyho@google.com> |
mm/mglru: improve struct lru_gen_mm_walk Rename max_seq to seq in struct lru_gen_mm_walk to keep consistent with struct lru_gen_mm_state. Note that seq is not always up to date with max_seq from lru_gen_folio. No functional changes. Link: https://lkml.kernel.org/r/20240214060538.3524462-5-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Donet Tom <donettom@linux.vnet.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
f6564fce |
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18-Jan-2024 |
Marco Elver <elver@google.com> |
mm, kmsan: fix infinite recursion due to RCU critical section Alexander Potapenko writes in [1]: "For every memory access in the code instrumented by KMSAN we call kmsan_get_metadata() to obtain the metadata for the memory being accessed. For virtual memory the metadata pointers are stored in the corresponding `struct page`, therefore we need to call virt_to_page() to get them. According to the comment in arch/x86/include/asm/page.h, virt_to_page(kaddr) returns a valid pointer iff virt_addr_valid(kaddr) is true, so KMSAN needs to call virt_addr_valid() as well. To avoid recursion, kmsan_get_metadata() must not call instrumented code, therefore ./arch/x86/include/asm/kmsan.h forks parts of arch/x86/mm/physaddr.c to check whether a virtual address is valid or not. But the introduction of rcu_read_lock() to pfn_valid() added instrumented RCU API calls to virt_to_page_or_null(), which is called by kmsan_get_metadata(), so there is an infinite recursion now. I do not think it is correct to stop that recursion by doing kmsan_enter_runtime()/kmsan_exit_runtime() in kmsan_get_metadata(): that would prevent instrumented functions called from within the runtime from tracking the shadow values, which might introduce false positives." Fix the issue by switching pfn_valid() to the _sched() variant of rcu_read_lock/unlock(), which does not require calling into RCU. Given the critical section in pfn_valid() is very small, this is a reasonable trade-off (with preemptible RCU). KMSAN further needs to be careful to suppress calls into the scheduler, which would be another source of recursion. This can be done by wrapping the call to pfn_valid() into preempt_disable/enable_no_resched(). The downside is that this sacrifices breaking scheduling guarantees; however, a kernel compiled with KMSAN has already given up any performance guarantees due to being heavily instrumented. Note, KMSAN code already disables tracing via Makefile, and since mmzone.h is included, it is not necessary to use the notrace variant, which is generally preferred in all other cases. Link: https://lkml.kernel.org/r/20240115184430.2710652-1-glider@google.com [1] Link: https://lkml.kernel.org/r/20240118110022.2538350-1-elver@google.com Fixes: 5ec8e8ea8b77 ("mm/sparsemem: fix race in accessing memory_section->usage") Signed-off-by: Marco Elver <elver@google.com> Reported-by: Alexander Potapenko <glider@google.com> Reported-by: syzbot+93a9e8a3dea8d6085e12@syzkaller.appspotmail.com Reviewed-by: Alexander Potapenko <glider@google.com> Tested-by: Alexander Potapenko <glider@google.com> Cc: Charan Teja Kalla <quic_charante@quicinc.com> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
5e0a760b |
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28-Dec-2023 |
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> |
mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER commit 23baf831a32c ("mm, treewide: redefine MAX_ORDER sanely") has changed the definition of MAX_ORDER to be inclusive. This has caused issues with code that was not yet upstream and depended on the previous definition. To draw attention to the altered meaning of the define, rename MAX_ORDER to MAX_PAGE_ORDER. Link: https://lkml.kernel.org/r/20231228144704.14033-2-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
fd377218 |
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28-Dec-2023 |
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> |
mm, treewide: introduce NR_PAGE_ORDERS NR_PAGE_ORDERS defines the number of page orders supported by the page allocator, ranging from 0 to MAX_ORDER, MAX_ORDER + 1 in total. NR_PAGE_ORDERS assists in defining arrays of page orders and allows for more natural iteration over them. [kirill.shutemov@linux.intel.com: fixup for kerneldoc warning] Link: https://lkml.kernel.org/r/20240101111512.7empzyifq7kxtzk3@box Link: https://lkml.kernel.org/r/20231228144704.14033-1-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
b805ab3c |
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28-Dec-2023 |
Li Zhijian <lizhijian@fujitsu.com> |
mm/vmstat: move pgdemote_* out of CONFIG_NUMA_BALANCING Demotion can work well without CONFIG_NUMA_BALANCING. But the commit 23e9f0138963 ("mm/vmstat: move pgdemote_* to per-node stats") wrongly hid it behind CONFIG_NUMA_BALANCING. Fix it by moving them out of CONFIG_NUMA_BALANCING. Link: https://lkml.kernel.org/r/20231229022651.3229174-1-lizhijian@fujitsu.com Fixes: 23e9f0138963 ("mm/vmstat: move pgdemote_* to per-node stats") Signed-off-by: Li Zhijian <lizhijian@fujitsu.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
745b13e6 |
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27-Dec-2023 |
Kinsey Ho <kinseyho@google.com> |
mm/mglru: remove CONFIG_MEMCG Remove CONFIG_MEMCG in a refactoring to improve code readability at the cost of a few bytes in struct lru_gen_folio per node when CONFIG_MEMCG=n. Link: https://lkml.kernel.org/r/20231227141205.2200125-4-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Co-developed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Tested-by: Donet Tom <donettom@linux.vnet.ibm.com> Acked-by: Yu Zhao <yuzhao@google.com> Cc: kernel test robot <lkp@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
61dd3f24 |
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27-Dec-2023 |
Kinsey Ho <kinseyho@google.com> |
mm/mglru: add CONFIG_LRU_GEN_WALKS_MMU Add CONFIG_LRU_GEN_WALKS_MMU such that if disabled, the code that walks page tables to promote pages into the youngest generation will not be built. Also improves code readability by adding two helper functions get_mm_state() and get_next_mm(). Link: https://lkml.kernel.org/r/20231227141205.2200125-3-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Co-developed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Tested-by: Donet Tom <donettom@linux.vnet.ibm.com> Acked-by: Yu Zhao <yuzhao@google.com> Cc: kernel test robot <lkp@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
5ec8e8ea |
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13-Oct-2023 |
Charan Teja Kalla <quic_charante@quicinc.com> |
mm/sparsemem: fix race in accessing memory_section->usage The below race is observed on a PFN which falls into the device memory region with the system memory configuration where PFN's are such that [ZONE_NORMAL ZONE_DEVICE ZONE_NORMAL]. Since normal zone start and end pfn contains the device memory PFN's as well, the compaction triggered will try on the device memory PFN's too though they end up in NOP(because pfn_to_online_page() returns NULL for ZONE_DEVICE memory sections). When from other core, the section mappings are being removed for the ZONE_DEVICE region, that the PFN in question belongs to, on which compaction is currently being operated is resulting into the kernel crash with CONFIG_SPASEMEM_VMEMAP enabled. The crash logs can be seen at [1]. compact_zone() memunmap_pages ------------- --------------- __pageblock_pfn_to_page ...... (a)pfn_valid(): valid_section()//return true (b)__remove_pages()-> sparse_remove_section()-> section_deactivate(): [Free the array ms->usage and set ms->usage = NULL] pfn_section_valid() [Access ms->usage which is NULL] NOTE: From the above it can be said that the race is reduced to between the pfn_valid()/pfn_section_valid() and the section deactivate with SPASEMEM_VMEMAP enabled. The commit b943f045a9af("mm/sparse: fix kernel crash with pfn_section_valid check") tried to address the same problem by clearing the SECTION_HAS_MEM_MAP with the expectation of valid_section() returns false thus ms->usage is not accessed. Fix this issue by the below steps: a) Clear SECTION_HAS_MEM_MAP before freeing the ->usage. b) RCU protected read side critical section will either return NULL when SECTION_HAS_MEM_MAP is cleared or can successfully access ->usage. c) Free the ->usage with kfree_rcu() and set ms->usage = NULL. No attempt will be made to access ->usage after this as the SECTION_HAS_MEM_MAP is cleared thus valid_section() return false. Thanks to David/Pavan for their inputs on this patch. [1] https://lore.kernel.org/linux-mm/994410bb-89aa-d987-1f50-f514903c55aa@quicinc.com/ On Snapdragon SoC, with the mentioned memory configuration of PFN's as [ZONE_NORMAL ZONE_DEVICE ZONE_NORMAL], we are able to see bunch of issues daily while testing on a device farm. For this particular issue below is the log. Though the below log is not directly pointing to the pfn_section_valid(){ ms->usage;}, when we loaded this dump on T32 lauterbach tool, it is pointing. [ 540.578056] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ 540.578068] Mem abort info: [ 540.578070] ESR = 0x0000000096000005 [ 540.578073] EC = 0x25: DABT (current EL), IL = 32 bits [ 540.578077] SET = 0, FnV = 0 [ 540.578080] EA = 0, S1PTW = 0 [ 540.578082] FSC = 0x05: level 1 translation fault [ 540.578085] Data abort info: [ 540.578086] ISV = 0, ISS = 0x00000005 [ 540.578088] CM = 0, WnR = 0 [ 540.579431] pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBSBTYPE=--) [ 540.579436] pc : __pageblock_pfn_to_page+0x6c/0x14c [ 540.579454] lr : compact_zone+0x994/0x1058 [ 540.579460] sp : ffffffc03579b510 [ 540.579463] x29: ffffffc03579b510 x28: 0000000000235800 x27:000000000000000c [ 540.579470] x26: 0000000000235c00 x25: 0000000000000068 x24:ffffffc03579b640 [ 540.579477] x23: 0000000000000001 x22: ffffffc03579b660 x21:0000000000000000 [ 540.579483] x20: 0000000000235bff x19: ffffffdebf7e3940 x18:ffffffdebf66d140 [ 540.579489] x17: 00000000739ba063 x16: 00000000739ba063 x15:00000000009f4bff [ 540.579495] x14: 0000008000000000 x13: 0000000000000000 x12:0000000000000001 [ 540.579501] x11: 0000000000000000 x10: 0000000000000000 x9 :ffffff897d2cd440 [ 540.579507] x8 : 0000000000000000 x7 : 0000000000000000 x6 :ffffffc03579b5b4 [ 540.579512] x5 : 0000000000027f25 x4 : ffffffc03579b5b8 x3 :0000000000000001 [ 540.579518] x2 : ffffffdebf7e3940 x1 : 0000000000235c00 x0 :0000000000235800 [ 540.579524] Call trace: [ 540.579527] __pageblock_pfn_to_page+0x6c/0x14c [ 540.579533] compact_zone+0x994/0x1058 [ 540.579536] try_to_compact_pages+0x128/0x378 [ 540.579540] __alloc_pages_direct_compact+0x80/0x2b0 [ 540.579544] __alloc_pages_slowpath+0x5c0/0xe10 [ 540.579547] __alloc_pages+0x250/0x2d0 [ 540.579550] __iommu_dma_alloc_noncontiguous+0x13c/0x3fc [ 540.579561] iommu_dma_alloc+0xa0/0x320 [ 540.579565] dma_alloc_attrs+0xd4/0x108 [quic_charante@quicinc.com: use kfree_rcu() in place of synchronize_rcu(), per David] Link: https://lkml.kernel.org/r/1698403778-20938-1-git-send-email-quic_charante@quicinc.com Link: https://lkml.kernel.org/r/1697202267-23600-1-git-send-email-quic_charante@quicinc.com Fixes: f46edbd1b151 ("mm/sparsemem: add helpers track active portions of a section at boot") Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Oscar Salvador <osalvador@suse.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
b5ba474f |
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30-Nov-2023 |
Nhat Pham <nphamcs@gmail.com> |
zswap: shrink zswap pool based on memory pressure Currently, we only shrink the zswap pool when the user-defined limit is hit. This means that if we set the limit too high, cold data that are unlikely to be used again will reside in the pool, wasting precious memory. It is hard to predict how much zswap space will be needed ahead of time, as this depends on the workload (specifically, on factors such as memory access patterns and compressibility of the memory pages). This patch implements a memcg- and NUMA-aware shrinker for zswap, that is initiated when there is memory pressure. The shrinker does not have any parameter that must be tuned by the user, and can be opted in or out on a per-memcg basis. Furthermore, to make it more robust for many workloads and prevent overshrinking (i.e evicting warm pages that might be refaulted into memory), we build in the following heuristics: * Estimate the number of warm pages residing in zswap, and attempt to protect this region of the zswap LRU. * Scale the number of freeable objects by an estimate of the memory saving factor. The better zswap compresses the data, the fewer pages we will evict to swap (as we will otherwise incur IO for relatively small memory saving). * During reclaim, if the shrinker encounters a page that is also being brought into memory, the shrinker will cautiously terminate its shrinking action, as this is a sign that it is touching the warmer region of the zswap LRU. As a proof of concept, we ran the following synthetic benchmark: build the linux kernel in a memory-limited cgroup, and allocate some cold data in tmpfs to see if the shrinker could write them out and improved the overall performance. Depending on the amount of cold data generated, we observe from 14% to 35% reduction in kernel CPU time used in the kernel builds. [nphamcs@gmail.com: check shrinker enablement early, use less costly stat flushing] Link: https://lkml.kernel.org/r/20231206194456.3234203-1-nphamcs@gmail.com Link: https://lkml.kernel.org/r/20231130194023.4102148-7-nphamcs@gmail.com Signed-off-by: Nhat Pham <nphamcs@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Chris Li <chrisl@kernel.org> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Seth Jennings <sjenning@redhat.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Chengming Zhou <chengming.zhou@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
23e9f013 |
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02-Nov-2023 |
Li Zhijian <lizhijian@fujitsu.com> |
mm/vmstat: move pgdemote_* to per-node stats Demotion will migrate pages across nodes. Previously, only the global demotion statistics were accounted for. Changed them to per-node statistics, making it easier to observe where demotion occurs on each node. This will help to identify which nodes are under pressure. This patch also make pgdemote_* behind CONFIG_NUMA_BALANCING, since demotion is not available for !CONFIG_NUMA_BALANCING With this patch, here is a sample where node0 node1 are DRAM, node3 is PMEM: Global stats: $ grep demote /proc/vmstat pgdemote_kswapd 254288 pgdemote_direct 113497 pgdemote_khugepaged 0 Per-node stats: $ grep demote /sys/devices/system/node/node0/vmstat # demotion source pgdemote_kswapd 68454 pgdemote_direct 83431 pgdemote_khugepaged 0 $ grep demote /sys/devices/system/node/node1/vmstat # demotion source pgdemote_kswapd 185834 pgdemote_direct 30066 pgdemote_khugepaged 0 $ grep demote /sys/devices/system/node/node3/vmstat # demotion target pgdemote_kswapd 0 pgdemote_direct 0 pgdemote_khugepaged 0 Link: https://lkml.kernel.org/r/20231103031450.1456523-1-lizhijian@fujitsu.com Signed-off-by: Li Zhijian <lizhijian@fujitsu.com> Acked-by: "Huang, Ying" <ying.huang@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
4376807b |
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07-Dec-2023 |
Yu Zhao <yuzhao@google.com> |
mm/mglru: reclaim offlined memcgs harder In the effort to reduce zombie memcgs [1], it was discovered that the memcg LRU doesn't apply enough pressure on offlined memcgs. Specifically, instead of rotating them to the tail of the current generation (MEMCG_LRU_TAIL) for a second attempt, it moves them to the next generation (MEMCG_LRU_YOUNG) after the first attempt. Not applying enough pressure on offlined memcgs can cause them to build up, and this can be particularly harmful to memory-constrained systems. On Pixel 8 Pro, launching apps for 50 cycles: Before After Change Zombie memcgs 45 35 -22% [1] https://lore.kernel.org/CABdmKX2M6koq4Q0Cmp_-=wbP0Qa190HdEGGaHfxNS05gAkUtPA@mail.gmail.com/ Link: https://lkml.kernel.org/r/20231208061407.2125867-4-yuzhao@google.com Fixes: e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists") Signed-off-by: Yu Zhao <yuzhao@google.com> Reported-by: T.J. Mercier <tjmercier@google.com> Tested-by: T.J. Mercier <tjmercier@google.com> Cc: Charan Teja Kalla <quic_charante@quicinc.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jaroslav Pulchart <jaroslav.pulchart@gooddata.com> Cc: Kairui Song <ryncsn@gmail.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
8aa42061 |
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07-Dec-2023 |
Yu Zhao <yuzhao@google.com> |
mm/mglru: respect min_ttl_ms with memcgs While investigating kswapd "consuming 100% CPU" [1] (also see "mm/mglru: try to stop at high watermarks"), it was discovered that the memcg LRU can breach the thrashing protection imposed by min_ttl_ms. Before the memcg LRU: kswapd() shrink_node_memcgs() mem_cgroup_iter() inc_max_seq() // always hit a different memcg lru_gen_age_node() mem_cgroup_iter() check the timestamp of the oldest generation After the memcg LRU: kswapd() shrink_many() restart: iterate the memcg LRU: inc_max_seq() // occasionally hit the same memcg if raced with lru_gen_rotate_memcg(): goto restart lru_gen_age_node() mem_cgroup_iter() check the timestamp of the oldest generation Specifically, when the restart happens in shrink_many(), it needs to stick with the (memcg LRU) generation it began with. In other words, it should neither re-read memcg_lru->seq nor age an lruvec of a different generation. Otherwise it can hit the same memcg multiple times without giving lru_gen_age_node() a chance to check the timestamp of that memcg's oldest generation (against min_ttl_ms). [1] https://lore.kernel.org/CAK8fFZ4DY+GtBA40Pm7Nn5xCHy+51w3sfxPqkqpqakSXYyX+Wg@mail.gmail.com/ Link: https://lkml.kernel.org/r/20231208061407.2125867-3-yuzhao@google.com Fixes: e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists") Signed-off-by: Yu Zhao <yuzhao@google.com> Tested-by: T.J. Mercier <tjmercier@google.com> Cc: Charan Teja Kalla <quic_charante@quicinc.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jaroslav Pulchart <jaroslav.pulchart@gooddata.com> Cc: Kairui Song <ryncsn@gmail.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
6ccdcb6d |
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15-Oct-2023 |
Huang Ying <ying.huang@intel.com> |
mm, pcp: reduce detecting time of consecutive high order page freeing In current PCP auto-tuning design, if the number of pages allocated is much more than that of pages freed on a CPU, the PCP high may become the maximal value even if the allocating/freeing depth is small, for example, in the sender of network workloads. If a CPU was used as sender originally, then it is used as receiver after context switching, we need to fill the whole PCP with maximal high before triggering PCP draining for consecutive high order freeing. This will hurt the performance of some network workloads. To solve the issue, in this patch, we will track the consecutive page freeing with a counter in stead of relying on PCP draining. So, we can detect consecutive page freeing much earlier. On a 2-socket Intel server with 128 logical CPU, we tested SCTP_STREAM_MANY test case of netperf test suite with 64-pair processes. With the patch, the network bandwidth improves 5.0%. This restores the performance drop caused by PCP auto-tuning. Link: https://lkml.kernel.org/r/20231016053002.756205-10-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Christoph Lameter <cl@linux.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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57c0419c |
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15-Oct-2023 |
Huang Ying <ying.huang@intel.com> |
mm, pcp: decrease PCP high if free pages < high watermark One target of PCP is to minimize pages in PCP if the system free pages is too few. To reach that target, when page reclaiming is active for the zone (ZONE_RECLAIM_ACTIVE), we will stop increasing PCP high in allocating path, decrease PCP high and free some pages in freeing path. But this may be too late because the background page reclaiming may introduce latency for some workloads. So, in this patch, during page allocation we will detect whether the number of free pages of the zone is below high watermark. If so, we will stop increasing PCP high in allocating path, decrease PCP high and free some pages in freeing path. With this, we can reduce the possibility of the premature background page reclaiming caused by too large PCP. The high watermark checking is done in allocating path to reduce the overhead in hotter freeing path. Link: https://lkml.kernel.org/r/20231016053002.756205-9-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Christoph Lameter <cl@linux.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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90b41691 |
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15-Oct-2023 |
Huang Ying <ying.huang@intel.com> |
mm: add framework for PCP high auto-tuning The page allocation performance requirements of different workloads are usually different. So, we need to tune PCP (per-CPU pageset) high to optimize the workload page allocation performance. Now, we have a system wide sysctl knob (percpu_pagelist_high_fraction) to tune PCP high by hand. But, it's hard to find out the best value by hand. And one global configuration may not work best for the different workloads that run on the same system. One solution to these issues is to tune PCP high of each CPU automatically. This patch adds the framework for PCP high auto-tuning. With it, pcp->high of each CPU will be changed automatically by tuning algorithm at runtime. The minimal high (pcp->high_min) is the original PCP high value calculated based on the low watermark pages. While the maximal high (pcp->high_max) is the PCP high value when percpu_pagelist_high_fraction sysctl knob is set to MIN_PERCPU_PAGELIST_HIGH_FRACTION. That is, the maximal pcp->high that can be set via sysctl knob by hand. It's possible that PCP high auto-tuning doesn't work well for some workloads. So, when PCP high is tuned by hand via the sysctl knob, the auto-tuning will be disabled. The PCP high set by hand will be used instead. This patch only adds the framework, so pcp->high will be set to pcp->high_min (original default) always. We will add actual auto-tuning algorithm in the following patches in the series. Link: https://lkml.kernel.org/r/20231016053002.756205-7-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Christoph Lameter <cl@linux.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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c0a24239 |
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15-Oct-2023 |
Huang Ying <ying.huang@intel.com> |
mm, page_alloc: scale the number of pages that are batch allocated When a task is allocating a large number of order-0 pages, it may acquire the zone->lock multiple times allocating pages in batches. This may unnecessarily contend on the zone lock when allocating very large number of pages. This patch adapts the size of the batch based on the recent pattern to scale the batch size for subsequent allocations. On a 2-socket Intel server with 224 logical CPU, we run 8 kbuild instances in parallel (each with `make -j 28`) in 8 cgroup. This simulates the kbuild server that is used by 0-Day kbuild service. With the patch, the cycles% of the spinlock contention (mostly for zone lock) decreases from 12.6% to 11.0% (with PCP size == 367). Link: https://lkml.kernel.org/r/20231016053002.756205-6-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Suggested-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Christoph Lameter <cl@linux.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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362d37a1 |
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15-Oct-2023 |
Huang Ying <ying.huang@intel.com> |
mm, pcp: reduce lock contention for draining high-order pages In commit f26b3fa04611 ("mm/page_alloc: limit number of high-order pages on PCP during bulk free"), the PCP (Per-CPU Pageset) will be drained when PCP is mostly used for high-order pages freeing to improve the cache-hot pages reusing between page allocating and freeing CPUs. On system with small per-CPU data cache slice, pages shouldn't be cached before draining to guarantee cache-hot. But on a system with large per-CPU data cache slice, some pages can be cached before draining to reduce zone lock contention. So, in this patch, instead of draining without any caching, "pcp->batch" pages will be cached in PCP before draining if the size of the per-CPU data cache slice is more than "3 * batch". In theory, if the size of per-CPU data cache slice is more than "2 * batch", we can reuse cache-hot pages between CPUs. But considering the other usage of cache (code, other data accessing, etc.), "3 * batch" is used. Note: "3 * batch" is chosen to make sure the optimization works on recent x86_64 server CPUs. If you want to increase it, please check whether it breaks the optimization. On a 2-socket Intel server with 128 logical CPU, with the patch, the network bandwidth of the UNIX (AF_UNIX) test case of lmbench test suite with 16-pair processes increase 70.5%. The cycles% of the spinlock contention (mostly for zone lock) decreases from 46.1% to 21.3%. The number of PCP draining for high order pages freeing (free_high) decreases 89.9%. The cache miss rate keeps 0.2%. Link: https://lkml.kernel.org/r/20231016053002.756205-4-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Christoph Lameter <cl@linux.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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ca71fe1a |
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15-Oct-2023 |
Huang Ying <ying.huang@intel.com> |
mm, pcp: avoid to drain PCP when process exit Patch series "mm: PCP high auto-tuning", v3. The page allocation performance requirements of different workloads are often different. So, we need to tune the PCP (Per-CPU Pageset) high on each CPU automatically to optimize the page allocation performance. The list of patches in series is as follows, [1/9] mm, pcp: avoid to drain PCP when process exit [2/9] cacheinfo: calculate per-CPU data cache size [3/9] mm, pcp: reduce lock contention for draining high-order pages [4/9] mm: restrict the pcp batch scale factor to avoid too long latency [5/9] mm, page_alloc: scale the number of pages that are batch allocated [6/9] mm: add framework for PCP high auto-tuning [7/9] mm: tune PCP high automatically [8/9] mm, pcp: decrease PCP high if free pages < high watermark [9/9] mm, pcp: reduce detecting time of consecutive high order page freeing Patch [1/9], [2/9], [3/9] optimize the PCP draining for consecutive high-order pages freeing. Patch [4/9], [5/9] optimize batch freeing and allocating. Patch [6/9], [7/9], [8/9] implement and optimize a PCP high auto-tuning method. Patch [9/9] optimize the PCP draining for consecutive high order page freeing based on PCP high auto-tuning. The test results for patches with performance impact are as follows, kbuild ====== On a 2-socket Intel server with 224 logical CPU, we run 8 kbuild instances in parallel (each with `make -j 28`) in 8 cgroup. This simulates the kbuild server that is used by 0-Day kbuild service. build time lock contend% free_high alloc_zone ---------- ---------- --------- ---------- base 100.0 14.0 100.0 100.0 patch1 99.5 12.8 19.5 95.6 patch3 99.4 12.6 7.1 95.6 patch5 98.6 11.0 8.1 97.1 patch7 95.1 0.5 2.8 15.6 patch9 95.0 1.0 8.8 20.0 The PCP draining optimization (patch [1/9], [3/9]) and PCP batch allocation optimization (patch [5/9]) reduces zone lock contention a little. The PCP high auto-tuning (patch [7/9], [9/9]) reduces build time visibly. Where the tuning target: the number of pages allocated from zone reduces greatly. So, the zone contention cycles% reduces greatly. With PCP tuning patches (patch [7/9], [9/9]), the average used memory during test increases up to 18.4% because more pages are cached in PCP. But at the end of the test, the number of the used memory decreases to the same level as that of the base patch. That is, the pages cached in PCP will be released to zone after not being used actively. netperf SCTP_STREAM_MANY ======================== On a 2-socket Intel server with 128 logical CPU, we tested SCTP_STREAM_MANY test case of netperf test suite with 64-pair processes. score lock contend% free_high alloc_zone cache miss rate% ----- ---------- --------- ---------- ---------------- base 100.0 2.1 100.0 100.0 1.3 patch1 99.4 2.1 99.4 99.4 1.3 patch3 106.4 1.3 13.3 106.3 1.3 patch5 106.0 1.2 13.2 105.9 1.3 patch7 103.4 1.9 6.7 90.3 7.6 patch9 108.6 1.3 13.7 108.6 1.3 The PCP draining optimization (patch [1/9]+[3/9]) improves performance. The PCP high auto-tuning (patch [7/9]) reduces performance a little because PCP draining cannot be triggered in time sometimes. So, the cache miss rate% increases. The further PCP draining optimization (patch [9/9]) based on PCP tuning restore the performance. lmbench3 UNIX (AF_UNIX) ======================= On a 2-socket Intel server with 128 logical CPU, we tested UNIX (AF_UNIX socket) test case of lmbench3 test suite with 16-pair processes. score lock contend% free_high alloc_zone cache miss rate% ----- ---------- --------- ---------- ---------------- base 100.0 51.4 100.0 100.0 0.2 patch1 116.8 46.1 69.5 104.3 0.2 patch3 199.1 21.3 7.0 104.9 0.2 patch5 200.0 20.8 7.1 106.9 0.3 patch7 191.6 19.9 6.8 103.8 2.8 patch9 193.4 21.7 7.0 104.7 2.1 The PCP draining optimization (patch [1/9], [3/9]) improves performance much. The PCP tuning (patch [7/9]) reduces performance a little because PCP draining cannot be triggered in time sometimes. The further PCP draining optimization (patch [9/9]) based on PCP tuning restores the performance partly. The patchset adds several fields in struct per_cpu_pages. The struct layout before/after the patchset is as follows, base ==== struct per_cpu_pages { spinlock_t lock; /* 0 4 */ int count; /* 4 4 */ int high; /* 8 4 */ int batch; /* 12 4 */ short int free_factor; /* 16 2 */ short int expire; /* 18 2 */ /* XXX 4 bytes hole, try to pack */ struct list_head lists[13]; /* 24 208 */ /* size: 256, cachelines: 4, members: 7 */ /* sum members: 228, holes: 1, sum holes: 4 */ /* padding: 24 */ } __attribute__((__aligned__(64))); patched ======= struct per_cpu_pages { spinlock_t lock; /* 0 4 */ int count; /* 4 4 */ int high; /* 8 4 */ int high_min; /* 12 4 */ int high_max; /* 16 4 */ int batch; /* 20 4 */ u8 flags; /* 24 1 */ u8 alloc_factor; /* 25 1 */ u8 expire; /* 26 1 */ /* XXX 1 byte hole, try to pack */ short int free_count; /* 28 2 */ /* XXX 2 bytes hole, try to pack */ struct list_head lists[13]; /* 32 208 */ /* size: 256, cachelines: 4, members: 11 */ /* sum members: 237, holes: 2, sum holes: 3 */ /* padding: 16 */ } __attribute__((__aligned__(64))); The size of the struct doesn't changed with the patchset. This patch (of 9): In commit f26b3fa04611 ("mm/page_alloc: limit number of high-order pages on PCP during bulk free"), the PCP (Per-CPU Pageset) will be drained when PCP is mostly used for high-order pages freeing to improve the cache-hot pages reusing between page allocation and freeing CPUs. But, the PCP draining mechanism may be triggered unexpectedly when process exits. With some customized trace point, it was found that PCP draining (free_high == true) was triggered with the order-1 page freeing with the following call stack, => free_unref_page_commit => free_unref_page => __mmdrop => exit_mm => do_exit => do_group_exit => __x64_sys_exit_group => do_syscall_64 Checking the source code, this is the page table PGD freeing (mm_free_pgd()). It's a order-1 page freeing if CONFIG_PAGE_TABLE_ISOLATION=y. Which is a common configuration for security. Just before that, page freeing with the following call stack was found, => free_unref_page_commit => free_unref_page_list => release_pages => tlb_batch_pages_flush => tlb_finish_mmu => exit_mmap => __mmput => exit_mm => do_exit => do_group_exit => __x64_sys_exit_group => do_syscall_64 So, when a process exits, - a large number of user pages of the process will be freed without page allocation, it's highly possible that pcp->free_factor becomes > 0. In fact, this is expected behavior to improve process exit performance. - after freeing all user pages, the PGD will be freed, which is a order-1 page freeing, PCP will be drained. All in all, when a process exits, it's high possible that the PCP will be drained. This is an unexpected behavior. To avoid this, in the patch, the PCP draining will only be triggered for 2 consecutive high-order page freeing. On a 2-socket Intel server with 224 logical CPU, we run 8 kbuild instances in parallel (each with `make -j 28`) in 8 cgroup. This simulates the kbuild server that is used by 0-Day kbuild service. With the patch, the cycles% of the spinlock contention (mostly for zone lock) decreases from 14.0% to 12.8% (with PCP size == 367). The number of PCP draining for high order pages freeing (free_high) decreases 80.5%. This helps network workload too for reduced zone lock contention. On a 2-socket Intel server with 128 logical CPU, with the patch, the network bandwidth of the UNIX (AF_UNIX) test case of lmbench test suite with 16-pair processes increase 16.8%. The cycles% of the spinlock contention (mostly for zone lock) decreases from 51.4% to 46.1%. The number of PCP draining for high order pages freeing (free_high) decreases 30.5%. The cache miss rate keeps 0.2%. Link: https://lkml.kernel.org/r/20231016053002.756205-1-ying.huang@intel.com Link: https://lkml.kernel.org/r/20231016053002.756205-2-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Christoph Lameter <cl@linux.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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3dfbb555 |
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14-Sep-2023 |
Vlastimil Babka <vbabka@suse.cz> |
mm, vmscan: remove ISOLATE_UNMAPPED This isolate_mode_t flag is effectively unused since 89f6c88a6ab4 ("mm: __isolate_lru_page_prepare() in isolate_migratepages_block()") as sc->may_unmap is now checked directly (and only node_reclaim has a mode that sets it to 0). The last remaining place is mm_vmscan_lru_isolate tracepoint for the isolate_mode parameter. That one was mainly used to indicate the active/inactive mode, which the trace-vmscan-postprocess.pl script consumed, but that got silently broken. After fixing the script by the previous patch, it does not need the isolate_mode anymore. So just remove the parameter and with that the whole ISOLATE_UNMAPPED flag. Link: https://lkml.kernel.org/r/20230914131637.12204-4-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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8f21912a |
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06-Jul-2023 |
Miaohe Lin <linmiaohe@huawei.com> |
mm: remove obsolete comment above struct per_cpu_pages Since commit 01b44456a7aa ("mm/page_alloc: replace local_lock with normal spinlock"), per_cpu_pages is protected by normal spinlock. Remove the obsolete comment as it's not that helpful. Link: https://lkml.kernel.org/r/20230706092441.1574950-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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1bc545bf |
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20-Jun-2023 |
Yosry Ahmed <yosryahmed@google.com> |
mm/vmscan: fix root proactive reclaim unthrottling unbalanced node When memory.reclaim was introduced, it became the first case where cgroup_reclaim() is true for the root cgroup. Johannes concluded [1] that for most cases this is okay, except for one case. Historically, kswapd would throttle reclaim on a node if a lot of pages marked for reclaim are under writeback (aka the node is congested). This occurred by setting LRUVEC_CONGESTED bit in lruvec->flags. The bit would be cleared when the node is balanced. Similarly, cgroup reclaim would set the same bit when an lruvec is congested, and clear it on the way out of reclaim (to throttle local reclaimers). Before the introduction of memory.reclaim, the root memcg was the only target of kswapd reclaim, and non-root memcgs were the only targets of cgroup reclaim, so they would never interfere. Using the same bit for both was fine. After memory.reclaim, it is possible for cgroup reclaim on the root cgroup to clear the bit set by kswapd. This would result in reclaim on the node to be unthrottled before the node is balanced. Fix this by introducing separate bits for cgroup-level and node-level congestion. kswapd can unthrottle an lruvec that is marked as congested by cgroup reclaim (as the entire node should no longer be congested), but not vice versa (to prevent premature unthrottling before the entire node is balanced). [1]https://lore.kernel.org/lkml/20230405200150.GA35884@cmpxchg.org/ Link: https://lkml.kernel.org/r/20230621023101.432780-1-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Reported-by: Johannes Weiner <hannes@cmpxchg.org> Closes: https://lore.kernel.org/lkml/20230405200150.GA35884@cmpxchg.org/ Cc: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeelb@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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28fb54f6 |
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13-Jun-2023 |
Vishal Moola (Oracle) <vishal.moola@gmail.com> |
mmzone: introduce folio_migratetype() Introduce folio_migratetype() as a folio equivalent for get_pageblock_migratetype(). This function intends to return the migratetype the folio is located in, hence the name choice. Link: https://lkml.kernel.org/r/20230614021312.34085-3-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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708ff491 |
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13-Jun-2023 |
Vishal Moola (Oracle) <vishal.moola@gmail.com> |
mmzone: introduce folio_is_zone_movable() Patch series "Replace is_longterm_pinnable_page()", v2. This patchset introduces some more helper functions for the folio conversions, and converts all callers of is_longterm_pinnable_page() to use folios. This patch (of 5): Introduce folio_is_zone_movable() to act as a folio equivalent for is_zone_movable_page(). This is to assist in later folio conversions. Link: https://lkml.kernel.org/r/20230614021312.34085-1-vishal.moola@gmail.com Link: https://lkml.kernel.org/r/20230614021312.34085-2-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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5c7e7a0d |
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22-May-2023 |
T.J. Alumbaugh <talumbau@google.com> |
mm: multi-gen LRU: cleanup lru_gen_soft_reclaim() lru_gen_soft_reclaim() gets the lruvec from the memcg and node ID to keep a cleaner interface on the caller side. Link: https://lkml.kernel.org/r/20230522112058.2965866-2-talumbau@google.com Signed-off-by: T.J. Alumbaugh <talumbau@google.com> Reviewed-by: Yuanchu Xie <yuanchu@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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e95d372c |
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16-May-2023 |
Kefeng Wang <wangkefeng.wang@huawei.com> |
mm: page_alloc: move sysctls into it own fils This moves all page alloc related sysctls to its own file, as part of the kernel/sysctl.c spring cleaning, also move some functions declarations from mm.h into internal.h. Link: https://lkml.kernel.org/r/20230516063821.121844-13-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Len Brown <len.brown@intel.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: Rafael J. Wysocki <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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dcdfdd40 |
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06-Jun-2023 |
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> |
mm: Add support for unaccepted memory UEFI Specification version 2.9 introduces the concept of memory acceptance. Some Virtual Machine platforms, such as Intel TDX or AMD SEV-SNP, require memory to be accepted before it can be used by the guest. Accepting happens via a protocol specific to the Virtual Machine platform. There are several ways the kernel can deal with unaccepted memory: 1. Accept all the memory during boot. It is easy to implement and it doesn't have runtime cost once the system is booted. The downside is very long boot time. Accept can be parallelized to multiple CPUs to keep it manageable (i.e. via DEFERRED_STRUCT_PAGE_INIT), but it tends to saturate memory bandwidth and does not scale beyond the point. 2. Accept a block of memory on the first use. It requires more infrastructure and changes in page allocator to make it work, but it provides good boot time. On-demand memory accept means latency spikes every time kernel steps onto a new memory block. The spikes will go away once workload data set size gets stabilized or all memory gets accepted. 3. Accept all memory in background. Introduce a thread (or multiple) that gets memory accepted proactively. It will minimize time the system experience latency spikes on memory allocation while keeping low boot time. This approach cannot function on its own. It is an extension of #2: background memory acceptance requires functional scheduler, but the page allocator may need to tap into unaccepted memory before that. The downside of the approach is that these threads also steal CPU cycles and memory bandwidth from the user's workload and may hurt user experience. Implement #1 and #2 for now. #2 is the default. Some workloads may want to use #1 with accept_memory=eager in kernel command line. #3 can be implemented later based on user's demands. Support of unaccepted memory requires a few changes in core-mm code: - memblock accepts memory on allocation. It serves early boot memory allocations and doesn't limit them to pre-accepted pool of memory. - page allocator accepts memory on the first allocation of the page. When kernel runs out of accepted memory, it accepts memory until the high watermark is reached. It helps to minimize fragmentation. EFI code will provide two helpers if the platform supports unaccepted memory: - accept_memory() makes a range of physical addresses accepted. - range_contains_unaccepted_memory() checks anything within the range of physical addresses requires acceptance. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mike Rapoport <rppt@linux.ibm.com> # memblock Link: https://lore.kernel.org/r/20230606142637.5171-2-kirill.shutemov@linux.intel.com
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7f63cf2d |
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13-Apr-2023 |
Kalesh Singh <kaleshsingh@google.com> |
mm: Multi-gen LRU: remove wait_event_killable() Android 14 and later default to MGLRU [1] and field telemetry showed occasional long tail latency (>100ms) in the reclaim path. Tracing revealed priority inversion in the reclaim path. In try_to_inc_max_seq(), when high priority tasks were blocked on wait_event_killable(), the preemption of the low priority task to call wake_up_all() caused those high priority tasks to wait longer than necessary. In general, this problem is not different from others of its kind, e.g., one caused by mutex_lock(). However, it is specific to MGLRU because it introduced the new wait queue lruvec->mm_state.wait. The purpose of this new wait queue is to avoid the thundering herd problem. If many direct reclaimers rush into try_to_inc_max_seq(), only one can succeed, i.e., the one to wake up the rest, and the rest who failed might cause premature OOM kills if they do not wait. So far there is no evidence supporting this scenario, based on how often the wait has been hit. And this begs the question how useful the wait queue is in practice. Based on Minchan's recommendation, which is in line with his commit 6d4675e60135 ("mm: don't be stuck to rmap lock on reclaim path") and the rest of the MGLRU code which also uses trylock when possible, remove the wait queue. [1] https://android-review.googlesource.com/q/I7ed7fbfd6ef9ce10053347528125dd98c39e50bf Link: https://lkml.kernel.org/r/20230413214326.2147568-1-kaleshsingh@google.com Fixes: bd74fdaea146 ("mm: multi-gen LRU: support page table walks") Signed-off-by: Kalesh Singh <kaleshsingh@google.com> Suggested-by: Minchan Kim <minchan@kernel.org> Reported-by: Wei Wang <wvw@google.com> Acked-by: Yu Zhao <yuzhao@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Cc: Oleksandr Natalenko <oleksandr@natalenko.name> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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62f31bd4 |
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26-Mar-2023 |
Mike Rapoport (IBM) <rppt@kernel.org> |
mm: move free_area_empty() to mm/internal.h The free_area_empty() helper is only used inside mm/ so move it there to reduce noise in include/linux/mmzone.h Link: https://lkml.kernel.org/r/20230326160215.2674531-1-rppt@kernel.org Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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3f6dac0f |
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20-Mar-2023 |
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> |
mm/page_alloc: make deferred page init free pages in MAX_ORDER blocks Normal page init path frees pages during the boot in MAX_ORDER chunks, but deferred page init path does it in pageblock blocks. Change deferred page init path to work in MAX_ORDER blocks. For cases when MAX_ORDER is larger than pageblock, set migrate type to MIGRATE_MOVABLE for all pageblocks covered by the page. Link: https://lkml.kernel.org/r/20230321002415.20843-1-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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5d671eb4 |
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19-Mar-2023 |
Mike Rapoport (IBM) <rppt@kernel.org> |
mm: move get_page_from_free_area() to mm/page_alloc.c The get_page_from_free_area() helper is only used in mm/page_alloc.c so move it there to reduce noise in include/linux/mmzone.h Link: https://lkml.kernel.org/r/20230319114214.2133332-1-rppt@kernel.org Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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23baf831 |
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15-Mar-2023 |
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> |
mm, treewide: redefine MAX_ORDER sanely MAX_ORDER currently defined as number of orders page allocator supports: user can ask buddy allocator for page order between 0 and MAX_ORDER-1. This definition is counter-intuitive and lead to number of bugs all over the kernel. Change the definition of MAX_ORDER to be inclusive: the range of orders user can ask from buddy allocator is 0..MAX_ORDER now. [kirill@shutemov.name: fix min() warning] Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box [akpm@linux-foundation.org: fix another min_t warning] [kirill@shutemov.name: fixups per Zi Yan] Link: https://lkml.kernel.org/r/20230316232144.b7ic4cif4kjiabws@box.shutemov.name [akpm@linux-foundation.org: fix underlining in docs] Link: https://lore.kernel.org/oe-kbuild-all/202303191025.VRCTk6mP-lkp@intel.com/ Link: https://lkml.kernel.org/r/20230315113133.11326-11-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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9a52b2f3 |
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13-Feb-2023 |
T.J. Alumbaugh <talumbau@google.com> |
mm: multi-gen LRU: clean up sysfs code This patch cleans up the sysfs code. Specifically, 1. use sysfs_emit(), 2. use __ATTR_RW(), and 3. constify multi-gen LRU struct attribute_group. Link: https://lkml.kernel.org/r/20230214035445.1250139-1-talumbau@google.com Signed-off-by: T.J. Alumbaugh <talumbau@google.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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44b8f8bf |
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19-Jan-2023 |
Jiaqi Yan <jiaqiyan@google.com> |
mm: memory-failure: add memory failure stats to sysfs Patch series "Introduce per NUMA node memory error statistics", v2. Background ========== In the RFC for Kernel Support of Memory Error Detection [1], one advantage of software-based scanning over hardware patrol scrubber is the ability to make statistics visible to system administrators. The statistics include 2 categories: * Memory error statistics, for example, how many memory error are encountered, how many of them are recovered by the kernel. Note these memory errors are non-fatal to kernel: during the machine check exception (MCE) handling kernel already classified MCE's severity to be unnecessary to panic (but either action required or optional). * Scanner statistics, for example how many times the scanner have fully scanned a NUMA node, how many errors are first detected by the scanner. The memory error statistics are useful to userspace and actually not specific to scanner detected memory errors, and are the focus of this patchset. Motivation ========== Memory error stats are important to userspace but insufficient in kernel today. Datacenter administrators can better monitor a machine's memory health with the visible stats. For example, while memory errors are inevitable on servers with 10+ TB memory, starting server maintenance when there are only 1~2 recovered memory errors could be overreacting; in cloud production environment maintenance usually means live migrate all the workload running on the server and this usually causes nontrivial disruption to the customer. Providing insight into the scope of memory errors on a system helps to determine the appropriate follow-up action. In addition, the kernel's existing memory error stats need to be standardized so that userspace can reliably count on their usefulness. Today kernel provides following memory error info to userspace, but they are not sufficient or have disadvantages: * HardwareCorrupted in /proc/meminfo: number of bytes poisoned in total, not per NUMA node stats though * ras:memory_failure_event: only available after explicitly enabled * /dev/mcelog provides many useful info about the MCEs, but doesn't capture how memory_failure recovered memory MCEs * kernel logs: userspace needs to process log text Exposing memory error stats is also a good start for the in-kernel memory error detector. Today the data source of memory error stats are either direct memory error consumption, or hardware patrol scrubber detection (either signaled as UCNA or SRAO). Once in-kernel memory scanner is implemented, it will be the main source as it is usually configured to scan memory DIMMs constantly and faster than hardware patrol scrubber. How Implemented =============== As Naoya pointed out [2], exposing memory error statistics to userspace is useful independent of software or hardware scanner. Therefore we implement the memory error statistics independent of the in-kernel memory error detector. It exposes the following per NUMA node memory error counters: /sys/devices/system/node/node${X}/memory_failure/total /sys/devices/system/node/node${X}/memory_failure/recovered /sys/devices/system/node/node${X}/memory_failure/ignored /sys/devices/system/node/node${X}/memory_failure/failed /sys/devices/system/node/node${X}/memory_failure/delayed These counters describe how many raw pages are poisoned and after the attempted recoveries by the kernel, their resolutions: how many are recovered, ignored, failed, or delayed respectively. This approach can be easier to extend for future use cases than /proc/meminfo, trace event, and log. The following math holds for the statistics: * total = recovered + ignored + failed + delayed These memory error stats are reset during machine boot. The 1st commit introduces these sysfs entries. The 2nd commit populates memory error stats every time memory_failure attempts memory error recovery. The 3rd commit adds documentations for introduced stats. [1] https://lore.kernel.org/linux-mm/7E670362-C29E-4626-B546-26530D54F937@gmail.com/T/#mc22959244f5388891c523882e61163c6e4d703af [2] https://lore.kernel.org/linux-mm/7E670362-C29E-4626-B546-26530D54F937@gmail.com/T/#m52d8d7a333d8536bd7ce74253298858b1c0c0ac6 This patch (of 3): Today kernel provides following memory error info to userspace, but each has its own disadvantage * HardwareCorrupted in /proc/meminfo: number of bytes poisoned in total, not per NUMA node stats though * ras:memory_failure_event: only available after explicitly enabled * /dev/mcelog provides many useful info about the MCEs, but doesn't capture how memory_failure recovered memory MCEs * kernel logs: userspace needs to process log text Exposes per NUMA node memory error stats as sysfs entries: /sys/devices/system/node/node${X}/memory_failure/total /sys/devices/system/node/node${X}/memory_failure/recovered /sys/devices/system/node/node${X}/memory_failure/ignored /sys/devices/system/node/node${X}/memory_failure/failed /sys/devices/system/node/node${X}/memory_failure/delayed These counters describe how many raw pages are poisoned and after the attempted recoveries by the kernel, their resolutions: how many are recovered, ignored, failed, or delayed respectively. The following math holds for the statistics: * total = recovered + ignored + failed + delayed Link: https://lkml.kernel.org/r/20230120034622.2698268-1-jiaqiyan@google.com Link: https://lkml.kernel.org/r/20230120034622.2698268-2-jiaqiyan@google.com Signed-off-by: Jiaqi Yan <jiaqiyan@google.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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36c7b4db |
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17-Jan-2023 |
T.J. Alumbaugh <talumbau@google.com> |
mm: multi-gen LRU: section for memcg LRU Move memcg LRU code into a dedicated section. Improve the design doc to outline its architecture. Link: https://lkml.kernel.org/r/20230118001827.1040870-5-talumbau@google.com Signed-off-by: T.J. Alumbaugh <talumbau@google.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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e4dde56c |
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21-Dec-2022 |
Yu Zhao <yuzhao@google.com> |
mm: multi-gen LRU: per-node lru_gen_folio lists For each node, memcgs are divided into two generations: the old and the young. For each generation, memcgs are randomly sharded into multiple bins to improve scalability. For each bin, an RCU hlist_nulls is virtually divided into three segments: the head, the tail and the default. An onlining memcg is added to the tail of a random bin in the old generation. The eviction starts at the head of a random bin in the old generation. The per-node memcg generation counter, whose reminder (mod 2) indexes the old generation, is incremented when all its bins become empty. There are four operations: 1. MEMCG_LRU_HEAD, which moves an memcg to the head of a random bin in its current generation (old or young) and updates its "seg" to "head"; 2. MEMCG_LRU_TAIL, which moves an memcg to the tail of a random bin in its current generation (old or young) and updates its "seg" to "tail"; 3. MEMCG_LRU_OLD, which moves an memcg to the head of a random bin in the old generation, updates its "gen" to "old" and resets its "seg" to "default"; 4. MEMCG_LRU_YOUNG, which moves an memcg to the tail of a random bin in the young generation, updates its "gen" to "young" and resets its "seg" to "default". The events that trigger the above operations are: 1. Exceeding the soft limit, which triggers MEMCG_LRU_HEAD; 2. The first attempt to reclaim an memcg below low, which triggers MEMCG_LRU_TAIL; 3. The first attempt to reclaim an memcg below reclaimable size threshold, which triggers MEMCG_LRU_TAIL; 4. The second attempt to reclaim an memcg below reclaimable size threshold, which triggers MEMCG_LRU_YOUNG; 5. Attempting to reclaim an memcg below min, which triggers MEMCG_LRU_YOUNG; 6. Finishing the aging on the eviction path, which triggers MEMCG_LRU_YOUNG; 7. Offlining an memcg, which triggers MEMCG_LRU_OLD. Note that memcg LRU only applies to global reclaim, and the round-robin incrementing of their max_seq counters ensures the eventual fairness to all eligible memcgs. For memcg reclaim, it still relies on mem_cgroup_iter(). Link: https://lkml.kernel.org/r/20221222041905.2431096-7-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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6df1b221 |
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21-Dec-2022 |
Yu Zhao <yuzhao@google.com> |
mm: multi-gen LRU: rename lrugen->lists[] to lrugen->folios[] lru_gen_folio will be chained into per-node lists by the coming lrugen->list. Link: https://lkml.kernel.org/r/20221222041905.2431096-3-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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391655fe |
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21-Dec-2022 |
Yu Zhao <yuzhao@google.com> |
mm: multi-gen LRU: rename lru_gen_struct to lru_gen_folio Patch series "mm: multi-gen LRU: memcg LRU", v3. Overview ======== An memcg LRU is a per-node LRU of memcgs. It is also an LRU of LRUs, since each node and memcg combination has an LRU of folios (see mem_cgroup_lruvec()). Its goal is to improve the scalability of global reclaim, which is critical to system-wide memory overcommit in data centers. Note that memcg reclaim is currently out of scope. Its memory bloat is a pointer to each lruvec and negligible to each pglist_data. In terms of traversing memcgs during global reclaim, it improves the best-case complexity from O(n) to O(1) and does not affect the worst-case complexity O(n). Therefore, on average, it has a sublinear complexity in contrast to the current linear complexity. The basic structure of an memcg LRU can be understood by an analogy to the active/inactive LRU (of folios): 1. It has the young and the old (generations), i.e., the counterparts to the active and the inactive; 2. The increment of max_seq triggers promotion, i.e., the counterpart to activation; 3. Other events trigger similar operations, e.g., offlining an memcg triggers demotion, i.e., the counterpart to deactivation. In terms of global reclaim, it has two distinct features: 1. Sharding, which allows each thread to start at a random memcg (in the old generation) and improves parallelism; 2. Eventual fairness, which allows direct reclaim to bail out at will and reduces latency without affecting fairness over some time. The commit message in patch 6 details the workflow: https://lore.kernel.org/r/20221222041905.2431096-7-yuzhao@google.com/ The following is a simple test to quickly verify its effectiveness. Test design: 1. Create multiple memcgs. 2. Each memcg contains a job (fio). 3. All jobs access the same amount of memory randomly. 4. The system does not experience global memory pressure. 5. Periodically write to the root memory.reclaim. Desired outcome: 1. All memcgs have similar pgsteal counts, i.e., stddev(pgsteal) over mean(pgsteal) is close to 0%. 2. The total pgsteal is close to the total requested through memory.reclaim, i.e., sum(pgsteal) over sum(requested) is close to 100%. Actual outcome [1]: MGLRU off MGLRU on stddev(pgsteal) / mean(pgsteal) 75% 20% sum(pgsteal) / sum(requested) 425% 95% #################################################################### MEMCGS=128 for ((memcg = 0; memcg < $MEMCGS; memcg++)); do mkdir /sys/fs/cgroup/memcg$memcg done start() { echo $BASHPID > /sys/fs/cgroup/memcg$memcg/cgroup.procs fio -name=memcg$memcg --numjobs=1 --ioengine=mmap \ --filename=/dev/zero --size=1920M --rw=randrw \ --rate=64m,64m --random_distribution=random \ --fadvise_hint=0 --time_based --runtime=10h \ --group_reporting --minimal } for ((memcg = 0; memcg < $MEMCGS; memcg++)); do start & done sleep 600 for ((i = 0; i < 600; i++)); do echo 256m >/sys/fs/cgroup/memory.reclaim sleep 6 done for ((memcg = 0; memcg < $MEMCGS; memcg++)); do grep "pgsteal " /sys/fs/cgroup/memcg$memcg/memory.stat done #################################################################### [1]: This was obtained from running the above script (touches less than 256GB memory) on an EPYC 7B13 with 512GB DRAM for over an hour. This patch (of 8): The new name lru_gen_folio will be more distinct from the coming lru_gen_memcg. Link: https://lkml.kernel.org/r/20221222041905.2431096-1-yuzhao@google.com Link: https://lkml.kernel.org/r/20221222041905.2431096-2-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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c7cdf94e |
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07-Dec-2022 |
Wang Yong <yongw.kernel@gmail.com> |
mm: fix typo in struct pglist_data code comment change "stat" to "start". Link: https://lkml.kernel.org/r/20221207074011.GA151242@cloud Fixes: c959924b0dc5 ("memory tiering: adjust hot threshold automatically") Signed-off-by: Wang Yong <yongw.kernel@gmail.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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49580e69 |
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21-Oct-2022 |
Logan Gunthorpe <logang@deltatee.com> |
block: add check when merging zone device pages Consecutive zone device pages should not be merged into the same sgl or bvec segment with other types of pages or if they belong to different pgmaps. Otherwise getting the pgmap of a given segment is not possible without scanning the entire segment. This helper returns true either if both pages are not zone device pages or both pages are zone device pages with the same pgmap. Add a helper to determine if zone device pages are mergeable and use this helper in page_is_mergeable(). Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Link: https://lore.kernel.org/r/20221021174116.7200-5-logang@deltatee.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
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30e3b5d7 |
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16-Sep-2022 |
Miaohe Lin <linmiaohe@huawei.com> |
mm: remove obsolete pgdat_is_empty() There's no caller. Remove it. Link: https://lkml.kernel.org/r/20220916072257.9639-8-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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638a9ae9 |
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16-Sep-2022 |
Miaohe Lin <linmiaohe@huawei.com> |
mm: remove obsolete macro NR_PCP_ORDER_MASK and NR_PCP_ORDER_WIDTH Since commit 8b10b465d0e1 ("mm/page_alloc: free pages in a single pass during bulk free"), they're not used anymore. Remove them. Link: https://lkml.kernel.org/r/20220916072257.9639-4-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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e6ad640b |
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26-Aug-2022 |
Shakeel Butt <shakeelb@google.com> |
mm: deduplicate cacheline padding code There are three users (mmzone.h, memcontrol.h, page_counter.h) using similar code for forcing cacheline padding between fields of different structures. Dedup that code. Link: https://lkml.kernel.org/r/20220826230642.566725-1-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Suggested-by: Feng Tang <feng.tang@intel.com> Reviewed-by: Feng Tang <feng.tang@intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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7766cf7a |
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18-Aug-2022 |
Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> |
mm/demotion: add pg_data_t member to track node memory tier details Also update different helpes to use NODE_DATA()->memtier. Since node specific memtier can change based on the reassignment of NUMA node to a different memory tiers, accessing NODE_DATA()->memtier needs to happen under an rcu read lock or memory_tier_lock. Link: https://lkml.kernel.org/r/20220818131042.113280-7-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Acked-by: Wei Xu <weixugc@google.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Bharata B Rao <bharata@amd.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hesham Almatary <hesham.almatary@huawei.com> Cc: Jagdish Gediya <jvgediya.oss@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tim Chen <tim.c.chen@intel.com> Cc: Yang Shi <shy828301@gmail.com> Cc: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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1332a809 |
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18-Sep-2022 |
Yu Zhao <yuzhao@google.com> |
mm: multi-gen LRU: thrashing prevention Add /sys/kernel/mm/lru_gen/min_ttl_ms for thrashing prevention, as requested by many desktop users [1]. When set to value N, it prevents the working set of N milliseconds from getting evicted. The OOM killer is triggered if this working set cannot be kept in memory. Based on the average human detectable lag (~100ms), N=1000 usually eliminates intolerable lags due to thrashing. Larger values like N=3000 make lags less noticeable at the risk of premature OOM kills. Compared with the size-based approach [2], this time-based approach has the following advantages: 1. It is easier to configure because it is agnostic to applications and memory sizes. 2. It is more reliable because it is directly wired to the OOM killer. [1] https://lore.kernel.org/r/Ydza%2FzXKY9ATRoh6@google.com/ [2] https://lore.kernel.org/r/20101028191523.GA14972@google.com/ Link: https://lkml.kernel.org/r/20220918080010.2920238-12-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Barry Song <baohua@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
354ed597 |
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18-Sep-2022 |
Yu Zhao <yuzhao@google.com> |
mm: multi-gen LRU: kill switch Add /sys/kernel/mm/lru_gen/enabled as a kill switch. Components that can be disabled include: 0x0001: the multi-gen LRU core 0x0002: walking page table, when arch_has_hw_pte_young() returns true 0x0004: clearing the accessed bit in non-leaf PMD entries, when CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG=y [yYnN]: apply to all the components above E.g., echo y >/sys/kernel/mm/lru_gen/enabled cat /sys/kernel/mm/lru_gen/enabled 0x0007 echo 5 >/sys/kernel/mm/lru_gen/enabled cat /sys/kernel/mm/lru_gen/enabled 0x0005 NB: the page table walks happen on the scale of seconds under heavy memory pressure, in which case the mmap_lock contention is a lesser concern, compared with the LRU lock contention and the I/O congestion. So far the only well-known case of the mmap_lock contention happens on Android, due to Scudo [1] which allocates several thousand VMAs for merely a few hundred MBs. The SPF and the Maple Tree also have provided their own assessments [2][3]. However, if walking page tables does worsen the mmap_lock contention, the kill switch can be used to disable it. In this case the multi-gen LRU will suffer a minor performance degradation, as shown previously. Clearing the accessed bit in non-leaf PMD entries can also be disabled, since this behavior was not tested on x86 varieties other than Intel and AMD. [1] https://source.android.com/devices/tech/debug/scudo [2] https://lore.kernel.org/r/20220128131006.67712-1-michel@lespinasse.org/ [3] https://lore.kernel.org/r/20220426150616.3937571-1-Liam.Howlett@oracle.com/ Link: https://lkml.kernel.org/r/20220918080010.2920238-11-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Barry Song <baohua@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
bd74fdae |
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18-Sep-2022 |
Yu Zhao <yuzhao@google.com> |
mm: multi-gen LRU: support page table walks To further exploit spatial locality, the aging prefers to walk page tables to search for young PTEs and promote hot pages. A kill switch will be added in the next patch to disable this behavior. When disabled, the aging relies on the rmap only. NB: this behavior has nothing similar with the page table scanning in the 2.4 kernel [1], which searches page tables for old PTEs, adds cold pages to swapcache and unmaps them. To avoid confusion, the term "iteration" specifically means the traversal of an entire mm_struct list; the term "walk" will be applied to page tables and the rmap, as usual. An mm_struct list is maintained for each memcg, and an mm_struct follows its owner task to the new memcg when this task is migrated. Given an lruvec, the aging iterates lruvec_memcg()->mm_list and calls walk_page_range() with each mm_struct on this list to promote hot pages before it increments max_seq. When multiple page table walkers iterate the same list, each of them gets a unique mm_struct; therefore they can run concurrently. Page table walkers ignore any misplaced pages, e.g., if an mm_struct was migrated, pages it left in the previous memcg will not be promoted when its current memcg is under reclaim. Similarly, page table walkers will not promote pages from nodes other than the one under reclaim. This patch uses the following optimizations when walking page tables: 1. It tracks the usage of mm_struct's between context switches so that page table walkers can skip processes that have been sleeping since the last iteration. 2. It uses generational Bloom filters to record populated branches so that page table walkers can reduce their search space based on the query results, e.g., to skip page tables containing mostly holes or misplaced pages. 3. It takes advantage of the accessed bit in non-leaf PMD entries when CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG=y. 4. It does not zigzag between a PGD table and the same PMD table spanning multiple VMAs. IOW, it finishes all the VMAs within the range of the same PMD table before it returns to a PGD table. This improves the cache performance for workloads that have large numbers of tiny VMAs [2], especially when CONFIG_PGTABLE_LEVELS=5. Server benchmark results: Single workload: fio (buffered I/O): no change Single workload: memcached (anon): +[8, 10]% Ops/sec KB/sec patch1-7: 1147696.57 44640.29 patch1-8: 1245274.91 48435.66 Configurations: no change Client benchmark results: kswapd profiles: patch1-7 48.16% lzo1x_1_do_compress (real work) 8.20% page_vma_mapped_walk (overhead) 7.06% _raw_spin_unlock_irq 2.92% ptep_clear_flush 2.53% __zram_bvec_write 2.11% do_raw_spin_lock 2.02% memmove 1.93% lru_gen_look_around 1.56% free_unref_page_list 1.40% memset patch1-8 49.44% lzo1x_1_do_compress (real work) 6.19% page_vma_mapped_walk (overhead) 5.97% _raw_spin_unlock_irq 3.13% get_pfn_folio 2.85% ptep_clear_flush 2.42% __zram_bvec_write 2.08% do_raw_spin_lock 1.92% memmove 1.44% alloc_zspage 1.36% memset Configurations: no change Thanks to the following developers for their efforts [3]. kernel test robot <lkp@intel.com> [1] https://lwn.net/Articles/23732/ [2] https://llvm.org/docs/ScudoHardenedAllocator.html [3] https://lore.kernel.org/r/202204160827.ekEARWQo-lkp@intel.com/ Link: https://lkml.kernel.org/r/20220918080010.2920238-9-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Barry Song <baohua@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
018ee47f |
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18-Sep-2022 |
Yu Zhao <yuzhao@google.com> |
mm: multi-gen LRU: exploit locality in rmap Searching the rmap for PTEs mapping each page on an LRU list (to test and clear the accessed bit) can be expensive because pages from different VMAs (PA space) are not cache friendly to the rmap (VA space). For workloads mostly using mapped pages, searching the rmap can incur the highest CPU cost in the reclaim path. This patch exploits spatial locality to reduce the trips into the rmap. When shrink_page_list() walks the rmap and finds a young PTE, a new function lru_gen_look_around() scans at most BITS_PER_LONG-1 adjacent PTEs. On finding another young PTE, it clears the accessed bit and updates the gen counter of the page mapped by this PTE to (max_seq%MAX_NR_GENS)+1. Server benchmark results: Single workload: fio (buffered I/O): no change Single workload: memcached (anon): +[3, 5]% Ops/sec KB/sec patch1-6: 1106168.46 43025.04 patch1-7: 1147696.57 44640.29 Configurations: no change Client benchmark results: kswapd profiles: patch1-6 39.03% lzo1x_1_do_compress (real work) 18.47% page_vma_mapped_walk (overhead) 6.74% _raw_spin_unlock_irq 3.97% do_raw_spin_lock 2.49% ptep_clear_flush 2.48% anon_vma_interval_tree_iter_first 1.92% folio_referenced_one 1.88% __zram_bvec_write 1.48% memmove 1.31% vma_interval_tree_iter_next patch1-7 48.16% lzo1x_1_do_compress (real work) 8.20% page_vma_mapped_walk (overhead) 7.06% _raw_spin_unlock_irq 2.92% ptep_clear_flush 2.53% __zram_bvec_write 2.11% do_raw_spin_lock 2.02% memmove 1.93% lru_gen_look_around 1.56% free_unref_page_list 1.40% memset Configurations: no change Link: https://lkml.kernel.org/r/20220918080010.2920238-8-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Barry Song <baohua@kernel.org> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
ac35a490 |
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18-Sep-2022 |
Yu Zhao <yuzhao@google.com> |
mm: multi-gen LRU: minimal implementation To avoid confusion, the terms "promotion" and "demotion" will be applied to the multi-gen LRU, as a new convention; the terms "activation" and "deactivation" will be applied to the active/inactive LRU, as usual. The aging produces young generations. Given an lruvec, it increments max_seq when max_seq-min_seq+1 approaches MIN_NR_GENS. The aging promotes hot pages to the youngest generation when it finds them accessed through page tables; the demotion of cold pages happens consequently when it increments max_seq. Promotion in the aging path does not involve any LRU list operations, only the updates of the gen counter and lrugen->nr_pages[]; demotion, unless as the result of the increment of max_seq, requires LRU list operations, e.g., lru_deactivate_fn(). The aging has the complexity O(nr_hot_pages), since it is only interested in hot pages. The eviction consumes old generations. Given an lruvec, it increments min_seq when lrugen->lists[] indexed by min_seq%MAX_NR_GENS becomes empty. A feedback loop modeled after the PID controller monitors refaults over anon and file types and decides which type to evict when both types are available from the same generation. The protection of pages accessed multiple times through file descriptors takes place in the eviction path. Each generation is divided into multiple tiers. A page accessed N times through file descriptors is in tier order_base_2(N). Tiers do not have dedicated lrugen->lists[], only bits in folio->flags. The aforementioned feedback loop also monitors refaults over all tiers and decides when to protect pages in which tiers (N>1), using the first tier (N=0,1) as a baseline. The first tier contains single-use unmapped clean pages, which are most likely the best choices. In contrast to promotion in the aging path, the protection of a page in the eviction path is achieved by moving this page to the next generation, i.e., min_seq+1, if the feedback loop decides so. This approach has the following advantages: 1. It removes the cost of activation in the buffered access path by inferring whether pages accessed multiple times through file descriptors are statistically hot and thus worth protecting in the eviction path. 2. It takes pages accessed through page tables into account and avoids overprotecting pages accessed multiple times through file descriptors. (Pages accessed through page tables are in the first tier, since N=0.) 3. More tiers provide better protection for pages accessed more than twice through file descriptors, when under heavy buffered I/O workloads. Server benchmark results: Single workload: fio (buffered I/O): +[30, 32]% IOPS BW 5.19-rc1: 2673k 10.2GiB/s patch1-6: 3491k 13.3GiB/s Single workload: memcached (anon): -[4, 6]% Ops/sec KB/sec 5.19-rc1: 1161501.04 45177.25 patch1-6: 1106168.46 43025.04 Configurations: CPU: two Xeon 6154 Mem: total 256G Node 1 was only used as a ram disk to reduce the variance in the results. patch drivers/block/brd.c <<EOF 99,100c99,100 < gfp_flags = GFP_NOIO | __GFP_ZERO | __GFP_HIGHMEM; < page = alloc_page(gfp_flags); --- > gfp_flags = GFP_NOIO | __GFP_ZERO | __GFP_HIGHMEM | __GFP_THISNODE; > page = alloc_pages_node(1, gfp_flags, 0); EOF cat >>/etc/systemd/system.conf <<EOF CPUAffinity=numa NUMAPolicy=bind NUMAMask=0 EOF cat >>/etc/memcached.conf <<EOF -m 184320 -s /var/run/memcached/memcached.sock -a 0766 -t 36 -B binary EOF cat fio.sh modprobe brd rd_nr=1 rd_size=113246208 swapoff -a mkfs.ext4 /dev/ram0 mount -t ext4 /dev/ram0 /mnt mkdir /sys/fs/cgroup/user.slice/test echo 38654705664 >/sys/fs/cgroup/user.slice/test/memory.max echo $$ >/sys/fs/cgroup/user.slice/test/cgroup.procs fio -name=mglru --numjobs=72 --directory=/mnt --size=1408m \ --buffered=1 --ioengine=io_uring --iodepth=128 \ --iodepth_batch_submit=32 --iodepth_batch_complete=32 \ --rw=randread --random_distribution=random --norandommap \ --time_based --ramp_time=10m --runtime=5m --group_reporting cat memcached.sh modprobe brd rd_nr=1 rd_size=113246208 swapoff -a mkswap /dev/ram0 swapon /dev/ram0 memtier_benchmark -S /var/run/memcached/memcached.sock \ -P memcache_binary -n allkeys --key-minimum=1 \ --key-maximum=65000000 --key-pattern=P:P -c 1 -t 36 \ --ratio 1:0 --pipeline 8 -d 2000 memtier_benchmark -S /var/run/memcached/memcached.sock \ -P memcache_binary -n allkeys --key-minimum=1 \ --key-maximum=65000000 --key-pattern=R:R -c 1 -t 36 \ --ratio 0:1 --pipeline 8 --randomize --distinct-client-seed Client benchmark results: kswapd profiles: 5.19-rc1 40.33% page_vma_mapped_walk (overhead) 21.80% lzo1x_1_do_compress (real work) 7.53% do_raw_spin_lock 3.95% _raw_spin_unlock_irq 2.52% vma_interval_tree_iter_next 2.37% folio_referenced_one 2.28% vma_interval_tree_subtree_search 1.97% anon_vma_interval_tree_iter_first 1.60% ptep_clear_flush 1.06% __zram_bvec_write patch1-6 39.03% lzo1x_1_do_compress (real work) 18.47% page_vma_mapped_walk (overhead) 6.74% _raw_spin_unlock_irq 3.97% do_raw_spin_lock 2.49% ptep_clear_flush 2.48% anon_vma_interval_tree_iter_first 1.92% folio_referenced_one 1.88% __zram_bvec_write 1.48% memmove 1.31% vma_interval_tree_iter_next Configurations: CPU: single Snapdragon 7c Mem: total 4G ChromeOS MemoryPressure [1] [1] https://chromium.googlesource.com/chromiumos/platform/tast-tests/ Link: https://lkml.kernel.org/r/20220918080010.2920238-7-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Barry Song <baohua@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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ec1c86b2 |
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18-Sep-2022 |
Yu Zhao <yuzhao@google.com> |
mm: multi-gen LRU: groundwork Evictable pages are divided into multiple generations for each lruvec. The youngest generation number is stored in lrugen->max_seq for both anon and file types as they are aged on an equal footing. The oldest generation numbers are stored in lrugen->min_seq[] separately for anon and file types as clean file pages can be evicted regardless of swap constraints. These three variables are monotonically increasing. Generation numbers are truncated into order_base_2(MAX_NR_GENS+1) bits in order to fit into the gen counter in folio->flags. Each truncated generation number is an index to lrugen->lists[]. The sliding window technique is used to track at least MIN_NR_GENS and at most MAX_NR_GENS generations. The gen counter stores a value within [1, MAX_NR_GENS] while a page is on one of lrugen->lists[]. Otherwise it stores 0. There are two conceptually independent procedures: "the aging", which produces young generations, and "the eviction", which consumes old generations. They form a closed-loop system, i.e., "the page reclaim". Both procedures can be invoked from userspace for the purposes of working set estimation and proactive reclaim. These techniques are commonly used to optimize job scheduling (bin packing) in data centers [1][2]. To avoid confusion, the terms "hot" and "cold" will be applied to the multi-gen LRU, as a new convention; the terms "active" and "inactive" will be applied to the active/inactive LRU, as usual. The protection of hot pages and the selection of cold pages are based on page access channels and patterns. There are two access channels: one through page tables and the other through file descriptors. The protection of the former channel is by design stronger because: 1. The uncertainty in determining the access patterns of the former channel is higher due to the approximation of the accessed bit. 2. The cost of evicting the former channel is higher due to the TLB flushes required and the likelihood of encountering the dirty bit. 3. The penalty of underprotecting the former channel is higher because applications usually do not prepare themselves for major page faults like they do for blocked I/O. E.g., GUI applications commonly use dedicated I/O threads to avoid blocking rendering threads. There are also two access patterns: one with temporal locality and the other without. For the reasons listed above, the former channel is assumed to follow the former pattern unless VM_SEQ_READ or VM_RAND_READ is present; the latter channel is assumed to follow the latter pattern unless outlying refaults have been observed [3][4]. The next patch will address the "outlying refaults". Three macros, i.e., LRU_REFS_WIDTH, LRU_REFS_PGOFF and LRU_REFS_MASK, used later are added in this patch to make the entire patchset less diffy. A page is added to the youngest generation on faulting. The aging needs to check the accessed bit at least twice before handing this page over to the eviction. The first check takes care of the accessed bit set on the initial fault; the second check makes sure this page has not been used since then. This protocol, AKA second chance, requires a minimum of two generations, hence MIN_NR_GENS. [1] https://dl.acm.org/doi/10.1145/3297858.3304053 [2] https://dl.acm.org/doi/10.1145/3503222.3507731 [3] https://lwn.net/Articles/495543/ [4] https://lwn.net/Articles/815342/ Link: https://lkml.kernel.org/r/20220918080010.2920238-6-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Barry Song <baohua@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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b4a0215e |
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27-Aug-2022 |
Kefeng Wang <wangkefeng.wang@huawei.com> |
mm: fix null-ptr-deref in kswapd_is_running() kswapd_run/stop() will set pgdat->kswapd to NULL, which could race with kswapd_is_running() in kcompactd(), kswapd_run/stop() kcompactd() kswapd_is_running() pgdat->kswapd // error or nomal ptr verify pgdat->kswapd // load non-NULL pgdat->kswapd pgdat->kswapd = NULL task_is_running(pgdat->kswapd) // Null pointer derefence KASAN reports the null-ptr-deref shown below, vmscan: Failed to start kswapd on node 0 ... BUG: KASAN: null-ptr-deref in kcompactd+0x440/0x504 Read of size 8 at addr 0000000000000024 by task kcompactd0/37 CPU: 0 PID: 37 Comm: kcompactd0 Kdump: loaded Tainted: G OE 5.10.60 #1 Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 Call trace: dump_backtrace+0x0/0x394 show_stack+0x34/0x4c dump_stack+0x158/0x1e4 __kasan_report+0x138/0x140 kasan_report+0x44/0xdc __asan_load8+0x94/0xd0 kcompactd+0x440/0x504 kthread+0x1a4/0x1f0 ret_from_fork+0x10/0x18 At present kswapd/kcompactd_run() and kswapd/kcompactd_stop() are protected by mem_hotplug_begin/done(), but without kcompactd(). There is no need to involve memory hotplug lock in kcompactd(), so let's add a new mutex to protect pgdat->kswapd accesses. Also, because the kcompactd task will check the state of kswapd task, it's better to call kcompactd_stop() before kswapd_stop() to reduce lock conflicts. [akpm@linux-foundation.org: add comments] Link: https://lkml.kernel.org/r/20220827111959.186838-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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0192445c |
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15-Aug-2022 |
Zi Yan <ziy@nvidia.com> |
arch: mm: rename FORCE_MAX_ZONEORDER to ARCH_FORCE_MAX_ORDER This Kconfig option is used by individual arch to set its desired MAX_ORDER. Rename it to reflect its actual use. Link: https://lkml.kernel.org/r/20220815143959.1511278-1-zi.yan@sent.com Acked-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Zi Yan <ziy@nvidia.com> Acked-by: Guo Ren <guoren@kernel.org> [csky] Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64] Acked-by: Huacai Chen <chenhuacai@kernel.org> [LoongArch] Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Taichi Sugaya <sugaya.taichi@socionext.com> Cc: Neil Armstrong <narmstrong@baylibre.com> Cc: Qin Jian <qinjian@cqplus1.com> Cc: Guo Ren <guoren@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Zankel <chris@zankel.net> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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c959924b |
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13-Jul-2022 |
Huang Ying <ying.huang@intel.com> |
memory tiering: adjust hot threshold automatically The promotion hot threshold is workload and system configuration dependent. So in this patch, a method to adjust the hot threshold automatically is implemented. The basic idea is to control the number of the candidate promotion pages to match the promotion rate limit. If the hint page fault latency of a page is less than the hot threshold, we will try to promote the page, and the page is called the candidate promotion page. If the number of the candidate promotion pages in the statistics interval is much more than the promotion rate limit, the hot threshold will be decreased to reduce the number of the candidate promotion pages. Otherwise, the hot threshold will be increased to increase the number of the candidate promotion pages. To make the above method works, in each statistics interval, the total number of the pages to check (on which the hint page faults occur) and the hot/cold distribution need to be stable. Because the page tables are scanned linearly in NUMA balancing, but the hot/cold distribution isn't uniform along the address usually, the statistics interval should be larger than the NUMA balancing scan period. So in the patch, the max scan period is used as statistics interval and it works well in our tests. Link: https://lkml.kernel.org/r/20220713083954.34196-4-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: osalvador <osalvador@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Wei Xu <weixugc@google.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Zhong Jiang <zhongjiang-ali@linux.alibaba.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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c6833e10 |
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13-Jul-2022 |
Huang Ying <ying.huang@intel.com> |
memory tiering: rate limit NUMA migration throughput In NUMA balancing memory tiering mode, if there are hot pages in slow memory node and cold pages in fast memory node, we need to promote/demote hot/cold pages between the fast and cold memory nodes. A choice is to promote/demote as fast as possible. But the CPU cycles and memory bandwidth consumed by the high promoting/demoting throughput will hurt the latency of some workload because of accessing inflating and slow memory bandwidth contention. A way to resolve this issue is to restrict the max promoting/demoting throughput. It will take longer to finish the promoting/demoting. But the workload latency will be better. This is implemented in this patch as the page promotion rate limit mechanism. The number of the candidate pages to be promoted to the fast memory node via NUMA balancing is counted, if the count exceeds the limit specified by the users, the NUMA balancing promotion will be stopped until the next second. A new sysctl knob kernel.numa_balancing_promote_rate_limit_MBps is added for the users to specify the limit. Link: https://lkml.kernel.org/r/20220713083954.34196-3-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: osalvador <osalvador@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Wei Xu <weixugc@google.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Zhong Jiang <zhongjiang-ali@linux.alibaba.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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e9c2dbc8 |
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07-Aug-2022 |
Yang Yang <yang.yang29@zte.com.cn> |
mm/vmscan: define macros for refaults in struct lruvec The magic number 0 and 1 are used in several places in vmscan.c. Define macros for them to improve code readability. Link: https://lkml.kernel.org/r/20220808005644.1721066-1-yang.yang29@zte.com.cn Signed-off-by: Yang Yang <yang.yang29@zte.com.cn> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
ebc97a52 |
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22-Aug-2022 |
Yosry Ahmed <yosryahmed@google.com> |
mm: add NR_SECONDARY_PAGETABLE to count secondary page table uses. We keep track of several kernel memory stats (total kernel memory, page tables, stack, vmalloc, etc) on multiple levels (global, per-node, per-memcg, etc). These stats give insights to users to how much memory is used by the kernel and for what purposes. Currently, memory used by KVM mmu is not accounted in any of those kernel memory stats. This patch series accounts the memory pages used by KVM for page tables in those stats in a new NR_SECONDARY_PAGETABLE stat. This stat can be later extended to account for other types of secondary pages tables (e.g. iommu page tables). KVM has a decent number of large allocations that aren't for page tables, but for most of them, the number/size of those allocations scales linearly with either the number of vCPUs or the amount of memory assigned to the VM. KVM's secondary page table allocations do not scale linearly, especially when nested virtualization is in use. From a KVM perspective, NR_SECONDARY_PAGETABLE will scale with KVM's per-VM pages_{4k,2m,1g} stats unless the guest is doing something bizarre (e.g. accessing only 4kb chunks of 2mb pages so that KVM is forced to allocate a large number of page tables even though the guest isn't accessing that much memory). However, someone would need to either understand how KVM works to make that connection, or know (or be told) to go look at KVM's stats if they're running VMs to better decipher the stats. Furthermore, having NR_PAGETABLE side-by-side with NR_SECONDARY_PAGETABLE is informative. For example, when backing a VM with THP vs. HugeTLB, NR_SECONDARY_PAGETABLE is roughly the same, but NR_PAGETABLE is an order of magnitude higher with THP. So having this stat will at the very least prove to be useful for understanding tradeoffs between VM backing types, and likely even steer folks towards potential optimizations. The original discussion with more details about the rationale: https://lore.kernel.org/all/87ilqoi77b.wl-maz@kernel.org This stat will be used by subsequent patches to count KVM mmu memory usage. Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Acked-by: Shakeel Butt <shakeelb@google.com> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220823004639.2387269-2-yosryahmed@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
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bb077c3f |
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26-Jul-2022 |
Kefeng Wang <wangkefeng.wang@huawei.com> |
mm: cleanup is_highmem() It is unnecessary to add CONFIG_HIGHMEM check in is_highmem(), which has been done in is_highmem_idx(), and move is_highmem() close to is_highmem_idx(). This has no functional impact. Link: https://lkml.kernel.org/r/20220726131816.149075-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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4b23a68f |
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24-Jun-2022 |
Mel Gorman <mgorman@techsingularity.net> |
mm/page_alloc: protect PCP lists with a spinlock Currently the PCP lists are protected by using local_lock_irqsave to prevent migration and IRQ reentrancy but this is inconvenient. Remote draining of the lists is impossible and a workqueue is required and every task allocation/free must disable then enable interrupts which is expensive. As preparation for dealing with both of those problems, protect the lists with a spinlock. The IRQ-unsafe version of the lock is used because IRQs are already disabled by local_lock_irqsave. spin_trylock is used in combination with local_lock_irqsave() but later will be replaced with a spin_trylock_irqsave when the local_lock is removed. The per_cpu_pages still fits within the same number of cache lines after this patch relative to before the series. struct per_cpu_pages { spinlock_t lock; /* 0 4 */ int count; /* 4 4 */ int high; /* 8 4 */ int batch; /* 12 4 */ short int free_factor; /* 16 2 */ short int expire; /* 18 2 */ /* XXX 4 bytes hole, try to pack */ struct list_head lists[13]; /* 24 208 */ /* size: 256, cachelines: 4, members: 7 */ /* sum members: 228, holes: 1, sum holes: 4 */ /* padding: 24 */ } __attribute__((__aligned__(64))); There is overhead in the fast path due to acquiring the spinlock even though the spinlock is per-cpu and uncontended in the common case. Page Fault Test (PFT) running on a 1-socket reported the following results on a 1 socket machine. 5.19.0-rc3 5.19.0-rc3 vanilla mm-pcpspinirq-v5r16 Hmean faults/sec-1 869275.7381 ( 0.00%) 874597.5167 * 0.61%* Hmean faults/sec-3 2370266.6681 ( 0.00%) 2379802.0362 * 0.40%* Hmean faults/sec-5 2701099.7019 ( 0.00%) 2664889.7003 * -1.34%* Hmean faults/sec-7 3517170.9157 ( 0.00%) 3491122.8242 * -0.74%* Hmean faults/sec-8 3965729.6187 ( 0.00%) 3939727.0243 * -0.66%* There is a small hit in the number of faults per second but given that the results are more stable, it's borderline noise. [akpm@linux-foundation.org: add missing local_unlock_irqrestore() on contention path] Link: https://lkml.kernel.org/r/20220624125423.6126-6-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Tested-by: Yu Zhao <yuzhao@google.com> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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5d0a661d |
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24-Jun-2022 |
Mel Gorman <mgorman@techsingularity.net> |
mm/page_alloc: use only one PCP list for THP-sized allocations The per_cpu_pages is cache-aligned on a standard x86-64 distribution configuration but a later patch will add a new field which would push the structure into the next cache line. Use only one list to store THP-sized pages on the per-cpu list. This assumes that the vast majority of THP-sized allocations are GFP_MOVABLE but even if it was another type, it would not contribute to serious fragmentation that potentially causes a later THP allocation failure. Align per_cpu_pages on the cacheline boundary to ensure there is no false cache sharing. After this patch, the structure sizing is; struct per_cpu_pages { int count; /* 0 4 */ int high; /* 4 4 */ int batch; /* 8 4 */ short int free_factor; /* 12 2 */ short int expire; /* 14 2 */ struct list_head lists[13]; /* 16 208 */ /* size: 256, cachelines: 4, members: 6 */ /* padding: 32 */ } __attribute__((__aligned__(64))); Link: https://lkml.kernel.org/r/20220624125423.6126-3-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Tested-by: Minchan Kim <minchan@kernel.org> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Nicolas Saenz Julienne <nsaenzju@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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5bb88dc5 |
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15-Jul-2022 |
Alex Sierra <alex.sierra@amd.com> |
mm: move page zone helpers from mm.h to mmzone.h It makes more sense to have these helpers in zone specific header file, rather than the generic mm.h Link: https://lkml.kernel.org/r/20220715150521.18165-3-alex.sierra@amd.com Signed-off-by: Alex Sierra <alex.sierra@amd.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Christoph Hellwig <hch@lst.de> Cc: David Hildenbrand <david@redhat.com> Cc: Felix Kuehling <Felix.Kuehling@amd.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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e8da368a |
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20-Jun-2022 |
Yun-Ze Li <p76091292@gs.ncku.edu.tw> |
mm, docs: fix comments that mention mem_hotplug_end() Comments that mention mem_hotplug_end() are confusing as there is no function called mem_hotplug_end(). Fix them by replacing all the occurences of mem_hotplug_end() in the comments with mem_hotplug_done(). [akpm@linux-foundation.org: grammatical fixes] Link: https://lkml.kernel.org/r/20220620071516.1286101-1-p76091292@gs.ncku.edu.tw Signed-off-by: Yun-Ze Li <p76091292@gs.ncku.edu.tw> Cc: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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ed7802dd |
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17-Jun-2022 |
Muchun Song <songmuchun@bytedance.com> |
mm: memory_hotplug: enumerate all supported section flags Patch series "make hugetlb_optimize_vmemmap compatible with memmap_on_memory", v3. This series makes hugetlb_optimize_vmemmap compatible with memmap_on_memory. This patch (of 2): We are almost running out of section flags, only one bit is available in the worst case (powerpc with 256k pages). However, there are still some free bits (in ->section_mem_map) on other architectures (e.g. x86_64 has 10 bits available, arm64 has 8 bits available with worst case of 64K pages). We have hard coded those numbers in code, it is inconvenient to use those bits on other architectures except powerpc. So transfer those section flags to enumeration to make it easy to add new section flags in the future. Also, move SECTION_TAINT_ZONE_DEVICE into the scope of CONFIG_ZONE_DEVICE to save a bit on non-zone-device case. [songmuchun@bytedance.com: replace enum with defines per David] Link: https://lkml.kernel.org/r/20220620110616.12056-2-songmuchun@bytedance.com Link: https://lkml.kernel.org/r/20220617135650.74901-1-songmuchun@bytedance.com Link: https://lkml.kernel.org/r/20220617135650.74901-2-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Xiongchun Duan <duanxiongchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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11ac3e87 |
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12-May-2022 |
Zi Yan <ziy@nvidia.com> |
mm: cma: use pageblock_order as the single alignment Now alloc_contig_range() works at pageblock granularity. Change CMA allocation, which uses alloc_contig_range(), to use pageblock_nr_pages alignment. Link: https://lkml.kernel.org/r/20220425143118.2850746-6-zi.yan@sent.com Signed-off-by: Zi Yan <ziy@nvidia.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: David Hildenbrand <david@redhat.com> Cc: Eric Ren <renzhengeek@gmail.com> Cc: kernel test robot <lkp@intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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a431dbbc |
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08-Apr-2022 |
Waiman Long <longman@redhat.com> |
mm/sparsemem: fix 'mem_section' will never be NULL gcc 12 warning The gcc 12 compiler reports a "'mem_section' will never be NULL" warning on the following code: static inline struct mem_section *__nr_to_section(unsigned long nr) { #ifdef CONFIG_SPARSEMEM_EXTREME if (!mem_section) return NULL; #endif if (!mem_section[SECTION_NR_TO_ROOT(nr)]) return NULL; : It happens with CONFIG_SPARSEMEM_EXTREME off. The mem_section definition is #ifdef CONFIG_SPARSEMEM_EXTREME extern struct mem_section **mem_section; #else extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]; #endif In the !CONFIG_SPARSEMEM_EXTREME case, mem_section is a static 2-dimensional array and so the check "!mem_section[SECTION_NR_TO_ROOT(nr)]" doesn't make sense. Fix this warning by moving the "!mem_section[SECTION_NR_TO_ROOT(nr)]" check up inside the CONFIG_SPARSEMEM_EXTREME block and adding an explicit NR_SECTION_ROOTS check to make sure that there is no out-of-bound array access. Link: https://lkml.kernel.org/r/20220331180246.2746210-1-longman@redhat.com Fixes: 3e347261a80b ("sparsemem extreme implementation") Signed-off-by: Waiman Long <longman@redhat.com> Reported-by: Justin Forbes <jforbes@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Rafael Aquini <aquini@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c574bbe9 |
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22-Mar-2022 |
Huang Ying <ying.huang@intel.com> |
NUMA balancing: optimize page placement for memory tiering system With the advent of various new memory types, some machines will have multiple types of memory, e.g. DRAM and PMEM (persistent memory). The memory subsystem of these machines can be called memory tiering system, because the performance of the different types of memory are usually different. In such system, because of the memory accessing pattern changing etc, some pages in the slow memory may become hot globally. So in this patch, the NUMA balancing mechanism is enhanced to optimize the page placement among the different memory types according to hot/cold dynamically. In a typical memory tiering system, there are CPUs, fast memory and slow memory in each physical NUMA node. The CPUs and the fast memory will be put in one logical node (called fast memory node), while the slow memory will be put in another (faked) logical node (called slow memory node). That is, the fast memory is regarded as local while the slow memory is regarded as remote. So it's possible for the recently accessed pages in the slow memory node to be promoted to the fast memory node via the existing NUMA balancing mechanism. The original NUMA balancing mechanism will stop to migrate pages if the free memory of the target node becomes below the high watermark. This is a reasonable policy if there's only one memory type. But this makes the original NUMA balancing mechanism almost do not work to optimize page placement among different memory types. Details are as follows. It's the common cases that the working-set size of the workload is larger than the size of the fast memory nodes. Otherwise, it's unnecessary to use the slow memory at all. So, there are almost always no enough free pages in the fast memory nodes, so that the globally hot pages in the slow memory node cannot be promoted to the fast memory node. To solve the issue, we have 2 choices as follows, a. Ignore the free pages watermark checking when promoting hot pages from the slow memory node to the fast memory node. This will create some memory pressure in the fast memory node, thus trigger the memory reclaiming. So that, the cold pages in the fast memory node will be demoted to the slow memory node. b. Define a new watermark called wmark_promo which is higher than wmark_high, and have kswapd reclaiming pages until free pages reach such watermark. The scenario is as follows: when we want to promote hot-pages from a slow memory to a fast memory, but fast memory's free pages would go lower than high watermark with such promotion, we wake up kswapd with wmark_promo watermark in order to demote cold pages and free us up some space. So, next time we want to promote hot-pages we might have a chance of doing so. The choice "a" may create high memory pressure in the fast memory node. If the memory pressure of the workload is high, the memory pressure may become so high that the memory allocation latency of the workload is influenced, e.g. the direct reclaiming may be triggered. The choice "b" works much better at this aspect. If the memory pressure of the workload is high, the hot pages promotion will stop earlier because its allocation watermark is higher than that of the normal memory allocation. So in this patch, choice "b" is implemented. A new zone watermark (WMARK_PROMO) is added. Which is larger than the high watermark and can be controlled via watermark_scale_factor. In addition to the original page placement optimization among sockets, the NUMA balancing mechanism is extended to be used to optimize page placement according to hot/cold among different memory types. So the sysctl user space interface (numa_balancing) is extended in a backward compatible way as follow, so that the users can enable/disable these functionality individually. The sysctl is converted from a Boolean value to a bits field. The definition of the flags is, - 0: NUMA_BALANCING_DISABLED - 1: NUMA_BALANCING_NORMAL - 2: NUMA_BALANCING_MEMORY_TIERING We have tested the patch with the pmbench memory accessing benchmark with the 80:20 read/write ratio and the Gauss access address distribution on a 2 socket Intel server with Optane DC Persistent Memory Model. The test results shows that the pmbench score can improve up to 95.9%. Thanks Andrew Morton to help fix the document format error. Link: https://lkml.kernel.org/r/20220221084529.1052339-3-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Yang Shi <shy828301@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Rik van Riel <riel@surriel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Wei Xu <weixugc@google.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: zhongjiang-ali <zhongjiang-ali@linux.alibaba.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Feng Tang <feng.tang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e39bb6be |
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22-Mar-2022 |
Huang Ying <ying.huang@intel.com> |
NUMA Balancing: add page promotion counter Patch series "NUMA balancing: optimize memory placement for memory tiering system", v13 With the advent of various new memory types, some machines will have multiple types of memory, e.g. DRAM and PMEM (persistent memory). The memory subsystem of these machines can be called memory tiering system, because the performance of the different types of memory are different. After commit c221c0b0308f ("device-dax: "Hotplug" persistent memory for use like normal RAM"), the PMEM could be used as the cost-effective volatile memory in separate NUMA nodes. In a typical memory tiering system, there are CPUs, DRAM and PMEM in each physical NUMA node. The CPUs and the DRAM will be put in one logical node, while the PMEM will be put in another (faked) logical node. To optimize the system overall performance, the hot pages should be placed in DRAM node. To do that, we need to identify the hot pages in the PMEM node and migrate them to DRAM node via NUMA migration. In the original NUMA balancing, there are already a set of existing mechanisms to identify the pages recently accessed by the CPUs in a node and migrate the pages to the node. So we can reuse these mechanisms to build the mechanisms to optimize the page placement in the memory tiering system. This is implemented in this patchset. At the other hand, the cold pages should be placed in PMEM node. So, we also need to identify the cold pages in the DRAM node and migrate them to PMEM node. In commit 26aa2d199d6f ("mm/migrate: demote pages during reclaim"), a mechanism to demote the cold DRAM pages to PMEM node under memory pressure is implemented. Based on that, the cold DRAM pages can be demoted to PMEM node proactively to free some memory space on DRAM node to accommodate the promoted hot PMEM pages. This is implemented in this patchset too. We have tested the solution with the pmbench memory accessing benchmark with the 80:20 read/write ratio and the Gauss access address distribution on a 2 socket Intel server with Optane DC Persistent Memory Model. The test results shows that the pmbench score can improve up to 95.9%. This patch (of 3): In a system with multiple memory types, e.g. DRAM and PMEM, the CPU and DRAM in one socket will be put in one NUMA node as before, while the PMEM will be put in another NUMA node as described in the description of the commit c221c0b0308f ("device-dax: "Hotplug" persistent memory for use like normal RAM"). So, the NUMA balancing mechanism will identify all PMEM accesses as remote access and try to promote the PMEM pages to DRAM. To distinguish the number of the inter-type promoted pages from that of the inter-socket migrated pages. A new vmstat count is added. The counter is per-node (count in the target node). So this can be used to identify promotion imbalance among the NUMA nodes. Link: https://lkml.kernel.org/r/20220301085329.3210428-1-ying.huang@intel.com Link: https://lkml.kernel.org/r/20220221084529.1052339-1-ying.huang@intel.com Link: https://lkml.kernel.org/r/20220221084529.1052339-2-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Rik van Riel <riel@surriel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Wei Xu <weixugc@google.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: zhongjiang-ali <zhongjiang-ali@linux.alibaba.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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7f37e49c |
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22-Mar-2022 |
Miaohe Lin <linmiaohe@huawei.com> |
mm/mmzone.h: remove unused macros Remove pgdat_page_nr, nid_page_nr and NODE_MEM_MAP. They are unused now. Link: https://lkml.kernel.org/r/20220127093210.62293-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1dd214b8 |
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22-Mar-2022 |
Zi Yan <ziy@nvidia.com> |
mm: page_alloc: avoid merging non-fallbackable pageblocks with others This is done in addition to MIGRATE_ISOLATE pageblock merge avoidance. It prepares for the upcoming removal of the MAX_ORDER-1 alignment requirement for CMA and alloc_contig_range(). MIGRATE_HIGHATOMIC should not merge with other migratetypes like MIGRATE_ISOLATE and MIGRARTE_CMA[1], so this commit prevents that too. Remove MIGRATE_CMA and MIGRATE_ISOLATE from fallbacks list, since they are never used. [1] https://lore.kernel.org/linux-mm/20211130100853.GP3366@techsingularity.net/ Link: https://lkml.kernel.org/r/20220124175957.1261961-1-zi.yan@sent.com Signed-off-by: Zi Yan <ziy@nvidia.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Mike Rapoport <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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62b31070 |
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14-Jan-2022 |
Baoquan He <bhe@redhat.com> |
mm_zone: add function to check if managed dma zone exists Patch series "Handle warning of allocation failure on DMA zone w/o managed pages", v4. **Problem observed: On x86_64, when crash is triggered and entering into kdump kernel, page allocation failure can always be seen. --------------------------------- DMA: preallocated 128 KiB GFP_KERNEL pool for atomic allocations swapper/0: page allocation failure: order:5, mode:0xcc1(GFP_KERNEL|GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0 CPU: 0 PID: 1 Comm: swapper/0 Call Trace: dump_stack+0x7f/0xa1 warn_alloc.cold+0x72/0xd6 ...... __alloc_pages+0x24d/0x2c0 ...... dma_atomic_pool_init+0xdb/0x176 do_one_initcall+0x67/0x320 ? rcu_read_lock_sched_held+0x3f/0x80 kernel_init_freeable+0x290/0x2dc ? rest_init+0x24f/0x24f kernel_init+0xa/0x111 ret_from_fork+0x22/0x30 Mem-Info: ------------------------------------ ***Root cause: In the current kernel, it assumes that DMA zone must have managed pages and try to request pages if CONFIG_ZONE_DMA is enabled. While this is not always true. E.g in kdump kernel of x86_64, only low 1M is presented and locked down at very early stage of boot, so that this low 1M won't be added into buddy allocator to become managed pages of DMA zone. This exception will always cause page allocation failure if page is requested from DMA zone. ***Investigation: This failure happens since below commit merged into linus's tree. 1a6a9044b967 x86/setup: Remove CONFIG_X86_RESERVE_LOW and reservelow= options 23721c8e92f7 x86/crash: Remove crash_reserve_low_1M() f1d4d47c5851 x86/setup: Always reserve the first 1M of RAM 7c321eb2b843 x86/kdump: Remove the backup region handling 6f599d84231f x86/kdump: Always reserve the low 1M when the crashkernel option is specified Before them, on x86_64, the low 640K area will be reused by kdump kernel. So in kdump kernel, the content of low 640K area is copied into a backup region for dumping before jumping into kdump. Then except of those firmware reserved region in [0, 640K], the left area will be added into buddy allocator to become available managed pages of DMA zone. However, after above commits applied, in kdump kernel of x86_64, the low 1M is reserved by memblock, but not released to buddy allocator. So any later page allocation requested from DMA zone will fail. At the beginning, if crashkernel is reserved, the low 1M need be locked down because AMD SME encrypts memory making the old backup region mechanims impossible when switching into kdump kernel. Later, it was also observed that there are BIOSes corrupting memory under 1M. To solve this, in commit f1d4d47c5851, the entire region of low 1M is always reserved after the real mode trampoline is allocated. Besides, recently, Intel engineer mentioned their TDX (Trusted domain extensions) which is under development in kernel also needs to lock down the low 1M. So we can't simply revert above commits to fix the page allocation failure from DMA zone as someone suggested. ***Solution: Currently, only DMA atomic pool and dma-kmalloc will initialize and request page allocation with GFP_DMA during bootup. So only initializ DMA atomic pool when DMA zone has available managed pages, otherwise just skip the initialization. For dma-kmalloc(), for the time being, let's mute the warning of allocation failure if requesting pages from DMA zone while no manged pages. Meanwhile, change code to use dma_alloc_xx/dma_map_xx API to replace kmalloc(GFP_DMA), or do not use GFP_DMA when calling kmalloc() if not necessary. Christoph is posting patches to fix those under drivers/scsi/. Finally, we can remove the need of dma-kmalloc() as people suggested. This patch (of 3): In some places of the current kernel, it assumes that dma zone must have managed pages if CONFIG_ZONE_DMA is enabled. While this is not always true. E.g in kdump kernel of x86_64, only low 1M is presented and locked down at very early stage of boot, so that there's no managed pages at all in DMA zone. This exception will always cause page allocation failure if page is requested from DMA zone. Here add function has_managed_dma() and the relevant helper functions to check if there's DMA zone with managed pages. It will be used in later patches. Link: https://lkml.kernel.org/r/20211223094435.248523-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20211223094435.248523-2-bhe@redhat.com Fixes: 6f599d84231f ("x86/kdump: Always reserve the low 1M when the crashkernel option is specified") Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: John Donnelly <john.p.donnelly@oracle.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Christoph Lameter <cl@linux.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Laight <David.Laight@ACULAB.COM> Cc: Borislav Petkov <bp@alien8.de> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1b4e3f26 |
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02-Dec-2021 |
Mel Gorman <mgorman@techsingularity.net> |
mm: vmscan: Reduce throttling due to a failure to make progress Mike Galbraith, Alexey Avramov and Darrick Wong all reported similar problems due to reclaim throttling for excessive lengths of time. In Alexey's case, a memory hog that should go OOM quickly stalls for several minutes before stalling. In Mike and Darrick's cases, a small memcg environment stalled excessively even though the system had enough memory overall. Commit 69392a403f49 ("mm/vmscan: throttle reclaim when no progress is being made") introduced the problem although commit a19594ca4a8b ("mm/vmscan: increase the timeout if page reclaim is not making progress") made it worse. Systems at or near an OOM state that cannot be recovered must reach OOM quickly and memcg should kill tasks if a memcg is near OOM. To address this, only stall for the first zone in the zonelist, reduce the timeout to 1 tick for VMSCAN_THROTTLE_NOPROGRESS and only stall if the scan control nr_reclaimed is 0, kswapd is still active and there were excessive pages pending for writeback. If kswapd has stopped reclaiming due to excessive failures, do not stall at all so that OOM triggers relatively quickly. Similarly, if an LRU is simply congested, only lightly throttle similar to NOPROGRESS. Alexey's original case was the most straight forward for i in {1..3}; do tail /dev/zero; done On vanilla 5.16-rc1, this test stalled heavily, after the patch the test completes in a few seconds similar to 5.15. Alexey's second test case added watching a youtube video while tail runs 10 times. On 5.15, playback only jitters slightly, 5.16-rc1 stalls a lot with lots of frames missing and numerous audio glitches. With this patch applies, the video plays similarly to 5.15. [lkp@intel.com: Fix W=1 build warning] Link: https://lore.kernel.org/r/99e779783d6c7fce96448a3402061b9dc1b3b602.camel@gmx.de Link: https://lore.kernel.org/r/20211124011954.7cab9bb4@mail.inbox.lv Link: https://lore.kernel.org/r/20211022144651.19914-1-mgorman@techsingularity.net Link: https://lore.kernel.org/r/20211202150614.22440-1-mgorman@techsingularity.net Link: https://linux-regtracking.leemhuis.info/regzbot/regression/20211124011954.7cab9bb4@mail.inbox.lv/ Reported-and-tested-by: Alexey Avramov <hakavlad@inbox.lv> Reported-and-tested-by: Mike Galbraith <efault@gmx.de> Reported-and-tested-by: Darrick J. Wong <djwong@kernel.org> Reported-by: kernel test robot <lkp@intel.com> Acked-by: Hugh Dickins <hughd@google.com> Tracked-by: Thorsten Leemhuis <regressions@leemhuis.info> Fixes: 69392a403f49 ("mm/vmscan: throttle reclaim when no progress is being made") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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69392a40 |
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05-Nov-2021 |
Mel Gorman <mgorman@techsingularity.net> |
mm/vmscan: throttle reclaim when no progress is being made Memcg reclaim throttles on congestion if no reclaim progress is made. This makes little sense, it might be due to writeback or a host of other factors. For !memcg reclaim, it's messy. Direct reclaim primarily is throttled in the page allocator if it is failing to make progress. Kswapd throttles if too many pages are under writeback and marked for immediate reclaim. This patch explicitly throttles if reclaim is failing to make progress. [vbabka@suse.cz: Remove redundant code] Link: https://lkml.kernel.org/r/20211022144651.19914-4-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: "Darrick J . Wong" <djwong@kernel.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: NeilBrown <neilb@suse.de> Cc: Rik van Riel <riel@surriel.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d818fca1 |
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05-Nov-2021 |
Mel Gorman <mgorman@techsingularity.net> |
mm/vmscan: throttle reclaim and compaction when too may pages are isolated Page reclaim throttles on congestion if too many parallel reclaim instances have isolated too many pages. This makes no sense, excessive parallelisation has nothing to do with writeback or congestion. This patch creates an additional workqueue to sleep on when too many pages are isolated. The throttled tasks are woken when the number of isolated pages is reduced or a timeout occurs. There may be some false positive wakeups for GFP_NOIO/GFP_NOFS callers but the tasks will throttle again if necessary. [shy828301@gmail.com: Wake up from compaction context] [vbabka@suse.cz: Account number of throttled tasks only for writeback] Link: https://lkml.kernel.org/r/20211022144651.19914-3-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: "Darrick J . Wong" <djwong@kernel.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: NeilBrown <neilb@suse.de> Cc: Rik van Riel <riel@surriel.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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8cd7c588 |
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05-Nov-2021 |
Mel Gorman <mgorman@techsingularity.net> |
mm/vmscan: throttle reclaim until some writeback completes if congested Patch series "Remove dependency on congestion_wait in mm/", v5. This series that removes all calls to congestion_wait in mm/ and deletes wait_iff_congested. It's not a clever implementation but congestion_wait has been broken for a long time [1]. Even if congestion throttling worked, it was never a great idea. While excessive dirty/writeback pages at the tail of the LRU is one possibility that reclaim may be slow, there is also the problem of too many pages being isolated and reclaim failing for other reasons (elevated references, too many pages isolated, excessive LRU contention etc). This series replaces the "congestion" throttling with 3 different types. - If there are too many dirty/writeback pages, sleep until a timeout or enough pages get cleaned - If too many pages are isolated, sleep until enough isolated pages are either reclaimed or put back on the LRU - If no progress is being made, direct reclaim tasks sleep until another task makes progress with acceptable efficiency. This was initially tested with a mix of workloads that used to trigger corner cases that no longer work. A new test case was created called "stutterp" (pagereclaim-stutterp-noreaders in mmtests) using a freshly created XFS filesystem. Note that it may be necessary to increase the timeout of ssh if executing remotely as ssh itself can get throttled and the connection may timeout. stutterp varies the number of "worker" processes from 4 up to NR_CPUS*4 to check the impact as the number of direct reclaimers increase. It has four types of worker. - One "anon latency" worker creates small mappings with mmap() and times how long it takes to fault the mapping reading it 4K at a time - X file writers which is fio randomly writing X files where the total size of the files add up to the allowed dirty_ratio. fio is allowed to run for a warmup period to allow some file-backed pages to accumulate. The duration of the warmup is based on the best-case linear write speed of the storage. - Y file readers which is fio randomly reading small files - Z anon memory hogs which continually map (100-dirty_ratio)% of memory - Total estimated WSS = (100+dirty_ration) percentage of memory X+Y+Z+1 == NR_WORKERS varying from 4 up to NR_CPUS*4 The intent is to maximise the total WSS with a mix of file and anon memory where some anonymous memory must be swapped and there is a high likelihood of dirty/writeback pages reaching the end of the LRU. The test can be configured to have no background readers to stress dirty/writeback pages. The results below are based on having zero readers. The short summary of the results is that the series works and stalls until some event occurs but the timeouts may need adjustment. The test results are not broken down by patch as the series should be treated as one block that replaces a broken throttling mechanism with a working one. Finally, three machines were tested but I'm reporting the worst set of results. The other two machines had much better latencies for example. First the results of the "anon latency" latency stutterp 5.15.0-rc1 5.15.0-rc1 vanilla mm-reclaimcongest-v5r4 Amean mmap-4 31.4003 ( 0.00%) 2661.0198 (-8374.52%) Amean mmap-7 38.1641 ( 0.00%) 149.2891 (-291.18%) Amean mmap-12 60.0981 ( 0.00%) 187.8105 (-212.51%) Amean mmap-21 161.2699 ( 0.00%) 213.9107 ( -32.64%) Amean mmap-30 174.5589 ( 0.00%) 377.7548 (-116.41%) Amean mmap-48 8106.8160 ( 0.00%) 1070.5616 ( 86.79%) Stddev mmap-4 41.3455 ( 0.00%) 27573.9676 (-66591.66%) Stddev mmap-7 53.5556 ( 0.00%) 4608.5860 (-8505.23%) Stddev mmap-12 171.3897 ( 0.00%) 5559.4542 (-3143.75%) Stddev mmap-21 1506.6752 ( 0.00%) 5746.2507 (-281.39%) Stddev mmap-30 557.5806 ( 0.00%) 7678.1624 (-1277.05%) Stddev mmap-48 61681.5718 ( 0.00%) 14507.2830 ( 76.48%) Max-90 mmap-4 31.4243 ( 0.00%) 83.1457 (-164.59%) Max-90 mmap-7 41.0410 ( 0.00%) 41.0720 ( -0.08%) Max-90 mmap-12 66.5255 ( 0.00%) 53.9073 ( 18.97%) Max-90 mmap-21 146.7479 ( 0.00%) 105.9540 ( 27.80%) Max-90 mmap-30 193.9513 ( 0.00%) 64.3067 ( 66.84%) Max-90 mmap-48 277.9137 ( 0.00%) 591.0594 (-112.68%) Max mmap-4 1913.8009 ( 0.00%) 299623.9695 (-15555.96%) Max mmap-7 2423.9665 ( 0.00%) 204453.1708 (-8334.65%) Max mmap-12 6845.6573 ( 0.00%) 221090.3366 (-3129.64%) Max mmap-21 56278.6508 ( 0.00%) 213877.3496 (-280.03%) Max mmap-30 19716.2990 ( 0.00%) 216287.6229 (-997.00%) Max mmap-48 477923.9400 ( 0.00%) 245414.8238 ( 48.65%) For most thread counts, the time to mmap() is unfortunately increased. In earlier versions of the series, this was lower but a large number of throttling events were reaching their timeout increasing the amount of inefficient scanning of the LRU. There is no prioritisation of reclaim tasks making progress based on each tasks rate of page allocation versus progress of reclaim. The variance is also impacted for high worker counts but in all cases, the differences in latency are not statistically significant due to very large maximum outliers. Max-90 shows that 90% of the stalls are comparable but the Max results show the massive outliers which are increased to to stalling. It is expected that this will be very machine dependant. Due to the test design, reclaim is difficult so allocations stall and there are variances depending on whether THPs can be allocated or not. The amount of memory will affect exactly how bad the corner cases are and how often they trigger. The warmup period calculation is not ideal as it's based on linear writes where as fio is randomly writing multiple files from multiple tasks so the start state of the test is variable. For example, these are the latencies on a single-socket machine that had more memory Amean mmap-4 42.2287 ( 0.00%) 49.6838 * -17.65%* Amean mmap-7 216.4326 ( 0.00%) 47.4451 * 78.08%* Amean mmap-12 2412.0588 ( 0.00%) 51.7497 ( 97.85%) Amean mmap-21 5546.2548 ( 0.00%) 51.8862 ( 99.06%) Amean mmap-30 1085.3121 ( 0.00%) 72.1004 ( 93.36%) The overall system CPU usage and elapsed time is as follows 5.15.0-rc3 5.15.0-rc3 vanilla mm-reclaimcongest-v5r4 Duration User 6989.03 983.42 Duration System 7308.12 799.68 Duration Elapsed 2277.67 2092.98 The patches reduce system CPU usage by 89% as the vanilla kernel is rarely stalling. The high-level /proc/vmstats show 5.15.0-rc1 5.15.0-rc1 vanilla mm-reclaimcongest-v5r2 Ops Direct pages scanned 1056608451.00 503594991.00 Ops Kswapd pages scanned 109795048.00 147289810.00 Ops Kswapd pages reclaimed 63269243.00 31036005.00 Ops Direct pages reclaimed 10803973.00 6328887.00 Ops Kswapd efficiency % 57.62 21.07 Ops Kswapd velocity 48204.98 57572.86 Ops Direct efficiency % 1.02 1.26 Ops Direct velocity 463898.83 196845.97 Kswapd scanned less pages but the detailed pattern is different. The vanilla kernel scans slowly over time where as the patches exhibits burst patterns of scan activity. Direct reclaim scanning is reduced by 52% due to stalling. The pattern for stealing pages is also slightly different. Both kernels exhibit spikes but the vanilla kernel when reclaiming shows pages being reclaimed over a period of time where as the patches tend to reclaim in spikes. The difference is that vanilla is not throttling and instead scanning constantly finding some pages over time where as the patched kernel throttles and reclaims in spikes. Ops Percentage direct scans 90.59 77.37 For direct reclaim, vanilla scanned 90.59% of pages where as with the patches, 77.37% were direct reclaim due to throttling Ops Page writes by reclaim 2613590.00 1687131.00 Page writes from reclaim context are reduced. Ops Page writes anon 2932752.00 1917048.00 And there is less swapping. Ops Page reclaim immediate 996248528.00 107664764.00 The number of pages encountered at the tail of the LRU tagged for immediate reclaim but still dirty/writeback is reduced by 89%. Ops Slabs scanned 164284.00 153608.00 Slab scan activity is similar. ftrace was used to gather stall activity Vanilla ------- 1 writeback_wait_iff_congested: usec_timeout=100000 usec_delayed=16000 2 writeback_wait_iff_congested: usec_timeout=100000 usec_delayed=12000 8 writeback_wait_iff_congested: usec_timeout=100000 usec_delayed=8000 29 writeback_wait_iff_congested: usec_timeout=100000 usec_delayed=4000 82394 writeback_wait_iff_congested: usec_timeout=100000 usec_delayed=0 The fast majority of wait_iff_congested calls do not stall at all. What is likely happening is that cond_resched() reschedules the task for a short period when the BDI is not registering congestion (which it never will in this test setup). 1 writeback_congestion_wait: usec_timeout=100000 usec_delayed=120000 2 writeback_congestion_wait: usec_timeout=100000 usec_delayed=132000 4 writeback_congestion_wait: usec_timeout=100000 usec_delayed=112000 380 writeback_congestion_wait: usec_timeout=100000 usec_delayed=108000 778 writeback_congestion_wait: usec_timeout=100000 usec_delayed=104000 congestion_wait if called always exceeds the timeout as there is no trigger to wake it up. Bottom line: Vanilla will throttle but it's not effective. Patch series ------------ Kswapd throttle activity was always due to scanning pages tagged for immediate reclaim at the tail of the LRU 1 usec_timeout=100000 usect_delayed=72000 reason=VMSCAN_THROTTLE_WRITEBACK 4 usec_timeout=100000 usect_delayed=20000 reason=VMSCAN_THROTTLE_WRITEBACK 5 usec_timeout=100000 usect_delayed=12000 reason=VMSCAN_THROTTLE_WRITEBACK 6 usec_timeout=100000 usect_delayed=16000 reason=VMSCAN_THROTTLE_WRITEBACK 11 usec_timeout=100000 usect_delayed=100000 reason=VMSCAN_THROTTLE_WRITEBACK 11 usec_timeout=100000 usect_delayed=8000 reason=VMSCAN_THROTTLE_WRITEBACK 94 usec_timeout=100000 usect_delayed=0 reason=VMSCAN_THROTTLE_WRITEBACK 112 usec_timeout=100000 usect_delayed=4000 reason=VMSCAN_THROTTLE_WRITEBACK The majority of events did not stall or stalled for a short period. Roughly 16% of stalls reached the timeout before expiry. For direct reclaim, the number of times stalled for each reason were 6624 reason=VMSCAN_THROTTLE_ISOLATED 93246 reason=VMSCAN_THROTTLE_NOPROGRESS 96934 reason=VMSCAN_THROTTLE_WRITEBACK The most common reason to stall was due to excessive pages tagged for immediate reclaim at the tail of the LRU followed by a failure to make forward. A relatively small number were due to too many pages isolated from the LRU by parallel threads For VMSCAN_THROTTLE_ISOLATED, the breakdown of delays was 9 usec_timeout=20000 usect_delayed=4000 reason=VMSCAN_THROTTLE_ISOLATED 12 usec_timeout=20000 usect_delayed=16000 reason=VMSCAN_THROTTLE_ISOLATED 83 usec_timeout=20000 usect_delayed=20000 reason=VMSCAN_THROTTLE_ISOLATED 6520 usec_timeout=20000 usect_delayed=0 reason=VMSCAN_THROTTLE_ISOLATED Most did not stall at all. A small number reached the timeout. For VMSCAN_THROTTLE_NOPROGRESS, the breakdown of stalls were all over the map 1 usec_timeout=500000 usect_delayed=324000 reason=VMSCAN_THROTTLE_NOPROGRESS 1 usec_timeout=500000 usect_delayed=332000 reason=VMSCAN_THROTTLE_NOPROGRESS 1 usec_timeout=500000 usect_delayed=348000 reason=VMSCAN_THROTTLE_NOPROGRESS 1 usec_timeout=500000 usect_delayed=360000 reason=VMSCAN_THROTTLE_NOPROGRESS 2 usec_timeout=500000 usect_delayed=228000 reason=VMSCAN_THROTTLE_NOPROGRESS 2 usec_timeout=500000 usect_delayed=260000 reason=VMSCAN_THROTTLE_NOPROGRESS 2 usec_timeout=500000 usect_delayed=340000 reason=VMSCAN_THROTTLE_NOPROGRESS 2 usec_timeout=500000 usect_delayed=364000 reason=VMSCAN_THROTTLE_NOPROGRESS 2 usec_timeout=500000 usect_delayed=372000 reason=VMSCAN_THROTTLE_NOPROGRESS 2 usec_timeout=500000 usect_delayed=428000 reason=VMSCAN_THROTTLE_NOPROGRESS 2 usec_timeout=500000 usect_delayed=460000 reason=VMSCAN_THROTTLE_NOPROGRESS 2 usec_timeout=500000 usect_delayed=464000 reason=VMSCAN_THROTTLE_NOPROGRESS 3 usec_timeout=500000 usect_delayed=244000 reason=VMSCAN_THROTTLE_NOPROGRESS 3 usec_timeout=500000 usect_delayed=252000 reason=VMSCAN_THROTTLE_NOPROGRESS 3 usec_timeout=500000 usect_delayed=272000 reason=VMSCAN_THROTTLE_NOPROGRESS 4 usec_timeout=500000 usect_delayed=188000 reason=VMSCAN_THROTTLE_NOPROGRESS 4 usec_timeout=500000 usect_delayed=268000 reason=VMSCAN_THROTTLE_NOPROGRESS 4 usec_timeout=500000 usect_delayed=328000 reason=VMSCAN_THROTTLE_NOPROGRESS 4 usec_timeout=500000 usect_delayed=380000 reason=VMSCAN_THROTTLE_NOPROGRESS 4 usec_timeout=500000 usect_delayed=392000 reason=VMSCAN_THROTTLE_NOPROGRESS 4 usec_timeout=500000 usect_delayed=432000 reason=VMSCAN_THROTTLE_NOPROGRESS 5 usec_timeout=500000 usect_delayed=204000 reason=VMSCAN_THROTTLE_NOPROGRESS 5 usec_timeout=500000 usect_delayed=220000 reason=VMSCAN_THROTTLE_NOPROGRESS 5 usec_timeout=500000 usect_delayed=412000 reason=VMSCAN_THROTTLE_NOPROGRESS 5 usec_timeout=500000 usect_delayed=436000 reason=VMSCAN_THROTTLE_NOPROGRESS 6 usec_timeout=500000 usect_delayed=488000 reason=VMSCAN_THROTTLE_NOPROGRESS 7 usec_timeout=500000 usect_delayed=212000 reason=VMSCAN_THROTTLE_NOPROGRESS 7 usec_timeout=500000 usect_delayed=300000 reason=VMSCAN_THROTTLE_NOPROGRESS 7 usec_timeout=500000 usect_delayed=316000 reason=VMSCAN_THROTTLE_NOPROGRESS 7 usec_timeout=500000 usect_delayed=472000 reason=VMSCAN_THROTTLE_NOPROGRESS 8 usec_timeout=500000 usect_delayed=248000 reason=VMSCAN_THROTTLE_NOPROGRESS 8 usec_timeout=500000 usect_delayed=356000 reason=VMSCAN_THROTTLE_NOPROGRESS 8 usec_timeout=500000 usect_delayed=456000 reason=VMSCAN_THROTTLE_NOPROGRESS 9 usec_timeout=500000 usect_delayed=124000 reason=VMSCAN_THROTTLE_NOPROGRESS 9 usec_timeout=500000 usect_delayed=376000 reason=VMSCAN_THROTTLE_NOPROGRESS 9 usec_timeout=500000 usect_delayed=484000 reason=VMSCAN_THROTTLE_NOPROGRESS 10 usec_timeout=500000 usect_delayed=172000 reason=VMSCAN_THROTTLE_NOPROGRESS 10 usec_timeout=500000 usect_delayed=420000 reason=VMSCAN_THROTTLE_NOPROGRESS 10 usec_timeout=500000 usect_delayed=452000 reason=VMSCAN_THROTTLE_NOPROGRESS 11 usec_timeout=500000 usect_delayed=256000 reason=VMSCAN_THROTTLE_NOPROGRESS 12 usec_timeout=500000 usect_delayed=112000 reason=VMSCAN_THROTTLE_NOPROGRESS 12 usec_timeout=500000 usect_delayed=116000 reason=VMSCAN_THROTTLE_NOPROGRESS 12 usec_timeout=500000 usect_delayed=144000 reason=VMSCAN_THROTTLE_NOPROGRESS 12 usec_timeout=500000 usect_delayed=152000 reason=VMSCAN_THROTTLE_NOPROGRESS 12 usec_timeout=500000 usect_delayed=264000 reason=VMSCAN_THROTTLE_NOPROGRESS 12 usec_timeout=500000 usect_delayed=384000 reason=VMSCAN_THROTTLE_NOPROGRESS 12 usec_timeout=500000 usect_delayed=424000 reason=VMSCAN_THROTTLE_NOPROGRESS 12 usec_timeout=500000 usect_delayed=492000 reason=VMSCAN_THROTTLE_NOPROGRESS 13 usec_timeout=500000 usect_delayed=184000 reason=VMSCAN_THROTTLE_NOPROGRESS 13 usec_timeout=500000 usect_delayed=444000 reason=VMSCAN_THROTTLE_NOPROGRESS 14 usec_timeout=500000 usect_delayed=308000 reason=VMSCAN_THROTTLE_NOPROGRESS 14 usec_timeout=500000 usect_delayed=440000 reason=VMSCAN_THROTTLE_NOPROGRESS 14 usec_timeout=500000 usect_delayed=476000 reason=VMSCAN_THROTTLE_NOPROGRESS 16 usec_timeout=500000 usect_delayed=140000 reason=VMSCAN_THROTTLE_NOPROGRESS 17 usec_timeout=500000 usect_delayed=232000 reason=VMSCAN_THROTTLE_NOPROGRESS 17 usec_timeout=500000 usect_delayed=240000 reason=VMSCAN_THROTTLE_NOPROGRESS 17 usec_timeout=500000 usect_delayed=280000 reason=VMSCAN_THROTTLE_NOPROGRESS 18 usec_timeout=500000 usect_delayed=404000 reason=VMSCAN_THROTTLE_NOPROGRESS 20 usec_timeout=500000 usect_delayed=148000 reason=VMSCAN_THROTTLE_NOPROGRESS 20 usec_timeout=500000 usect_delayed=216000 reason=VMSCAN_THROTTLE_NOPROGRESS 20 usec_timeout=500000 usect_delayed=468000 reason=VMSCAN_THROTTLE_NOPROGRESS 21 usec_timeout=500000 usect_delayed=448000 reason=VMSCAN_THROTTLE_NOPROGRESS 23 usec_timeout=500000 usect_delayed=168000 reason=VMSCAN_THROTTLE_NOPROGRESS 23 usec_timeout=500000 usect_delayed=296000 reason=VMSCAN_THROTTLE_NOPROGRESS 25 usec_timeout=500000 usect_delayed=132000 reason=VMSCAN_THROTTLE_NOPROGRESS 25 usec_timeout=500000 usect_delayed=352000 reason=VMSCAN_THROTTLE_NOPROGRESS 26 usec_timeout=500000 usect_delayed=180000 reason=VMSCAN_THROTTLE_NOPROGRESS 27 usec_timeout=500000 usect_delayed=284000 reason=VMSCAN_THROTTLE_NOPROGRESS 28 usec_timeout=500000 usect_delayed=164000 reason=VMSCAN_THROTTLE_NOPROGRESS 29 usec_timeout=500000 usect_delayed=136000 reason=VMSCAN_THROTTLE_NOPROGRESS 30 usec_timeout=500000 usect_delayed=200000 reason=VMSCAN_THROTTLE_NOPROGRESS 30 usec_timeout=500000 usect_delayed=400000 reason=VMSCAN_THROTTLE_NOPROGRESS 31 usec_timeout=500000 usect_delayed=196000 reason=VMSCAN_THROTTLE_NOPROGRESS 32 usec_timeout=500000 usect_delayed=156000 reason=VMSCAN_THROTTLE_NOPROGRESS 33 usec_timeout=500000 usect_delayed=224000 reason=VMSCAN_THROTTLE_NOPROGRESS 35 usec_timeout=500000 usect_delayed=128000 reason=VMSCAN_THROTTLE_NOPROGRESS 35 usec_timeout=500000 usect_delayed=176000 reason=VMSCAN_THROTTLE_NOPROGRESS 36 usec_timeout=500000 usect_delayed=368000 reason=VMSCAN_THROTTLE_NOPROGRESS 36 usec_timeout=500000 usect_delayed=496000 reason=VMSCAN_THROTTLE_NOPROGRESS 37 usec_timeout=500000 usect_delayed=312000 reason=VMSCAN_THROTTLE_NOPROGRESS 38 usec_timeout=500000 usect_delayed=304000 reason=VMSCAN_THROTTLE_NOPROGRESS 40 usec_timeout=500000 usect_delayed=288000 reason=VMSCAN_THROTTLE_NOPROGRESS 43 usec_timeout=500000 usect_delayed=408000 reason=VMSCAN_THROTTLE_NOPROGRESS 55 usec_timeout=500000 usect_delayed=416000 reason=VMSCAN_THROTTLE_NOPROGRESS 56 usec_timeout=500000 usect_delayed=76000 reason=VMSCAN_THROTTLE_NOPROGRESS 58 usec_timeout=500000 usect_delayed=120000 reason=VMSCAN_THROTTLE_NOPROGRESS 59 usec_timeout=500000 usect_delayed=208000 reason=VMSCAN_THROTTLE_NOPROGRESS 61 usec_timeout=500000 usect_delayed=68000 reason=VMSCAN_THROTTLE_NOPROGRESS 71 usec_timeout=500000 usect_delayed=192000 reason=VMSCAN_THROTTLE_NOPROGRESS 71 usec_timeout=500000 usect_delayed=480000 reason=VMSCAN_THROTTLE_NOPROGRESS 79 usec_timeout=500000 usect_delayed=60000 reason=VMSCAN_THROTTLE_NOPROGRESS 82 usec_timeout=500000 usect_delayed=320000 reason=VMSCAN_THROTTLE_NOPROGRESS 82 usec_timeout=500000 usect_delayed=92000 reason=VMSCAN_THROTTLE_NOPROGRESS 85 usec_timeout=500000 usect_delayed=64000 reason=VMSCAN_THROTTLE_NOPROGRESS 85 usec_timeout=500000 usect_delayed=80000 reason=VMSCAN_THROTTLE_NOPROGRESS 88 usec_timeout=500000 usect_delayed=84000 reason=VMSCAN_THROTTLE_NOPROGRESS 90 usec_timeout=500000 usect_delayed=160000 reason=VMSCAN_THROTTLE_NOPROGRESS 90 usec_timeout=500000 usect_delayed=292000 reason=VMSCAN_THROTTLE_NOPROGRESS 94 usec_timeout=500000 usect_delayed=56000 reason=VMSCAN_THROTTLE_NOPROGRESS 118 usec_timeout=500000 usect_delayed=88000 reason=VMSCAN_THROTTLE_NOPROGRESS 119 usec_timeout=500000 usect_delayed=72000 reason=VMSCAN_THROTTLE_NOPROGRESS 126 usec_timeout=500000 usect_delayed=108000 reason=VMSCAN_THROTTLE_NOPROGRESS 146 usec_timeout=500000 usect_delayed=52000 reason=VMSCAN_THROTTLE_NOPROGRESS 148 usec_timeout=500000 usect_delayed=36000 reason=VMSCAN_THROTTLE_NOPROGRESS 148 usec_timeout=500000 usect_delayed=48000 reason=VMSCAN_THROTTLE_NOPROGRESS 159 usec_timeout=500000 usect_delayed=28000 reason=VMSCAN_THROTTLE_NOPROGRESS 178 usec_timeout=500000 usect_delayed=44000 reason=VMSCAN_THROTTLE_NOPROGRESS 183 usec_timeout=500000 usect_delayed=40000 reason=VMSCAN_THROTTLE_NOPROGRESS 237 usec_timeout=500000 usect_delayed=100000 reason=VMSCAN_THROTTLE_NOPROGRESS 266 usec_timeout=500000 usect_delayed=32000 reason=VMSCAN_THROTTLE_NOPROGRESS 313 usec_timeout=500000 usect_delayed=24000 reason=VMSCAN_THROTTLE_NOPROGRESS 347 usec_timeout=500000 usect_delayed=96000 reason=VMSCAN_THROTTLE_NOPROGRESS 470 usec_timeout=500000 usect_delayed=20000 reason=VMSCAN_THROTTLE_NOPROGRESS 559 usec_timeout=500000 usect_delayed=16000 reason=VMSCAN_THROTTLE_NOPROGRESS 964 usec_timeout=500000 usect_delayed=12000 reason=VMSCAN_THROTTLE_NOPROGRESS 2001 usec_timeout=500000 usect_delayed=104000 reason=VMSCAN_THROTTLE_NOPROGRESS 2447 usec_timeout=500000 usect_delayed=8000 reason=VMSCAN_THROTTLE_NOPROGRESS 7888 usec_timeout=500000 usect_delayed=4000 reason=VMSCAN_THROTTLE_NOPROGRESS 22727 usec_timeout=500000 usect_delayed=0 reason=VMSCAN_THROTTLE_NOPROGRESS 51305 usec_timeout=500000 usect_delayed=500000 reason=VMSCAN_THROTTLE_NOPROGRESS The full timeout is often hit but a large number also do not stall at all. The remainder slept a little allowing other reclaim tasks to make progress. While this timeout could be further increased, it could also negatively impact worst-case behaviour when there is no prioritisation of what task should make progress. For VMSCAN_THROTTLE_WRITEBACK, the breakdown was 1 usec_timeout=100000 usect_delayed=44000 reason=VMSCAN_THROTTLE_WRITEBACK 2 usec_timeout=100000 usect_delayed=76000 reason=VMSCAN_THROTTLE_WRITEBACK 3 usec_timeout=100000 usect_delayed=80000 reason=VMSCAN_THROTTLE_WRITEBACK 5 usec_timeout=100000 usect_delayed=48000 reason=VMSCAN_THROTTLE_WRITEBACK 5 usec_timeout=100000 usect_delayed=84000 reason=VMSCAN_THROTTLE_WRITEBACK 6 usec_timeout=100000 usect_delayed=72000 reason=VMSCAN_THROTTLE_WRITEBACK 7 usec_timeout=100000 usect_delayed=88000 reason=VMSCAN_THROTTLE_WRITEBACK 11 usec_timeout=100000 usect_delayed=56000 reason=VMSCAN_THROTTLE_WRITEBACK 12 usec_timeout=100000 usect_delayed=64000 reason=VMSCAN_THROTTLE_WRITEBACK 16 usec_timeout=100000 usect_delayed=92000 reason=VMSCAN_THROTTLE_WRITEBACK 24 usec_timeout=100000 usect_delayed=68000 reason=VMSCAN_THROTTLE_WRITEBACK 28 usec_timeout=100000 usect_delayed=32000 reason=VMSCAN_THROTTLE_WRITEBACK 30 usec_timeout=100000 usect_delayed=60000 reason=VMSCAN_THROTTLE_WRITEBACK 30 usec_timeout=100000 usect_delayed=96000 reason=VMSCAN_THROTTLE_WRITEBACK 32 usec_timeout=100000 usect_delayed=52000 reason=VMSCAN_THROTTLE_WRITEBACK 42 usec_timeout=100000 usect_delayed=40000 reason=VMSCAN_THROTTLE_WRITEBACK 77 usec_timeout=100000 usect_delayed=28000 reason=VMSCAN_THROTTLE_WRITEBACK 99 usec_timeout=100000 usect_delayed=36000 reason=VMSCAN_THROTTLE_WRITEBACK 137 usec_timeout=100000 usect_delayed=24000 reason=VMSCAN_THROTTLE_WRITEBACK 190 usec_timeout=100000 usect_delayed=20000 reason=VMSCAN_THROTTLE_WRITEBACK 339 usec_timeout=100000 usect_delayed=16000 reason=VMSCAN_THROTTLE_WRITEBACK 518 usec_timeout=100000 usect_delayed=12000 reason=VMSCAN_THROTTLE_WRITEBACK 852 usec_timeout=100000 usect_delayed=8000 reason=VMSCAN_THROTTLE_WRITEBACK 3359 usec_timeout=100000 usect_delayed=4000 reason=VMSCAN_THROTTLE_WRITEBACK 7147 usec_timeout=100000 usect_delayed=0 reason=VMSCAN_THROTTLE_WRITEBACK 83962 usec_timeout=100000 usect_delayed=100000 reason=VMSCAN_THROTTLE_WRITEBACK The majority hit the timeout in direct reclaim context although a sizable number did not stall at all. This is very different to kswapd where only a tiny percentage of stalls due to writeback reached the timeout. Bottom line, the throttling appears to work and the wakeup events may limit worst case stalls. There might be some grounds for adjusting timeouts but it's likely futile as the worst-case scenarios depend on the workload, memory size and the speed of the storage. A better approach to improve the series further would be to prioritise tasks based on their rate of allocation with the caveat that it may be very expensive to track. This patch (of 5): Page reclaim throttles on wait_iff_congested under the following conditions: - kswapd is encountering pages under writeback and marked for immediate reclaim implying that pages are cycling through the LRU faster than pages can be cleaned. - Direct reclaim will stall if all dirty pages are backed by congested inodes. wait_iff_congested is almost completely broken with few exceptions. This patch adds a new node-based workqueue and tracks the number of throttled tasks and pages written back since throttling started. If enough pages belonging to the node are written back then the throttled tasks will wake early. If not, the throttled tasks sleeps until the timeout expires. [neilb@suse.de: Uninterruptible sleep and simpler wakeups] [hdanton@sina.com: Avoid race when reclaim starts] [vbabka@suse.cz: vmstat irq-safe api, clarifications] Link: https://lore.kernel.org/linux-mm/45d8b7a6-8548-65f5-cccf-9f451d4ae3d4@kernel.dk/ [1] Link: https://lkml.kernel.org/r/20211022144651.19914-1-mgorman@techsingularity.net Link: https://lkml.kernel.org/r/20211022144651.19914-2-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: NeilBrown <neilb@suse.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: "Darrick J . Wong" <djwong@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Rik van Riel <riel@surriel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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8ca1b5a4 |
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05-Nov-2021 |
Feng Tang <feng.tang@intel.com> |
mm/page_alloc: detect allocation forbidden by cpuset and bail out early There was a report that starting an Ubuntu in docker while using cpuset to bind it to movable nodes (a node only has movable zone, like a node for hotplug or a Persistent Memory node in normal usage) will fail due to memory allocation failure, and then OOM is involved and many other innocent processes got killed. It can be reproduced with command: $ docker run -it --rm --cpuset-mems 4 ubuntu:latest bash -c "grep Mems_allowed /proc/self/status" (where node 4 is a movable node) runc:[2:INIT] invoked oom-killer: gfp_mask=0x500cc2(GFP_HIGHUSER|__GFP_ACCOUNT), order=0, oom_score_adj=0 CPU: 8 PID: 8291 Comm: runc:[2:INIT] Tainted: G W I E 5.8.2-0.g71b519a-default #1 openSUSE Tumbleweed (unreleased) Hardware name: Dell Inc. PowerEdge R640/0PHYDR, BIOS 2.6.4 04/09/2020 Call Trace: dump_stack+0x6b/0x88 dump_header+0x4a/0x1e2 oom_kill_process.cold+0xb/0x10 out_of_memory.part.0+0xaf/0x230 out_of_memory+0x3d/0x80 __alloc_pages_slowpath.constprop.0+0x954/0xa20 __alloc_pages_nodemask+0x2d3/0x300 pipe_write+0x322/0x590 new_sync_write+0x196/0x1b0 vfs_write+0x1c3/0x1f0 ksys_write+0xa7/0xe0 do_syscall_64+0x52/0xd0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Mem-Info: active_anon:392832 inactive_anon:182 isolated_anon:0 active_file:68130 inactive_file:151527 isolated_file:0 unevictable:2701 dirty:0 writeback:7 slab_reclaimable:51418 slab_unreclaimable:116300 mapped:45825 shmem:735 pagetables:2540 bounce:0 free:159849484 free_pcp:73 free_cma:0 Node 4 active_anon:1448kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB all_unreclaimable? no Node 4 Movable free:130021408kB min:9140kB low:139160kB high:269180kB reserved_highatomic:0KB active_anon:1448kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:130023424kB managed:130023424kB mlocked:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:292kB local_pcp:84kB free_cma:0kB lowmem_reserve[]: 0 0 0 0 0 Node 4 Movable: 1*4kB (M) 0*8kB 0*16kB 1*32kB (M) 0*64kB 0*128kB 1*256kB (M) 1*512kB (M) 1*1024kB (M) 0*2048kB 31743*4096kB (M) = 130021156kB oom-kill:constraint=CONSTRAINT_CPUSET,nodemask=(null),cpuset=docker-9976a269caec812c134fa317f27487ee36e1129beba7278a463dd53e5fb9997b.scope,mems_allowed=4,global_oom,task_memcg=/system.slice/containerd.service,task=containerd,pid=4100,uid=0 Out of memory: Killed process 4100 (containerd) total-vm:4077036kB, anon-rss:51184kB, file-rss:26016kB, shmem-rss:0kB, UID:0 pgtables:676kB oom_score_adj:0 oom_reaper: reaped process 8248 (docker), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB oom_reaper: reaped process 2054 (node_exporter), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB oom_reaper: reaped process 1452 (systemd-journal), now anon-rss:0kB, file-rss:8564kB, shmem-rss:4kB oom_reaper: reaped process 2146 (munin-node), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB oom_reaper: reaped process 8291 (runc:[2:INIT]), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB The reason is that in this case, the target cpuset nodes only have movable zone, while the creation of an OS in docker sometimes needs to allocate memory in non-movable zones (dma/dma32/normal) like GFP_HIGHUSER, and the cpuset limit forbids the allocation, then out-of-memory killing is involved even when normal nodes and movable nodes both have many free memory. The OOM killer cannot help to resolve the situation as there is no usable memory for the request in the cpuset scope. The only reasonable measure to take is to fail the allocation right away and have the caller to deal with it. So add a check for cases like this in the slowpath of allocation, and bail out early returning NULL for the allocation. As page allocation is one of the hottest path in kernel, this check will hurt all users with sane cpuset configuration, add a static branch check and detect the abnormal config in cpuset memory binding setup so that the extra check cost in page allocation is not paid by everyone. [thanks to Micho Hocko and David Rientjes for suggesting not handling it inside OOM code, adding cpuset check, refining comments] Link: https://lkml.kernel.org/r/1632481657-68112-1-git-send-email-feng.tang@intel.com Signed-off-by: Feng Tang <feng.tang@intel.com> Suggested-by: Michal Hocko <mhocko@suse.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Zefan Li <lizefan.x@bytedance.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f1dc0db2 |
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05-Nov-2021 |
Rolf Eike Beer <eb@emlix.com> |
mm: use __pfn_to_section() instead of open coding it It is defined in the same file just a few lines above. Link: https://lkml.kernel.org/r/4598487.Rc0NezkW7i@mobilepool36.emlix.com Signed-off-by: Rolf Eike Beer <eb@emlix.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4b097002 |
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07-Sep-2021 |
David Hildenbrand <david@redhat.com> |
mm: track present early pages per zone Patch series "mm/memory_hotplug: "auto-movable" online policy and memory groups", v3. I. Goal The goal of this series is improving in-kernel auto-online support. It tackles the fundamental problems that: 1) We can create zone imbalances when onlining all memory blindly to ZONE_MOVABLE, in the worst case crashing the system. We have to know upfront how much memory we are going to hotplug such that we can safely enable auto-onlining of all hotplugged memory to ZONE_MOVABLE via "online_movable". This is far from practical and only applicable in limited setups -- like inside VMs under the RHV/oVirt hypervisor which will never hotplug more than 3 times the boot memory (and the limitation is only in place due to the Linux limitation). 2) We see more setups that implement dynamic VM resizing, hot(un)plugging memory to resize VM memory. In these setups, we might hotplug a lot of memory, but it might happen in various small steps in both directions (e.g., 2 GiB -> 8 GiB -> 4 GiB -> 16 GiB ...). virtio-mem is the primary driver of this upstream right now, performing such dynamic resizing NUMA-aware via multiple virtio-mem devices. Onlining all hotplugged memory to ZONE_NORMAL means we basically have no hotunplug guarantees. Onlining all to ZONE_MOVABLE means we can easily run into zone imbalances when growing a VM. We want a mixture, and we want as much memory as reasonable/configured in ZONE_MOVABLE. Details regarding zone imbalances can be found at [1]. 3) Memory devices consist of 1..X memory block devices, however, the kernel doesn't really track the relationship. Consequently, also user space has no idea. We want to make per-device decisions. As one example, for memory hotunplug it doesn't make sense to use a mixture of zones within a single DIMM: we want all MOVABLE if possible, otherwise all !MOVABLE, because any !MOVABLE part will easily block the whole DIMM from getting hotunplugged. As another example, virtio-mem operates on individual units that span 1..X memory blocks. Similar to a DIMM, we want a unit to either be all MOVABLE or !MOVABLE. A "unit" can be thought of like a DIMM, however, all units of a virtio-mem device logically belong together and are managed (added/removed) by a single driver. We want as much memory of a virtio-mem device to be MOVABLE as possible. 4) We want memory onlining to be done right from the kernel while adding memory, not triggered by user space via udev rules; for example, this is reqired for fast memory hotplug for drivers that add individual memory blocks, like virito-mem. We want a way to configure a policy in the kernel and avoid implementing advanced policies in user space. The auto-onlining support we have in the kernel is not sufficient. All we have is a) online everything MOVABLE (online_movable) b) online everything !MOVABLE (online_kernel) c) keep zones contiguous (online). This series allows configuring c) to mean instead "online movable if possible according to the coniguration, driven by a maximum MOVABLE:KERNEL ratio" -- a new onlining policy. II. Approach This series does 3 things: 1) Introduces the "auto-movable" online policy that initially operates on individual memory blocks only. It uses a maximum MOVABLE:KERNEL ratio to make a decision whether a memory block will be onlined to ZONE_MOVABLE or not. However, in the basic form, hotplugged KERNEL memory does not allow for more MOVABLE memory (details in the patches). CMA memory is treated like MOVABLE memory. 2) Introduces static (e.g., DIMM) and dynamic (e.g., virtio-mem) memory groups and uses group information to make decisions in the "auto-movable" online policy across memory blocks of a single memory device (modeled as memory group). More details can be found in patch #3 or in the DIMM example below. 3) Maximizes ZONE_MOVABLE memory within dynamic memory groups, by allowing ZONE_NORMAL memory within a dynamic memory group to allow for more ZONE_MOVABLE memory within the same memory group. The target use case is dynamic VM resizing using virtio-mem. See the virtio-mem example below. I remember that the basic idea of using a ratio to implement a policy in the kernel was once mentioned by Vitaly Kuznetsov, but I might be wrong (I lost the pointer to that discussion). For me, the main use case is using it along with virtio-mem (and DIMMs / ppc64 dlpar where necessary) for dynamic resizing of VMs, increasing the amount of memory we can hotunplug reliably again if we might eventually hotplug a lot of memory to a VM. III. Target Usage The target usage will be: 1) Linux boots with "mhp_default_online_type=offline" 2) User space (e.g., systemd unit) configures memory onlining (according to a config file and system properties), for example: * Setting memory_hotplug.online_policy=auto-movable * Setting memory_hotplug.auto_movable_ratio=301 * Setting memory_hotplug.auto_movable_numa_aware=true 3) User space enabled auto onlining via "echo online > /sys/devices/system/memory/auto_online_blocks" 4) User space triggers manual onlining of all already-offline memory blocks (go over offline memory blocks and set them to "online") IV. Example For DIMMs, hotplugging 4 GiB DIMMs to a 4 GiB VM with a configured ratio of 301% results in the following layout: Memory block 0-15: DMA32 (early) Memory block 32-47: Normal (early) Memory block 48-79: Movable (DIMM 0) Memory block 80-111: Movable (DIMM 1) Memory block 112-143: Movable (DIMM 2) Memory block 144-275: Normal (DIMM 3) Memory block 176-207: Normal (DIMM 4) ... all Normal (-> hotplugged Normal memory does not allow for more Movable memory) For virtio-mem, using a simple, single virtio-mem device with a 4 GiB VM will result in the following layout: Memory block 0-15: DMA32 (early) Memory block 32-47: Normal (early) Memory block 48-143: Movable (virtio-mem, first 12 GiB) Memory block 144: Normal (virtio-mem, next 128 MiB) Memory block 145-147: Movable (virtio-mem, next 384 MiB) Memory block 148: Normal (virtio-mem, next 128 MiB) Memory block 149-151: Movable (virtio-mem, next 384 MiB) ... Normal/Movable mixture as above (-> hotplugged Normal memory allows for more Movable memory within the same device) Which gives us maximum flexibility when dynamically growing/shrinking a VM in smaller steps. V. Doc Update I'll update the memory-hotplug.rst documentation, once the overhaul [1] is usptream. Until then, details can be found in patch #2. VI. Future Work 1) Use memory groups for ppc64 dlpar 2) Being able to specify a portion of (early) kernel memory that will be excluded from the ratio. Like "128 MiB globally/per node" are excluded. This might be helpful when starting VMs with extremely small memory footprint (e.g., 128 MiB) and hotplugging memory later -- not wanting the first hotplugged units getting onlined to ZONE_MOVABLE. One alternative would be a trigger to not consider ZONE_DMA memory in the ratio. We'll have to see if this is really rrequired. 3) Indicate to user space that MOVABLE might be a bad idea -- especially relevant when memory ballooning without support for balloon compaction is active. This patch (of 9): For implementing a new memory onlining policy, which determines when to online memory blocks to ZONE_MOVABLE semi-automatically, we need the number of present early (boot) pages -- present pages excluding hotplugged pages. Let's track these pages per zone. Pass a page instead of the zone to adjust_present_page_count(), similar as adjust_managed_page_count() and derive the zone from the page. It's worth noting that a memory block to be offlined/onlined is either completely "early" or "not early". add_memory() and friends can only add complete memory blocks and we only online/offline complete (individual) memory blocks. Link: https://lkml.kernel.org/r/20210806124715.17090-1-david@redhat.com Link: https://lkml.kernel.org/r/20210806124715.17090-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Marek Kedzierski <mkedzier@redhat.com> Cc: Hui Zhu <teawater@gmail.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mike Rapoport <rppt@kernel.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Len Brown <lenb@kernel.org> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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859a85dd |
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07-Sep-2021 |
Mike Rapoport <rppt@kernel.org> |
mm: remove pfn_valid_within() and CONFIG_HOLES_IN_ZONE Patch series "mm: remove pfn_valid_within() and CONFIG_HOLES_IN_ZONE". After recent updates to freeing unused parts of the memory map, no architecture can have holes in the memory map within a pageblock. This makes pfn_valid_within() check and CONFIG_HOLES_IN_ZONE configuration option redundant. The first patch removes them both in a mechanical way and the second patch simplifies memory_hotplug::test_pages_in_a_zone() that had pfn_valid_within() surrounded by more logic than simple if. This patch (of 2): After recent changes in freeing of the unused parts of the memory map and rework of pfn_valid() in arm and arm64 there are no architectures that can have holes in the memory map within a pageblock and so nothing can enable CONFIG_HOLES_IN_ZONE which guards non trivial implementation of pfn_valid_within(). With that, pfn_valid_within() is always hardwired to 1 and can be completely removed. Remove calls to pfn_valid_within() and CONFIG_HOLES_IN_ZONE. Link: https://lkml.kernel.org/r/20210713080035.7464-1-rppt@kernel.org Link: https://lkml.kernel.org/r/20210713080035.7464-2-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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65d759c8 |
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02-Sep-2021 |
Charan Teja Reddy <charante@codeaurora.org> |
mm: compaction: support triggering of proactive compaction by user The proactive compaction[1] gets triggered for every 500msec and run compaction on the node for COMPACTION_HPAGE_ORDER (usually order-9) pages based on the value set to sysctl.compaction_proactiveness. Triggering the compaction for every 500msec in search of COMPACTION_HPAGE_ORDER pages is not needed for all applications, especially on the embedded system usecases which may have few MB's of RAM. Enabling the proactive compaction in its state will endup in running almost always on such systems. Other side, proactive compaction can still be very much useful for getting a set of higher order pages in some controllable manner(controlled by using the sysctl.compaction_proactiveness). So, on systems where enabling the proactive compaction always may proove not required, can trigger the same from user space on write to its sysctl interface. As an example, say app launcher decide to launch the memory heavy application which can be launched fast if it gets more higher order pages thus launcher can prepare the system in advance by triggering the proactive compaction from userspace. This triggering of proactive compaction is done on a write to sysctl.compaction_proactiveness by user. [1]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=facdaa917c4d5a376d09d25865f5a863f906234a [akpm@linux-foundation.org: tweak vm.rst, per Mike] Link: https://lkml.kernel.org/r/1627653207-12317-1-git-send-email-charante@codeaurora.org Signed-off-by: Charan Teja Reddy <charante@codeaurora.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Rafael Aquini <aquini@redhat.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Nitin Gupta <nigupta@nvidia.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Vinayak Menon <vinmenon@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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01c8d337 |
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02-Sep-2021 |
Naoya Horiguchi <naoya.horiguchi@nec.com> |
mm/sparse: set SECTION_NID_SHIFT to 6 Currently SECTION_NID_SHIFT is set to 3, which is incorrect because bit 3 and 4 can be overlapped by sub-field for early NID, and can be unexpectedly set on NUMA systems. There are a few non-critical issues related to this: - Having SECTION_TAINT_ZONE_DEVICE set for wrong sections forces pfn_to_online_page() through the slow path, but doesn't actually break the kernel. - A kdump generation tool like makedumpfile uses this field to calculate the physical address to read. So wrong bits can make the tool access to wrong address and fail to create kdump. This can be avoided by the tool, so it's not critical. To fix it, set SECTION_NID_SHIFT to 6 which is the minimum number of available bits of section flag field. Link: https://lkml.kernel.org/r/20210707045548.810271-1-naoya.horiguchi@linux.dev Fixes: 1f90a3477df3 ("mm: teach pfn_to_online_page() about ZONE_DEVICE section collisions") Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Reported-by: Kazuhito Hagio <k-hagio-ab@nec.com> Suggested-by: Dan Williams <dan.j.williams@intel.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Wang Wensheng <wangwensheng4@huawei.com> Cc: Rui Xiang <rui.xiang@huawei.com> Cc: Kazu <k-hagio-ab@nec.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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11e02d37 |
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02-Sep-2021 |
Ohhoon Kwon <ohoono.kwon@samsung.com> |
mm: sparse: remove __section_nr() function As the last users of __section_nr() are gone, let's remove unused function __section_nr(). Link: https://lkml.kernel.org/r/20210707150212.855-4-ohoono.kwon@samsung.com Signed-off-by: Ohhoon Kwon <ohoono.kwon@samsung.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Baoquan He <bhe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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351de44f |
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30-Jun-2021 |
Mel Gorman <mgorman@techsingularity.net> |
mm/swap: make NODE_DATA an inline function on CONFIG_FLATMEM make W=1 generates the following warning in mm/workingset.c for allnoconfig mm/workingset.c: In function `unpack_shadow': mm/workingset.c:201:15: warning: variable `nid' set but not used [-Wunused-but-set-variable] int memcgid, nid; ^~~ On FLATMEM, NODE_DATA returns a global pglist_data without dereferencing nid. Make the helper an inline function to suppress the warning, add type checking and to apply any side-effects in the parameter list. Link: https://lkml.kernel.org/r/20210520084809.8576-15-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Streetman <ddstreet@ieee.org> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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041711ce |
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30-Jun-2021 |
Zhen Lei <thunder.leizhen@huawei.com> |
mm: fix spelling mistakes Fix some spelling mistakes in comments: each having differents usage ==> each has a different usage statments ==> statements adresses ==> addresses aggresive ==> aggressive datas ==> data posion ==> poison higer ==> higher precisly ==> precisely wont ==> won't We moves tha ==> We move the endianess ==> endianness Link: https://lkml.kernel.org/r/20210519065853.7723-2-thunder.leizhen@huawei.com Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Reviewed-by: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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16c9afc7 |
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30-Jun-2021 |
Anshuman Khandual <anshuman.khandual@arm.com> |
arm64/mm: drop HAVE_ARCH_PFN_VALID CONFIG_SPARSEMEM_VMEMMAP is now the only available memory model on arm64 platforms and free_unused_memmap() would just return without creating any holes in the memmap mapping. There is no need for any special handling in pfn_valid() and HAVE_ARCH_PFN_VALID can just be dropped. This also moves the pfn upper bits sanity check into generic pfn_valid(). Link: https://lkml.kernel.org/r/1621947349-25421-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Mike Rapoport <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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51c656ae |
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30-Jun-2021 |
Mike Rapoport <rppt@kernel.org> |
include/linux/mmzone.h: add documentation for pfn_valid() Patch series "arm64: drop pfn_valid_within() and simplify pfn_valid()", v4. These patches aim to remove CONFIG_HOLES_IN_ZONE and essentially hardwire pfn_valid_within() to 1. The idea is to mark NOMAP pages as reserved in the memory map and restore the intended semantics of pfn_valid() to designate availability of struct page for a pfn. With this the core mm will be able to cope with the fact that it cannot use NOMAP pages and the holes created by NOMAP ranges within MAX_ORDER blocks will be treated correctly even without the need for pfn_valid_within. This patch (of 4): Add comment describing the semantics of pfn_valid() that clarifies that pfn_valid() only checks for availability of a memory map entry (i.e. struct page) for a PFN rather than availability of usable memory backing that PFN. The most "generic" version of pfn_valid() used by the configurations with SPARSEMEM enabled resides in include/linux/mmzone.h so this is the most suitable place for documentation about semantics of pfn_valid(). Link: https://lkml.kernel.org/r/20210511100550.28178-1-rppt@kernel.org Link: https://lkml.kernel.org/r/20210511100550.28178-2-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Suggested-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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44042b44 |
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28-Jun-2021 |
Mel Gorman <mgorman@techsingularity.net> |
mm/page_alloc: allow high-order pages to be stored on the per-cpu lists The per-cpu page allocator (PCP) only stores order-0 pages. This means that all THP and "cheap" high-order allocations including SLUB contends on the zone->lock. This patch extends the PCP allocator to store THP and "cheap" high-order pages. Note that struct per_cpu_pages increases in size to 256 bytes (4 cache lines) on x86-64. Note that this is not necessarily a universal performance win because of how it is implemented. High-order pages can cause pcp->high to be exceeded prematurely for lower-orders so for example, a large number of THP pages being freed could release order-0 pages from the PCP lists. Hence, much depends on the allocation/free pattern as observed by a single CPU to determine if caching helps or hurts a particular workload. That said, basic performance testing passed. The following is a netperf UDP_STREAM test which hits the relevant patches as some of the network allocations are high-order. netperf-udp 5.13.0-rc2 5.13.0-rc2 mm-pcpburst-v3r4 mm-pcphighorder-v1r7 Hmean send-64 261.46 ( 0.00%) 266.30 * 1.85%* Hmean send-128 516.35 ( 0.00%) 536.78 * 3.96%* Hmean send-256 1014.13 ( 0.00%) 1034.63 * 2.02%* Hmean send-1024 3907.65 ( 0.00%) 4046.11 * 3.54%* Hmean send-2048 7492.93 ( 0.00%) 7754.85 * 3.50%* Hmean send-3312 11410.04 ( 0.00%) 11772.32 * 3.18%* Hmean send-4096 13521.95 ( 0.00%) 13912.34 * 2.89%* Hmean send-8192 21660.50 ( 0.00%) 22730.72 * 4.94%* Hmean send-16384 31902.32 ( 0.00%) 32637.50 * 2.30%* Functionally, a patch like this is necessary to make bulk allocation of high-order pages work with similar performance to order-0 bulk allocations. The bulk allocator is not updated in this series as it would have to be determined by bulk allocation users how they want to track the order of pages allocated with the bulk allocator. Link: https://lkml.kernel.org/r/20210611135753.GC30378@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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43b02ba9 |
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28-Jun-2021 |
Mike Rapoport <rppt@kernel.org> |
mm: replace CONFIG_FLAT_NODE_MEM_MAP with CONFIG_FLATMEM After removal of the DISCONTIGMEM memory model the FLAT_NODE_MEM_MAP configuration option is equivalent to FLATMEM. Drop CONFIG_FLAT_NODE_MEM_MAP and use CONFIG_FLATMEM instead. Link: https://lkml.kernel.org/r/20210608091316.3622-10-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: David Hildenbrand <david@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matt Turner <mattst88@gmail.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a9ee6cf5 |
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28-Jun-2021 |
Mike Rapoport <rppt@kernel.org> |
mm: replace CONFIG_NEED_MULTIPLE_NODES with CONFIG_NUMA After removal of DISCINTIGMEM the NEED_MULTIPLE_NODES and NUMA configuration options are equivalent. Drop CONFIG_NEED_MULTIPLE_NODES and use CONFIG_NUMA instead. Done with $ sed -i 's/CONFIG_NEED_MULTIPLE_NODES/CONFIG_NUMA/' \ $(git grep -wl CONFIG_NEED_MULTIPLE_NODES) $ sed -i 's/NEED_MULTIPLE_NODES/NUMA/' \ $(git grep -wl NEED_MULTIPLE_NODES) with manual tweaks afterwards. [rppt@linux.ibm.com: fix arm boot crash] Link: https://lkml.kernel.org/r/YMj9vHhHOiCVN4BF@linux.ibm.com Link: https://lkml.kernel.org/r/20210608091316.3622-9-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: David Hildenbrand <david@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matt Turner <mattst88@gmail.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bb1c50d3 |
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28-Jun-2021 |
Mike Rapoport <rppt@kernel.org> |
mm: remove CONFIG_DISCONTIGMEM There are no architectures that support DISCONTIGMEM left. Remove the configuration option and the dead code it was guarding in the generic memory management code. Link: https://lkml.kernel.org/r/20210608091316.3622-6-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: David Hildenbrand <david@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matt Turner <mattst88@gmail.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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777c00f5 |
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28-Jun-2021 |
Dong Aisheng <aisheng.dong@nxp.com> |
mm: drop SECTION_SHIFT in code comments Actually SECTIONS_SHIFT is used in the kernel code, so the code comments is strictly incorrect. And since commit bbeae5b05ef6 ("mm: move page flags layout to separate header"), SECTIONS_SHIFT definition has been moved to include/linux/page-flags-layout.h, since code itself looks quite straighforward, instead of moving the code comment into the new place as well, we just simply remove it. This also fixed a checkpatch complain derived from the original code: WARNING: please, no space before tabs + * SECTIONS_SHIFT ^I^I#bits space required to store a section #$ Link: https://lkml.kernel.org/r/20210531091908.1738465-2-aisheng.dong@nxp.com Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com> Suggested-by: Yu Zhao <yuzhao@google.com> Reviewed-by: Yu Zhao <yuzhao@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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74f44822 |
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28-Jun-2021 |
Mel Gorman <mgorman@techsingularity.net> |
mm/page_alloc: introduce vm.percpu_pagelist_high_fraction This introduces a new sysctl vm.percpu_pagelist_high_fraction. It is similar to the old vm.percpu_pagelist_fraction. The old sysctl increased both pcp->batch and pcp->high with the higher pcp->high potentially reducing zone->lock contention. However, the higher pcp->batch value also potentially increased allocation latency while the PCP was refilled. This sysctl only adjusts pcp->high so that zone->lock contention is potentially reduced but allocation latency during a PCP refill remains the same. # grep -E "high:|batch" /proc/zoneinfo | tail -2 high: 649 batch: 63 # sysctl vm.percpu_pagelist_high_fraction=8 # grep -E "high:|batch" /proc/zoneinfo | tail -2 high: 35071 batch: 63 # sysctl vm.percpu_pagelist_high_fraction=64 high: 4383 batch: 63 # sysctl vm.percpu_pagelist_high_fraction=0 high: 649 batch: 63 [mgorman@techsingularity.net: fix documentation] Link: https://lkml.kernel.org/r/20210528151010.GQ30378@techsingularity.net Link: https://lkml.kernel.org/r/20210525080119.5455-7-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hdanton@sina.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c49c2c47 |
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28-Jun-2021 |
Mel Gorman <mgorman@techsingularity.net> |
mm/page_alloc: limit the number of pages on PCP lists when reclaim is active When kswapd is active then direct reclaim is potentially active. In either case, it is possible that a zone would be balanced if pages were not trapped on PCP lists. Instead of draining remote pages, simply limit the size of the PCP lists while kswapd is active. Link: https://lkml.kernel.org/r/20210525080119.5455-6-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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3b12e7e9 |
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28-Jun-2021 |
Mel Gorman <mgorman@techsingularity.net> |
mm/page_alloc: scale the number of pages that are batch freed When a task is freeing a large number of order-0 pages, it may acquire the zone->lock multiple times freeing pages in batches. This may unnecessarily contend on the zone lock when freeing very large number of pages. This patch adapts the size of the batch based on the recent pattern to scale the batch size for subsequent frees. As the machines I used were not large enough to test this are not large enough to illustrate a problem, a debugging patch shows patterns like the following (slightly editted for clarity) Baseline vanilla kernel time-unmap-14426 [...] free_pcppages_bulk: free 63 count 378 high 378 time-unmap-14426 [...] free_pcppages_bulk: free 63 count 378 high 378 time-unmap-14426 [...] free_pcppages_bulk: free 63 count 378 high 378 time-unmap-14426 [...] free_pcppages_bulk: free 63 count 378 high 378 time-unmap-14426 [...] free_pcppages_bulk: free 63 count 378 high 378 With patches time-unmap-7724 [...] free_pcppages_bulk: free 126 count 814 high 814 time-unmap-7724 [...] free_pcppages_bulk: free 252 count 814 high 814 time-unmap-7724 [...] free_pcppages_bulk: free 504 count 814 high 814 time-unmap-7724 [...] free_pcppages_bulk: free 751 count 814 high 814 time-unmap-7724 [...] free_pcppages_bulk: free 751 count 814 high 814 Link: https://lkml.kernel.org/r/20210525080119.5455-5-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hdanton@sina.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bbbecb35 |
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28-Jun-2021 |
Mel Gorman <mgorman@techsingularity.net> |
mm/page_alloc: delete vm.percpu_pagelist_fraction Patch series "Calculate pcp->high based on zone sizes and active CPUs", v2. The per-cpu page allocator (PCP) is meant to reduce contention on the zone lock but the sizing of batch and high is archaic and neither takes the zone size into account or the number of CPUs local to a zone. With larger zones and more CPUs per node, the contention is getting worse. Furthermore, the fact that vm.percpu_pagelist_fraction adjusts both batch and high values means that the sysctl can reduce zone lock contention but also increase allocation latencies. This series disassociates pcp->high from pcp->batch and then scales pcp->high based on the size of the local zone with limited impact to reclaim and accounting for active CPUs but leaves pcp->batch static. It also adapts the number of pages that can be on the pcp list based on recent freeing patterns. The motivation is partially to adjust to larger memory sizes but is also driven by the fact that large batches of page freeing via release_pages() often shows zone contention as a major part of the problem. Another is a bug report based on an older kernel where a multi-terabyte process can takes several minutes to exit. A workaround was to use vm.percpu_pagelist_fraction to increase the pcp->high value but testing indicated that a production workload could not use the same values because of an increase in allocation latencies. Unfortunately, I cannot reproduce this test case myself as the multi-terabyte machines are in active use but it should alleviate the problem. The series aims to address both and partially acts as a pre-requisite. pcp only works with order-0 which is useless for SLUB (when using high orders) and THP (unconditionally). To store high-order pages on PCP, the pcp->high values need to be increased first. This patch (of 6): The vm.percpu_pagelist_fraction is used to increase the batch and high limits for the per-cpu page allocator (PCP). The intent behind the sysctl is to reduce zone lock acquisition when allocating/freeing pages but it has a problem. While it can decrease contention, it can also increase latency on the allocation side due to unreasonably large batch sizes. This leads to games where an administrator adjusts percpu_pagelist_fraction on the fly to work around contention and allocation latency problems. This series aims to alleviate the problems with zone lock contention while avoiding the allocation-side latency problems. For the purposes of review, it's easier to remove this sysctl now and reintroduce a similar sysctl later in the series that deals only with pcp->high. Link: https://lkml.kernel.org/r/20210525080119.5455-1-mgorman@techsingularity.net Link: https://lkml.kernel.org/r/20210525080119.5455-2-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hdanton@sina.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f19298b9 |
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28-Jun-2021 |
Mel Gorman <mgorman@techsingularity.net> |
mm/vmstat: convert NUMA statistics to basic NUMA counters NUMA statistics are maintained on the zone level for hits, misses, foreign etc but nothing relies on them being perfectly accurate for functional correctness. The counters are used by userspace to get a general overview of a workloads NUMA behaviour but the page allocator incurs a high cost to maintain perfect accuracy similar to what is required for a vmstat like NR_FREE_PAGES. There even is a sysctl vm.numa_stat to allow userspace to turn off the collection of NUMA statistics like NUMA_HIT. This patch converts NUMA_HIT and friends to be NUMA events with similar accuracy to VM events. There is a possibility that slight errors will be introduced but the overall trend as seen by userspace will be similar. The counters are no longer updated from vmstat_refresh context as it is unnecessary overhead for counters that may never be read by userspace. Note that counters could be maintained at the node level to save space but it would have a user-visible impact due to /proc/zoneinfo. [lkp@intel.com: Fix misplaced closing brace for !CONFIG_NUMA] Link: https://lkml.kernel.org/r/20210512095458.30632-4-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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dbbee9d5 |
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28-Jun-2021 |
Mel Gorman <mgorman@techsingularity.net> |
mm/page_alloc: convert per-cpu list protection to local_lock There is a lack of clarity of what exactly local_irq_save/local_irq_restore protects in page_alloc.c . It conflates the protection of per-cpu page allocation structures with per-cpu vmstat deltas. This patch protects the PCP structure using local_lock which for most configurations is identical to IRQ enabling/disabling. The scope of the lock is still wider than it should be but this is decreased later. It is possible for the local_lock to be embedded safely within struct per_cpu_pages but it adds complexity to free_unref_page_list. [akpm@linux-foundation.org: coding style fixes] [mgorman@techsingularity.net: work around a pahole limitation with zero-sized struct pagesets] Link: https://lkml.kernel.org/r/20210526080741.GW30378@techsingularity.net [lkp@intel.com: Make pagesets static] Link: https://lkml.kernel.org/r/20210512095458.30632-3-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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28f836b6 |
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28-Jun-2021 |
Mel Gorman <mgorman@techsingularity.net> |
mm/page_alloc: split per cpu page lists and zone stats The PCP (per-cpu page allocator in page_alloc.c) shares locking requirements with vmstat and the zone lock which is inconvenient and causes some issues. For example, the PCP list and vmstat share the same per-cpu space meaning that it's possible that vmstat updates dirty cache lines holding per-cpu lists across CPUs unless padding is used. Second, PREEMPT_RT does not want to disable IRQs for too long in the page allocator. This series splits the locking requirements and uses locks types more suitable for PREEMPT_RT, reduces the time when special locking is required for stats and reduces the time when IRQs need to be disabled on !PREEMPT_RT kernels. Why local_lock? PREEMPT_RT considers the following sequence to be unsafe as documented in Documentation/locking/locktypes.rst local_irq_disable(); spin_lock(&lock); The pcp allocator has this sequence for rmqueue_pcplist (local_irq_save) -> __rmqueue_pcplist -> rmqueue_bulk (spin_lock). While it's possible to separate this out, it generally means there are points where we enable IRQs and reenable them again immediately. To prevent a migration and the per-cpu pointer going stale, migrate_disable is also needed. That is a custom lock that is similar, but worse, than local_lock. Furthermore, on PREEMPT_RT, it's undesirable to leave IRQs disabled for too long. By converting to local_lock which disables migration on PREEMPT_RT, the locking requirements can be separated and start moving the protections for PCP, stats and the zone lock to PREEMPT_RT-safe equivalent locking. As a bonus, local_lock also means that PROVE_LOCKING does something useful. After that, it's obvious that zone_statistics incurs too much overhead and leaves IRQs disabled for longer than necessary on !PREEMPT_RT kernels. zone_statistics uses perfectly accurate counters requiring IRQs be disabled for parallel RMW sequences when inaccurate ones like vm_events would do. The series makes the NUMA statistics (NUMA_HIT and friends) inaccurate counters that then require no special protection on !PREEMPT_RT. The bulk page allocator can then do stat updates in bulk with IRQs enabled which should improve the efficiency. Technically, this could have been done without the local_lock and vmstat conversion work and the order simply reflects the timing of when different series were implemented. Finally, there are places where we conflate IRQs being disabled for the PCP with the IRQ-safe zone spinlock. The remainder of the series reduces the scope of what is protected by disabled IRQs on !PREEMPT_RT kernels. By the end of the series, page_alloc.c does not call local_irq_save so the locking scope is a bit clearer. The one exception is that modifying NR_FREE_PAGES still happens in places where it's known the IRQs are disabled as it's harmless for PREEMPT_RT and would be expensive to split the locking there. No performance data is included because despite the overhead of the stats, it's within the noise for most workloads on !PREEMPT_RT. However, Jesper Dangaard Brouer ran a page allocation microbenchmark on a E5-1650 v4 @ 3.60GHz CPU on the first version of this series. Focusing on the array variant of the bulk page allocator reveals the following. (CPU: Intel(R) Xeon(R) CPU E5-1650 v4 @ 3.60GHz) ARRAY variant: time_bulk_page_alloc_free_array: step=bulk size Baseline Patched 1 56.383 54.225 (+3.83%) 2 40.047 35.492 (+11.38%) 3 37.339 32.643 (+12.58%) 4 35.578 30.992 (+12.89%) 8 33.592 29.606 (+11.87%) 16 32.362 28.532 (+11.85%) 32 31.476 27.728 (+11.91%) 64 30.633 27.252 (+11.04%) 128 30.596 27.090 (+11.46%) While this is a positive outcome, the series is more likely to be interesting to the RT people in terms of getting parts of the PREEMPT_RT tree into mainline. This patch (of 9): The per-cpu page allocator lists and the per-cpu vmstat deltas are stored in the same struct per_cpu_pages even though vmstats have no direct impact on the per-cpu page lists. This is inconsistent because the vmstats for a node are stored on a dedicated structure. The bigger issue is that the per_cpu_pages structure is not cache-aligned and stat updates either cache conflict with adjacent per-cpu lists incurring a runtime cost or padding is required incurring a memory cost. This patch splits the per-cpu pagelists and the vmstat deltas into separate structures. It's mostly a mechanical conversion but some variable renaming is done to clearly distinguish the per-cpu pages structure (pcp) from the vmstats (pzstats). Superficially, this appears to increase the size of the per_cpu_pages structure but the movement of expire fills a structure hole so there is no impact overall. [mgorman@techsingularity.net: make it W=1 cleaner] Link: https://lkml.kernel.org/r/20210514144622.GA3735@techsingularity.net [mgorman@techsingularity.net: make it W=1 even cleaner] Link: https://lkml.kernel.org/r/20210516140705.GB3735@techsingularity.net [lkp@intel.com: check struct per_cpu_zonestat has a non-zero size] [vbabka@suse.cz: Init zone->per_cpu_zonestats properly] Link: https://lkml.kernel.org/r/20210512095458.30632-1-mgorman@techsingularity.net Link: https://lkml.kernel.org/r/20210512095458.30632-2-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b19bd1c9 |
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28-Jun-2021 |
Mike Rapoport <rppt@kernel.org> |
mm/mmzone.h: simplify is_highmem_idx() There is a lot of historical ifdefery in is_highmem_idx() and its helper zone_movable_is_highmem() that was required because of two different paths for nodes and zones initialization that were selected at compile time. Until commit 3f08a302f533 ("mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option") the movable_zone variable was only available for configurations that had CONFIG_HAVE_MEMBLOCK_NODE_MAP enabled so the test in zone_movable_is_highmem() used that variable only for such configurations. For other configurations the test checked if the index of ZONE_MOVABLE was greater by 1 than the index of ZONE_HIGMEM and then movable zone was considered a highmem zone. Needless to say, ZONE_MOVABLE - 1 equals ZONE_HIGHMEM by definition when CONFIG_HIGHMEM=y. Commit 3f08a302f533 ("mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option") made movable_zone variable always available. Since this variable is set to ZONE_HIGHMEM if CONFIG_HIGHMEM is enabled and highmem zone is populated, it is enough to check whether zone_idx == ZONE_MOVABLE && movable_zone == ZONE_HIGMEM to test if zone index points to a highmem zone. Remove zone_movable_is_highmem() that is not used anywhere except is_highmem_idx() and use the test above in is_highmem_idx() instead. Link: https://lkml.kernel.org/r/20210426141927.1314326-3-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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cb152a1a |
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06-May-2021 |
Shijie Luo <luoshijie1@huawei.com> |
mm: fix some typos and code style problems fix some typos and code style problems in mm. gfp.h: s/MAXNODES/MAX_NUMNODES mmzone.h: s/then/than rmap.c: s/__vma_split()/__vma_adjust() swap.c: s/__mod_zone_page_stat/__mod_zone_page_state, s/is is/is swap_state.c: s/whoes/whose z3fold.c: code style problem fix in z3fold_unregister_migration zsmalloc.c: s/of/or, s/give/given Link: https://lkml.kernel.org/r/20210419083057.64820-1-luoshijie1@huawei.com Signed-off-by: Shijie Luo <luoshijie1@huawei.com> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a08a2ae3 |
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04-May-2021 |
Oscar Salvador <osalvador@suse.de> |
mm,memory_hotplug: allocate memmap from the added memory range Physical memory hotadd has to allocate a memmap (struct page array) for the newly added memory section. Currently, alloc_pages_node() is used for those allocations. This has some disadvantages: a) an existing memory is consumed for that purpose (eg: ~2MB per 128MB memory section on x86_64) This can even lead to extreme cases where system goes OOM because the physically hotplugged memory depletes the available memory before it is onlined. b) if the whole node is movable then we have off-node struct pages which has performance drawbacks. c) It might be there are no PMD_ALIGNED chunks so memmap array gets populated with base pages. This can be improved when CONFIG_SPARSEMEM_VMEMMAP is enabled. Vmemap page tables can map arbitrary memory. That means that we can reserve a part of the physically hotadded memory to back vmemmap page tables. This implementation uses the beginning of the hotplugged memory for that purpose. There are some non-obviously things to consider though. Vmemmap pages are allocated/freed during the memory hotplug events (add_memory_resource(), try_remove_memory()) when the memory is added/removed. This means that the reserved physical range is not online although it is used. The most obvious side effect is that pfn_to_online_page() returns NULL for those pfns. The current design expects that this should be OK as the hotplugged memory is considered a garbage until it is onlined. For example hibernation wouldn't save the content of those vmmemmaps into the image so it wouldn't be restored on resume but this should be OK as there no real content to recover anyway while metadata is reachable from other data structures (e.g. vmemmap page tables). The reserved space is therefore (de)initialized during the {on,off}line events (mhp_{de}init_memmap_on_memory). That is done by extracting page allocator independent initialization from the regular onlining path. The primary reason to handle the reserved space outside of {on,off}line_pages is to make each initialization specific to the purpose rather than special case them in a single function. As per above, the functions that are introduced are: - mhp_init_memmap_on_memory: Initializes vmemmap pages by calling move_pfn_range_to_zone(), calls kasan_add_zero_shadow(), and onlines as many sections as vmemmap pages fully span. - mhp_deinit_memmap_on_memory: Offlines as many sections as vmemmap pages fully span, removes the range from zhe zone by remove_pfn_range_from_zone(), and calls kasan_remove_zero_shadow() for the range. The new function memory_block_online() calls mhp_init_memmap_on_memory() before doing the actual online_pages(). Should online_pages() fail, we clean up by calling mhp_deinit_memmap_on_memory(). Adjusting of present_pages is done at the end once we know that online_pages() succedeed. On offline, memory_block_offline() needs to unaccount vmemmap pages from present_pages() before calling offline_pages(). This is necessary because offline_pages() tears down some structures based on the fact whether the node or the zone become empty. If offline_pages() fails, we account back vmemmap pages. If it succeeds, we call mhp_deinit_memmap_on_memory(). Hot-remove: We need to be careful when removing memory, as adding and removing memory needs to be done with the same granularity. To check that this assumption is not violated, we check the memory range we want to remove and if a) any memory block has vmemmap pages and b) the range spans more than a single memory block, we scream out loud and refuse to proceed. If all is good and the range was using memmap on memory (aka vmemmap pages), we construct an altmap structure so free_hugepage_table does the right thing and calls vmem_altmap_free instead of free_pagetable. Link: https://lkml.kernel.org/r/20210421102701.25051-5-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
d1e153fe |
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04-May-2021 |
Pavel Tatashin <pasha.tatashin@soleen.com> |
mm/gup: migrate pinned pages out of movable zone We should not pin pages in ZONE_MOVABLE. Currently, we do not pin only movable CMA pages. Generalize the function that migrates CMA pages to migrate all movable pages. Use is_pinnable_page() to check which pages need to be migrated Link: https://lkml.kernel.org/r/20210215161349.246722-10-pasha.tatashin@soleen.com Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: James Morris <jmorris@namei.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sasha Levin <sashal@kernel.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Tyler Hicks <tyhicks@linux.microsoft.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
9afaf30f |
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04-May-2021 |
Pavel Tatashin <pasha.tatashin@soleen.com> |
mm/gup: do not migrate zero page On some platforms ZERO_PAGE(0) might end-up in a movable zone. Do not migrate zero page in gup during longterm pinning as migration of zero page is not allowed. For example, in x86 QEMU with 16G of memory and kernelcore=5G parameter, I see the following: Boot#1: zero_pfn 0x48a8d zero_pfn zone: ZONE_DMA32 Boot#2: zero_pfn 0x20168d zero_pfn zone: ZONE_MOVABLE On x86, empty_zero_page is declared in .bss and depending on the loader may end up in different physical locations during boots. Also, move is_zero_pfn() my_zero_pfn() functions under CONFIG_MMU, because zero_pfn that they are using is declared in memory.c which is compiled with CONFIG_MMU. Link: https://lkml.kernel.org/r/20210215161349.246722-9-pasha.tatashin@soleen.com Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: James Morris <jmorris@namei.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sasha Levin <sashal@kernel.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Tyler Hicks <tyhicks@linux.microsoft.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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198fba41 |
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30-Apr-2021 |
Mike Rapoport <rppt@kernel.org> |
mm/mmzone.h: fix existing kernel-doc comments and link them to core-api There are a couple of kernel-doc comments in include/linux/mmzone.h but they have minor formatting issues that would cause kernel-doc warnings. Fix the formatting of those comments, add missing Return: descriptions and link include/linux/mmzone.h to Documentation/core-api/mm-api.rst Link: https://lkml.kernel.org/r/20210426141927.1314326-2-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1f90a347 |
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25-Feb-2021 |
Dan Williams <dan.j.williams@intel.com> |
mm: teach pfn_to_online_page() about ZONE_DEVICE section collisions While pfn_to_online_page() is able to determine pfn_valid() at subsection granularity it is not able to reliably determine if a given pfn is also online if the section is mixes ZONE_{NORMAL,MOVABLE} with ZONE_DEVICE. This means that pfn_to_online_page() may return invalid @page objects. For example with a memory map like: 100000000-1fbffffff : System RAM 142000000-143002e16 : Kernel code 143200000-143713fff : Kernel rodata 143800000-143b15b7f : Kernel data 144227000-144ffffff : Kernel bss 1fc000000-2fbffffff : Persistent Memory (legacy) 1fc000000-2fbffffff : namespace0.0 This command: echo 0x1fc000000 > /sys/devices/system/memory/soft_offline_page ...succeeds when it should fail. When it succeeds it touches an uninitialized page and may crash or cause other damage (see dissolve_free_huge_page()). While the memory map above is contrived via the memmap=ss!nn kernel command line option, the collision happens in practice on shipping platforms. The memory controller resources that decode spans of physical address space are a limited resource. One technique platform-firmware uses to conserve those resources is to share a decoder across 2 devices to keep the address range contiguous. Unfortunately the unit of operation of a decoder is 64MiB while the Linux section size is 128MiB. This results in situations where, without subsection hotplug memory mappings with different lifetimes collide into one object that can only express one lifetime. Update move_pfn_range_to_zone() to flag (SECTION_TAINT_ZONE_DEVICE) a section that mixes ZONE_DEVICE pfns with other online pfns. With SECTION_TAINT_ZONE_DEVICE to delineate, pfn_to_online_page() can fall back to a slow-path check for ZONE_DEVICE pfns in an online section. In the fast path online_section() for a full ZONE_DEVICE section returns false. Because the collision case is rare, and for simplicity, the SECTION_TAINT_ZONE_DEVICE flag is never cleared once set. [dan.j.williams@intel.com: fix CONFIG_ZONE_DEVICE=n build] Link: https://lkml.kernel.org/r/CAPcyv4iX+7LAgAeSqx7Zw-Zd=ZV9gBv8Bo7oTbwCOOqJoZ3+Yg@mail.gmail.com Link: https://lkml.kernel.org/r/161058500675.1840162.7887862152161279354.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug") Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reported-by: Michal Hocko <mhocko@suse.com> Acked-by: Michal Hocko <mhocko@suse.com> Reported-by: David Hildenbrand <david@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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3c381db1 |
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25-Feb-2021 |
David Hildenbrand <david@redhat.com> |
mm/page_alloc: count CMA pages per zone and print them in /proc/zoneinfo Let's count the number of CMA pages per zone and print them in /proc/zoneinfo. Having access to the total number of CMA pages per zone is helpful for debugging purposes to know where exactly the CMA pages ended up, and to figure out how many pages of a zone might behave differently, even after some of these pages might already have been allocated. As one example, CMA pages part of a kernel zone cannot be used for ordinary kernel allocations but instead behave more like ZONE_MOVABLE. For now, we are only able to get the global nr+free cma pages from /proc/meminfo and the free cma pages per zone from /proc/zoneinfo. Example after this patch when booting a 6 GiB QEMU VM with "hugetlb_cma=2G": # cat /proc/zoneinfo | grep cma cma 0 nr_free_cma 0 cma 0 nr_free_cma 0 cma 524288 nr_free_cma 493016 cma 0 cma 0 # cat /proc/meminfo | grep Cma CmaTotal: 2097152 kB CmaFree: 1972064 kB Note: We print even without CONFIG_CMA, just like "nr_free_cma"; this way, one can be sure when spotting "cma 0", that there are definetly no CMA pages located in a zone. [david@redhat.com: v2] Link: https://lkml.kernel.org/r/20210128164533.18566-1-david@redhat.com [david@redhat.com: v3] Link: https://lkml.kernel.org/r/20210129113451.22085-1-david@redhat.com Link: https://lkml.kernel.org/r/20210127101813.6370-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: David Rientjes <rientjes@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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2091339d |
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24-Feb-2021 |
Yu Zhao <yuzhao@google.com> |
mm/vmscan.c: make lruvec_lru_size() static All other references to the function were removed after commit b910718a948a ("mm: vmscan: detect file thrashing at the reclaim root"). Link: https://lore.kernel.org/linux-mm/20201207220949.830352-11-yuzhao@google.com/ Link: https://lkml.kernel.org/r/20210122220600.906146-11-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b6038942 |
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24-Feb-2021 |
Shakeel Butt <shakeelb@google.com> |
mm: memcg: add swapcache stat for memcg v2 This patch adds swapcache stat for the cgroup v2. The swapcache represents the memory that is accounted against both the memory and the swap limit of the cgroup. The main motivation behind exposing the swapcache stat is for enabling users to gracefully migrate from cgroup v1's memsw counter to cgroup v2's memory and swap counters. Cgroup v1's memsw limit allows users to limit the memory+swap usage of a workload but without control on the exact proportion of memory and swap. Cgroup v2 provides separate limits for memory and swap which enables more control on the exact usage of memory and swap individually for the workload. With some little subtleties, the v1's memsw limit can be switched with the sum of the v2's memory and swap limits. However the alternative for memsw usage is not yet available in cgroup v2. Exposing per-cgroup swapcache stat enables that alternative. Adding the memory usage and swap usage and subtracting the swapcache will approximate the memsw usage. This will help in the transparent migration of the workloads depending on memsw usage and limit to v2' memory and swap counters. The reasons these applications are still interested in this approximate memsw usage are: (1) these applications are not really interested in two separate memory and swap usage metrics. A single usage metric is more simple to use and reason about for them. (2) The memsw usage metric hides the underlying system's swap setup from the applications. Applications with multiple instances running in a datacenter with heterogeneous systems (some have swap and some don't) will keep seeing a consistent view of their usage. [akpm@linux-foundation.org: fix CONFIG_SWAP=n build] Link: https://lkml.kernel.org/r/20210108155813.2914586-3-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Roman Gushchin <guro@fb.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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380780e7 |
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24-Feb-2021 |
Muchun Song <songmuchun@bytedance.com> |
mm: memcontrol: convert NR_FILE_PMDMAPPED account to pages Currently we use struct per_cpu_nodestat to cache the vmstat counters, which leads to inaccurate statistics especially THP vmstat counters. In the systems with hundreds of processors it can be GBs of memory. For example, for a 96 CPUs system, the threshold is the maximum number of 125. And the per cpu counters can cache 23.4375 GB in total. The THP page is already a form of batched addition (it will add 512 worth of memory in one go) so skipping the batching seems like sensible. Although every THP stats update overflows the per-cpu counter, resorting to atomic global updates. But it can make the statistics more accuracy for the THP vmstat counters. So we convert the NR_FILE_PMDMAPPED account to pages. This patch is consistent with 8f182270dfec ("mm/swap.c: flush lru pvecs on compound page arrival"). Doing this also can make the unit of vmstat counters more unified. Finally, the unit of the vmstat counters are pages, kB and bytes. The B/KB suffix can tell us that the unit is bytes or kB. The rest which is without suffix are pages. Link: https://lkml.kernel.org/r/20201228164110.2838-7-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@suse.com> Cc: NeilBrown <neilb@suse.de> Cc: Pankaj Gupta <pankaj.gupta@cloud.ionos.com> Cc: Rafael. J. Wysocki <rafael@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Roman Gushchin <guro@fb.com> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a1528e21 |
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24-Feb-2021 |
Muchun Song <songmuchun@bytedance.com> |
mm: memcontrol: convert NR_SHMEM_PMDMAPPED account to pages Currently we use struct per_cpu_nodestat to cache the vmstat counters, which leads to inaccurate statistics especially THP vmstat counters. In the systems with hundreds of processors it can be GBs of memory. For example, for a 96 CPUs system, the threshold is the maximum number of 125. And the per cpu counters can cache 23.4375 GB in total. The THP page is already a form of batched addition (it will add 512 worth of memory in one go) so skipping the batching seems like sensible. Although every THP stats update overflows the per-cpu counter, resorting to atomic global updates. But it can make the statistics more accuracy for the THP vmstat counters. So we convert the NR_SHMEM_PMDMAPPED account to pages. This patch is consistent with 8f182270dfec ("mm/swap.c: flush lru pvecs on compound page arrival"). Doing this also can make the unit of vmstat counters more unified. Finally, the unit of the vmstat counters are pages, kB and bytes. The B/KB suffix can tell us that the unit is bytes or kB. The rest which is without suffix are pages. Link: https://lkml.kernel.org/r/20201228164110.2838-6-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@suse.com> Cc: NeilBrown <neilb@suse.de> Cc: Pankaj Gupta <pankaj.gupta@cloud.ionos.com> Cc: Rafael. J. Wysocki <rafael@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Roman Gushchin <guro@fb.com> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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57b2847d |
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24-Feb-2021 |
Muchun Song <songmuchun@bytedance.com> |
mm: memcontrol: convert NR_SHMEM_THPS account to pages Currently we use struct per_cpu_nodestat to cache the vmstat counters, which leads to inaccurate statistics especially THP vmstat counters. In the systems with hundreds of processors it can be GBs of memory. For example, for a 96 CPUs system, the threshold is the maximum number of 125. And the per cpu counters can cache 23.4375 GB in total. The THP page is already a form of batched addition (it will add 512 worth of memory in one go) so skipping the batching seems like sensible. Although every THP stats update overflows the per-cpu counter, resorting to atomic global updates. But it can make the statistics more accuracy for the THP vmstat counters. So we convert the NR_SHMEM_THPS account to pages. This patch is consistent with 8f182270dfec ("mm/swap.c: flush lru pvecs on compound page arrival"). Doing this also can make the unit of vmstat counters more unified. Finally, the unit of the vmstat counters are pages, kB and bytes. The B/KB suffix can tell us that the unit is bytes or kB. The rest which is without suffix are pages. Link: https://lkml.kernel.org/r/20201228164110.2838-5-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@suse.com> Cc: NeilBrown <neilb@suse.de> Cc: Pankaj Gupta <pankaj.gupta@cloud.ionos.com> Cc: Rafael. J. Wysocki <rafael@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Roman Gushchin <guro@fb.com> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bf9ecead |
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24-Feb-2021 |
Muchun Song <songmuchun@bytedance.com> |
mm: memcontrol: convert NR_FILE_THPS account to pages Currently we use struct per_cpu_nodestat to cache the vmstat counters, which leads to inaccurate statistics especially THP vmstat counters. In the systems with if hundreds of processors it can be GBs of memory. For example, for a 96 CPUs system, the threshold is the maximum number of 125. And the per cpu counters can cache 23.4375 GB in total. The THP page is already a form of batched addition (it will add 512 worth of memory in one go) so skipping the batching seems like sensible. Although every THP stats update overflows the per-cpu counter, resorting to atomic global updates. But it can make the statistics more accuracy for the THP vmstat counters. So we convert the NR_FILE_THPS account to pages. This patch is consistent with 8f182270dfec ("mm/swap.c: flush lru pvecs on compound page arrival"). Doing this also can make the unit of vmstat counters more unified. Finally, the unit of the vmstat counters are pages, kB and bytes. The B/KB suffix can tell us that the unit is bytes or kB. The rest which is without suffix are pages. Link: https://lkml.kernel.org/r/20201228164110.2838-4-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@suse.com> Cc: NeilBrown <neilb@suse.de> Cc: Pankaj Gupta <pankaj.gupta@cloud.ionos.com> Cc: Rafael. J. Wysocki <rafael@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Roman Gushchin <guro@fb.com> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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69473e5d |
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24-Feb-2021 |
Muchun Song <songmuchun@bytedance.com> |
mm: memcontrol: convert NR_ANON_THPS account to pages Currently we use struct per_cpu_nodestat to cache the vmstat counters, which leads to inaccurate statistics especially THP vmstat counters. In the systems with hundreds of processors it can be GBs of memory. For example, for a 96 CPUs system, the threshold is the maximum number of 125. And the per cpu counters can cache 23.4375 GB in total. The THP page is already a form of batched addition (it will add 512 worth of memory in one go) so skipping the batching seems like sensible. Although every THP stats update overflows the per-cpu counter, resorting to atomic global updates. But it can make the statistics more accuracy for the THP vmstat counters. So we convert the NR_ANON_THPS account to pages. This patch is consistent with 8f182270dfec ("mm/swap.c: flush lru pvecs on compound page arrival"). Doing this also can make the unit of vmstat counters more unified. Finally, the unit of the vmstat counters are pages, kB and bytes. The B/KB suffix can tell us that the unit is bytes or kB. The rest which is without suffix are pages. Link: https://lkml.kernel.org/r/20201228164110.2838-3-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Rafael. J. Wysocki <rafael@kernel.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Roman Gushchin <guro@fb.com> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Feng Tang <feng.tang@intel.com> Cc: NeilBrown <neilb@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Pankaj Gupta <pankaj.gupta@cloud.ionos.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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15b44736 |
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15-Dec-2020 |
Hugh Dickins <hughd@google.com> |
mm/lru: revise the comments of lru_lock Since we changed the pgdat->lru_lock to lruvec->lru_lock, it's time to fix the incorrect comments in code. Also fixed some zone->lru_lock comment error from ancient time. etc. I struggled to understand the comment above move_pages_to_lru() (surely it never calls page_referenced()), and eventually realized that most of it had got separated from shrink_active_list(): move that comment back. Link: https://lkml.kernel.org/r/1604566549-62481-20-git-send-email-alex.shi@linux.alibaba.com Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Jann Horn <jannh@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Matthew Wilcox <willy@infradead.org> Cc: Alexander Duyck <alexander.duyck@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Chen, Rong A" <rong.a.chen@intel.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mika Penttilä <mika.penttila@nextfour.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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6168d0da |
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15-Dec-2020 |
Alex Shi <alex.shi@linux.alibaba.com> |
mm/lru: replace pgdat lru_lock with lruvec lock This patch moves per node lru_lock into lruvec, thus bring a lru_lock for each of memcg per node. So on a large machine, each of memcg don't have to suffer from per node pgdat->lru_lock competition. They could go fast with their self lru_lock. After move memcg charge before lru inserting, page isolation could serialize page's memcg, then per memcg lruvec lock is stable and could replace per node lru lock. In isolate_migratepages_block(), compact_unlock_should_abort and lock_page_lruvec_irqsave are open coded to work with compact_control. Also add a debug func in locking which may give some clues if there are sth out of hands. Daniel Jordan's testing show 62% improvement on modified readtwice case on his 2P * 10 core * 2 HT broadwell box. https://lore.kernel.org/lkml/20200915165807.kpp7uhiw7l3loofu@ca-dmjordan1.us.oracle.com/ Hugh Dickins helped on the patch polish, thanks! [alex.shi@linux.alibaba.com: fix comment typo] Link: https://lkml.kernel.org/r/5b085715-292a-4b43-50b3-d73dc90d1de5@linux.alibaba.com [alex.shi@linux.alibaba.com: use page_memcg()] Link: https://lkml.kernel.org/r/5a4c2b72-7ee8-2478-fc0e-85eb83aafec4@linux.alibaba.com Link: https://lkml.kernel.org/r/1604566549-62481-18-git-send-email-alex.shi@linux.alibaba.com Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Rong Chen <rong.a.chen@intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Alexander Duyck <alexander.duyck@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Jann Horn <jannh@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Mika Penttilä <mika.penttila@nextfour.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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952eaf81 |
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14-Dec-2020 |
Vlastimil Babka <vbabka@suse.cz> |
mm, page_alloc: cache pageset high and batch in struct zone All per-cpu pagesets for a zone use the same high and batch values, that are duplicated there just for performance (locality) reasons. This patch adds the same variables also to struct zone as a shared copy. This will be useful later for making possible to disable pcplists temporarily by setting high value to 0, while remembering the values for restoring them later. But we can also immediately benefit from not updating pagesets of all possible cpus in case the newly recalculated values (after sysctl change or memory online/offline) are actually unchanged from the previous ones. Link: https://lkml.kernel.org/r/20201111092812.11329-6-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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5e545df3 |
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14-Dec-2020 |
Mike Rapoport <rppt@kernel.org> |
arm: remove CONFIG_ARCH_HAS_HOLES_MEMORYMODEL ARM is the only architecture that defines CONFIG_ARCH_HAS_HOLES_MEMORYMODEL which in turn enables memmap_valid_within() function that is intended to verify existence of struct page associated with a pfn when there are holes in the memory map. However, the ARCH_HAS_HOLES_MEMORYMODEL also enables HAVE_ARCH_PFN_VALID and arch-specific pfn_valid() implementation that also deals with the holes in the memory map. The only two users of memmap_valid_within() call this function after a call to pfn_valid() so the memmap_valid_within() check becomes redundant. Remove CONFIG_ARCH_HAS_HOLES_MEMORYMODEL and memmap_valid_within() and rely entirely on ARM's implementation of pfn_valid() that is now enabled unconditionally. Link: https://lkml.kernel.org/r/20201101170454.9567-9-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matt Turner <mattst88@gmail.com> Cc: Meelis Roos <mroos@linux.ee> Cc: Michael Schmitz <schmitzmic@gmail.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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03e92a5e |
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14-Dec-2020 |
Mike Rapoport <rppt@kernel.org> |
ia64: remove custom __early_pfn_to_nid() The ia64 implementation of __early_pfn_to_nid() essentially relies on the same data as the generic implementation. The correspondence between memory ranges and nodes is set in memblock during early memory initialization in register_active_ranges() function. The initialization of sparsemem that requires early_pfn_to_nid() happens later and it can use the memblock information like the other architectures. Link: https://lkml.kernel.org/r/20201101170454.9567-3-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matt Turner <mattst88@gmail.com> Cc: Meelis Roos <mroos@linux.ee> Cc: Michael Schmitz <schmitzmic@gmail.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f0c0c115 |
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14-Dec-2020 |
Shakeel Butt <shakeelb@google.com> |
mm: memcontrol: account pagetables per node For many workloads, pagetable consumption is significant and it makes sense to expose it in the memory.stat for the memory cgroups. However at the moment, the pagetables are accounted per-zone. Converting them to per-node and using the right interface will correctly account for the memory cgroups as well. [akpm@linux-foundation.org: export __mod_lruvec_page_state to modules for arch/mips/kvm/] Link: https://lkml.kernel.org/r/20201130212541.2781790-3-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Roman Gushchin <guro@fb.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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04435217 |
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19-Nov-2020 |
Nicolas Saenz Julienne <nsaenzjulienne@suse.de> |
mm: Remove examples from enum zone_type comment We can't really list every setup in common code. On top of that they are unlikely to stay true for long as things change in the arch trees independently of this comment. Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20201119175400.9995-8-nsaenzjulienne@suse.de Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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1f0f8c0d |
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15-Oct-2020 |
Mike Rapoport <rppt@kernel.org> |
include/linux/mmzone.h: remove unused early_pfn_valid() The early_pfn_valid() macro is defined but it is never used. Remove it. Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Hildenbrand <david@redhat.com> Link: https://lkml.kernel.org/r/20200923162915.26935-1-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ed017373 |
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15-Oct-2020 |
Yu Zhao <yuzhao@google.com> |
mm: use self-explanatory macros rather than "2" Signed-off-by: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Alex Shi <alex.shi@linux.alibaba.com> Link: http://lkml.kernel.org/r/20200831175042.3527153-2-yuzhao@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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30d8ec73 |
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13-Oct-2020 |
Mateusz Nosek <mateusznosek0@gmail.com> |
mmzone: clean code by removing unused macro parameter Previously 'for_next_zone_zonelist_nodemask' macro parameter 'zlist' was unused so this patch removes it. Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/20200917211906.30059-1-mateusznosek0@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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9181a980 |
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13-Oct-2020 |
David Hildenbrand <david@redhat.com> |
mm: document semantics of ZONE_MOVABLE Let's document what ZONE_MOVABLE means, how it's used, and which special cases we have regarding unmovable pages (memory offlining vs. migration / allocations). Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Baoquan He <bhe@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Qian Cai <cai@lca.pw> Link: http://lkml.kernel.org/r/20200816125333.7434-7-david@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c1d0da83 |
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25-Sep-2020 |
Laurent Dufour <ldufour@linux.ibm.com> |
mm: replace memmap_context by meminit_context Patch series "mm: fix memory to node bad links in sysfs", v3. Sometimes, firmware may expose interleaved memory layout like this: Early memory node ranges node 1: [mem 0x0000000000000000-0x000000011fffffff] node 2: [mem 0x0000000120000000-0x000000014fffffff] node 1: [mem 0x0000000150000000-0x00000001ffffffff] node 0: [mem 0x0000000200000000-0x000000048fffffff] node 2: [mem 0x0000000490000000-0x00000007ffffffff] In that case, we can see memory blocks assigned to multiple nodes in sysfs: $ ls -l /sys/devices/system/memory/memory21 total 0 lrwxrwxrwx 1 root root 0 Aug 24 05:27 node1 -> ../../node/node1 lrwxrwxrwx 1 root root 0 Aug 24 05:27 node2 -> ../../node/node2 -rw-r--r-- 1 root root 65536 Aug 24 05:27 online -r--r--r-- 1 root root 65536 Aug 24 05:27 phys_device -r--r--r-- 1 root root 65536 Aug 24 05:27 phys_index drwxr-xr-x 2 root root 0 Aug 24 05:27 power -r--r--r-- 1 root root 65536 Aug 24 05:27 removable -rw-r--r-- 1 root root 65536 Aug 24 05:27 state lrwxrwxrwx 1 root root 0 Aug 24 05:25 subsystem -> ../../../../bus/memory -rw-r--r-- 1 root root 65536 Aug 24 05:25 uevent -r--r--r-- 1 root root 65536 Aug 24 05:27 valid_zones The same applies in the node's directory with a memory21 link in both the node1 and node2's directory. This is wrong but doesn't prevent the system to run. However when later, one of these memory blocks is hot-unplugged and then hot-plugged, the system is detecting an inconsistency in the sysfs layout and a BUG_ON() is raised: kernel BUG at /Users/laurent/src/linux-ppc/mm/memory_hotplug.c:1084! LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: rpadlpar_io rpaphp pseries_rng rng_core vmx_crypto gf128mul binfmt_misc ip_tables x_tables xfs libcrc32c crc32c_vpmsum autofs4 CPU: 8 PID: 10256 Comm: drmgr Not tainted 5.9.0-rc1+ #25 Call Trace: add_memory_resource+0x23c/0x340 (unreliable) __add_memory+0x5c/0xf0 dlpar_add_lmb+0x1b4/0x500 dlpar_memory+0x1f8/0xb80 handle_dlpar_errorlog+0xc0/0x190 dlpar_store+0x198/0x4a0 kobj_attr_store+0x30/0x50 sysfs_kf_write+0x64/0x90 kernfs_fop_write+0x1b0/0x290 vfs_write+0xe8/0x290 ksys_write+0xdc/0x130 system_call_exception+0x160/0x270 system_call_common+0xf0/0x27c This has been seen on PowerPC LPAR. The root cause of this issue is that when node's memory is registered, the range used can overlap another node's range, thus the memory block is registered to multiple nodes in sysfs. There are two issues here: (a) The sysfs memory and node's layouts are broken due to these multiple links (b) The link errors in link_mem_sections() should not lead to a system panic. To address (a) register_mem_sect_under_node should not rely on the system state to detect whether the link operation is triggered by a hot plug operation or not. This is addressed by the patches 1 and 2 of this series. Issue (b) will be addressed separately. This patch (of 2): The memmap_context enum is used to detect whether a memory operation is due to a hot-add operation or happening at boot time. Make it general to the hotplug operation and rename it as meminit_context. There is no functional change introduced by this patch Suggested-by: David Hildenbrand <david@redhat.com> Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J . Wysocki" <rafael@kernel.org> Cc: Nathan Lynch <nathanl@linux.ibm.com> Cc: Scott Cheloha <cheloha@linux.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20200915094143.79181-1-ldufour@linux.ibm.com Link: https://lkml.kernel.org/r/20200915132624.9723-1-ldufour@linux.ibm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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860b3272 |
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11-Aug-2020 |
Alex Shi <alex.shi@linux.alibaba.com> |
mm/compaction: correct the comments of compact_defer_shift There is no compact_defer_limit. It should be compact_defer_shift in use. and add compact_order_failed explanation. Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Link: http://lkml.kernel.org/r/3bd60e1b-a74e-050d-ade4-6e8f54e00b92@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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170b04b7 |
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11-Aug-2020 |
Joonsoo Kim <iamjoonsoo.kim@lge.com> |
mm/workingset: prepare the workingset detection infrastructure for anon LRU To prepare the workingset detection for anon LRU, this patch splits workingset event counters for refault, activate and restore into anon and file variants, as well as the refaults counter in struct lruvec. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Link: http://lkml.kernel.org/r/1595490560-15117-4-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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535b81e2 |
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07-Aug-2020 |
Wei Yang <richard.weiyang@linux.alibaba.com> |
mm/page_alloc.c: remove unnecessary end_bitidx for [set|get]_pfnblock_flags_mask() After previous cleanup, the end_bitidx is not necessary any more. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Link: http://lkml.kernel.org/r/20200623124201.8199-4-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d38ac97f |
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07-Aug-2020 |
Wei Yang <richard.weiyang@linux.alibaba.com> |
mm/page_alloc.c: replace the definition of NR_MIGRATETYPE_BITS with PB_migratetype_bits We already have the definition of PB_migratetype_bits and current NR_MIGRATETYPE_BITS looks like a cyclic definition. Just use PB_migratetype_bits is enough. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Link: http://lkml.kernel.org/r/20200623124201.8199-1-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c89ab04f |
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07-Aug-2020 |
Mike Rapoport <rppt@kernel.org> |
mm/sparse: cleanup the code surrounding memory_present() After removal of CONFIG_HAVE_MEMBLOCK_NODE_MAP we have two equivalent functions that call memory_present() for each region in memblock.memory: sparse_memory_present_with_active_regions() and membocks_present(). Moreover, all architectures have a call to either of these functions preceding the call to sparse_init() and in the most cases they are called one after the other. Mark the regions from memblock.memory as present during sparce_init() by making sparse_init() call memblocks_present(), make memblocks_present() and memory_present() functions static and remove redundant sparse_memory_present_with_active_regions() function. Also remove no longer required HAVE_MEMORY_PRESENT configuration option. Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200712083130.22919-1-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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991e7673 |
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07-Aug-2020 |
Shakeel Butt <shakeelb@google.com> |
mm: memcontrol: account kernel stack per node Currently the kernel stack is being accounted per-zone. There is no need to do that. In addition due to being per-zone, memcg has to keep a separate MEMCG_KERNEL_STACK_KB. Make the stat per-node and deprecate MEMCG_KERNEL_STACK_KB as memcg_stat_item is an extension of node_stat_item. In addition localize the kernel stack stats updates to account_kernel_stack(). Signed-off-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Roman Gushchin <guro@fb.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Link: http://lkml.kernel.org/r/20200630161539.1759185-1-shakeelb@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
d42f3245 |
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07-Aug-2020 |
Roman Gushchin <guro@fb.com> |
mm: memcg: convert vmstat slab counters to bytes In order to prepare for per-object slab memory accounting, convert NR_SLAB_RECLAIMABLE and NR_SLAB_UNRECLAIMABLE vmstat items to bytes. To make it obvious, rename them to NR_SLAB_RECLAIMABLE_B and NR_SLAB_UNRECLAIMABLE_B (similar to NR_KERNEL_STACK_KB). Internally global and per-node counters are stored in pages, however memcg and lruvec counters are stored in bytes. This scheme may look weird, but only for now. As soon as slab pages will be shared between multiple cgroups, global and node counters will reflect the total number of slab pages. However memcg and lruvec counters will be used for per-memcg slab memory tracking, which will take separate kernel objects in the account. Keeping global and node counters in pages helps to avoid additional overhead. The size of slab memory shouldn't exceed 4Gb on 32-bit machines, so it will fit into atomic_long_t we use for vmstats. Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/20200623174037.3951353-4-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
ea426c2a |
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07-Aug-2020 |
Roman Gushchin <guro@fb.com> |
mm: memcg: prepare for byte-sized vmstat items To implement per-object slab memory accounting, we need to convert slab vmstat counters to bytes. Actually, out of 4 levels of counters: global, per-node, per-memcg and per-lruvec only two last levels will require byte-sized counters. It's because global and per-node counters will be counting the number of slab pages, and per-memcg and per-lruvec will be counting the amount of memory taken by charged slab objects. Converting all vmstat counters to bytes or even all slab counters to bytes would introduce an additional overhead. So instead let's store global and per-node counters in pages, and memcg and lruvec counters in bytes. To make the API clean all access helpers (both on the read and write sides) are dealing with bytes. To avoid back-and-forth conversions a new flavor of read-side helpers is introduced, which always returns values in pages: node_page_state_pages() and global_node_page_state_pages(). Actually new helpers are just reading raw values. Old helpers are simple wrappers, which will complain on an attempt to read byte value, because at the moment no one actually needs bytes. Thanks to Johannes Weiner for the idea of having the byte-sized API on top of the page-sized internal storage. Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/20200623174037.3951353-3-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
31d8fcac |
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25-Jun-2020 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: workingset: age nonresident information alongside anonymous pages Patch series "fix for "mm: balance LRU lists based on relative thrashing" patchset" This patchset fixes some problems of the patchset, "mm: balance LRU lists based on relative thrashing", which is now merged on the mainline. Patch "mm: workingset: let cache workingset challenge anon fix" is the result of discussion with Johannes. See following link. http://lkml.kernel.org/r/20200520232525.798933-6-hannes@cmpxchg.org And, the other two are minor things which are found when I try to rebase my patchset. This patch (of 3): After ("mm: workingset: let cache workingset challenge anon fix"), we compare refault distances to active_file + anon. But age of the non-resident information is only driven by the file LRU. As a result, we may overestimate the recency of any incoming refaults and activate them too eagerly, causing unnecessary LRU churn in certain situations. Make anon aging drive nonresident age as well to address that. Link: http://lkml.kernel.org/r/1592288204-27734-1-git-send-email-iamjoonsoo.kim@lge.com Link: http://lkml.kernel.org/r/1592288204-27734-2-git-send-email-iamjoonsoo.kim@lge.com Fixes: 34e58cac6d8f2a ("mm: workingset: let cache workingset challenge anon") Reported-by: Joonsoo Kim <js1304@gmail.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Rik van Riel <riel@surriel.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
496df3d3 |
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10-Jun-2020 |
Ben Widawsky <ben.widawsky@intel.com> |
mm: add comments on pglist_data zones While making other modifications it was easy to confuse the two struct members node_zones and node_zonelists. For those already familiar with the code, this might seem to be a silly patch, but it's quite helpful to disambiguate the similar-sounding fields While here, add a small comment on why nr_zones isn't simply MAX_NR_ZONES Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200520205443.2757414-1-ben.widawsky@intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
1431d4d1 |
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03-Jun-2020 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: base LRU balancing on an explicit cost model Currently, scan pressure between the anon and file LRU lists is balanced based on a mixture of reclaim efficiency and a somewhat vague notion of "value" of having certain pages in memory over others. That concept of value is problematic, because it has caused us to count any event that remotely makes one LRU list more or less preferrable for reclaim, even when these events are not directly comparable and impose very different costs on the system. One example is referenced file pages that we still deactivate and referenced anonymous pages that we actually rotate back to the head of the list. There is also conceptual overlap with the LRU algorithm itself. By rotating recently used pages instead of reclaiming them, the algorithm already biases the applied scan pressure based on page value. Thus, when rebalancing scan pressure due to rotations, we should think of reclaim cost, and leave assessing the page value to the LRU algorithm. Lastly, considering both value-increasing as well as value-decreasing events can sometimes cause the same type of event to be counted twice, i.e. how rotating a page increases the LRU value, while reclaiming it succesfully decreases the value. In itself this will balance out fine, but it quietly skews the impact of events that are only recorded once. The abstract metric of "value", the murky relationship with the LRU algorithm, and accounting both negative and positive events make the current pressure balancing model hard to reason about and modify. This patch switches to a balancing model of accounting the concrete, actually observed cost of reclaiming one LRU over another. For now, that cost includes pages that are scanned but rotated back to the list head. Subsequent patches will add consideration for IO caused by refaulting of recently evicted pages. Replace struct zone_reclaim_stat with two cost counters in the lruvec, and make everything that affects cost go through a new lru_note_cost() function. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Link: http://lkml.kernel.org/r/20200520232525.798933-9-hannes@cmpxchg.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
3d060856 |
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03-Jun-2020 |
Pavel Tatashin <pasha.tatashin@soleen.com> |
mm: initialize deferred pages with interrupts enabled Initializing struct pages is a long task and keeping interrupts disabled for the duration of this operation introduces a number of problems. 1. jiffies are not updated for long period of time, and thus incorrect time is reported. See proposed solution and discussion here: lkml/20200311123848.118638-1-shile.zhang@linux.alibaba.com 2. It prevents farther improving deferred page initialization by allowing intra-node multi-threading. We are keeping interrupts disabled to solve a rather theoretical problem that was never observed in real world (See 3a2d7fa8a3d5). Let's keep interrupts enabled. In case we ever encounter a scenario where an interrupt thread wants to allocate large amount of memory this early in boot we can deal with that by growing zone (see deferred_grow_zone()) by the needed amount before starting deferred_init_memmap() threads. Before: [ 1.232459] node 0 initialised, 12058412 pages in 1ms After: [ 1.632580] node 0 initialised, 12051227 pages in 436ms Fixes: 3a2d7fa8a3d5 ("mm: disable interrupts while initializing deferred pages") Reported-by: Shile Zhang <shile.zhang@linux.alibaba.com> Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Williams <dan.j.williams@intel.com> Cc: James Morris <jmorris@namei.org> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Sasha Levin <sashal@kernel.org> Cc: Yiqian Wei <yiwei@redhat.com> Cc: <stable@vger.kernel.org> [4.17+] Link: http://lkml.kernel.org/r/20200403140952.17177-3-pasha.tatashin@soleen.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
97a225e6 |
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03-Jun-2020 |
Joonsoo Kim <iamjoonsoo.kim@lge.com> |
mm/page_alloc: integrate classzone_idx and high_zoneidx classzone_idx is just different name for high_zoneidx now. So, integrate them and add some comment to struct alloc_context in order to reduce future confusion about the meaning of this variable. The accessor, ac_classzone_idx() is also removed since it isn't needed after integration. In addition to integration, this patch also renames high_zoneidx to highest_zoneidx since it represents more precise meaning. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Baoquan He <bhe@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Ye Xiaolong <xiaolong.ye@intel.com> Link: http://lkml.kernel.org/r/1587095923-7515-3-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
3f08a302 |
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03-Jun-2020 |
Mike Rapoport <rppt@kernel.org> |
mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option CONFIG_HAVE_MEMBLOCK_NODE_MAP is used to differentiate initialization of nodes and zones structures between the systems that have region to node mapping in memblock and those that don't. Currently all the NUMA architectures enable this option and for the non-NUMA systems we can presume that all the memory belongs to node 0 and therefore the compile time configuration option is not required. The remaining few architectures that use DISCONTIGMEM without NUMA are easily updated to use memblock_add_node() instead of memblock_add() and thus have proper correspondence of memblock regions to NUMA nodes. Still, free_area_init_node() must have a backward compatible version because its semantics with and without CONFIG_HAVE_MEMBLOCK_NODE_MAP is different. Once all the architectures will use the new semantics, the entire compatibility layer can be dropped. To avoid addition of extra run time memory to store node id for architectures that keep memblock but have only a single node, the node id field of the memblock_region is guarded by CONFIG_NEED_MULTIPLE_NODES and the corresponding accessors presume that in those cases it is always 0. Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Hoan Tran <hoan@os.amperecomputing.com> [arm64] Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64] Cc: Baoquan He <bhe@redhat.com> Cc: Brian Cain <bcain@codeaurora.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200412194859.12663-4-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
6f24fbd3 |
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03-Jun-2020 |
Mike Rapoport <rppt@kernel.org> |
mm: make early_pfn_to_nid() and related defintions close to each other early_pfn_to_nid() and its helper __early_pfn_to_nid() are spread around include/linux/mm.h, include/linux/mmzone.h and mm/page_alloc.c. Drop unused stub for __early_pfn_to_nid() and move its actual generic implementation close to its users. Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Hoan Tran <hoan@os.amperecomputing.com> [arm64] Reviewed-by: Baoquan He <bhe@redhat.com> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200412194859.12663-3-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
8d92890b |
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01-Jun-2020 |
NeilBrown <neilb@suse.de> |
mm/writeback: discard NR_UNSTABLE_NFS, use NR_WRITEBACK instead After an NFS page has been written it is considered "unstable" until a COMMIT request succeeds. If the COMMIT fails, the page will be re-written. These "unstable" pages are currently accounted as "reclaimable", either in WB_RECLAIMABLE, or in NR_UNSTABLE_NFS which is included in a 'reclaimable' count. This might have made sense when sending the COMMIT required a separate action by the VFS/MM (e.g. releasepage() used to send a COMMIT). However now that all writes generated by ->writepages() will automatically be followed by a COMMIT (since commit 919e3bd9a875 ("NFS: Ensure we commit after writeback is complete")) it makes more sense to treat them as writeback pages. So this patch removes NR_UNSTABLE_NFS and accounts unstable pages in NR_WRITEBACK and WB_WRITEBACK. A particular effect of this change is that when wb_check_background_flush() calls wb_over_bg_threshold(), the latter will report 'true' a lot less often as the 'unstable' pages are no longer considered 'dirty' (as there is nothing that writeback can do about them anyway). Currently wb_check_background_flush() will trigger writeback to NFS even when there are relatively few dirty pages (if there are lots of unstable pages), this can result in small writes going to the server (10s of Kilobytes rather than a Megabyte) which hurts throughput. With this patch, there are fewer writes which are each larger on average. Where the NR_UNSTABLE_NFS count was included in statistics virtual-files, the entry is retained, but the value is hard-coded as zero. static trace points and warning printks which mentioned this counter no longer report it. [akpm@linux-foundation.org: re-layout comment] [akpm@linux-foundation.org: fix printk warning] Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Trond Myklebust <trond.myklebust@hammerspace.com> Acked-by: Michal Hocko <mhocko@suse.com> [mm] Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Link: http://lkml.kernel.org/r/87d06j7gqa.fsf@notabene.neil.brown.name Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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628d06a4 |
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27-Apr-2020 |
Sami Tolvanen <samitolvanen@google.com> |
scs: Add page accounting for shadow call stack allocations This change adds accounting for the memory allocated for shadow stacks. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Will Deacon <will@kernel.org>
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32927393 |
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24-Apr-2020 |
Christoph Hellwig <hch@lst.de> |
sysctl: pass kernel pointers to ->proc_handler Instead of having all the sysctl handlers deal with user pointers, which is rather hairy in terms of the BPF interaction, copy the input to and from userspace in common code. This also means that the strings are always NUL-terminated by the common code, making the API a little bit safer. As most handler just pass through the data to one of the common handlers a lot of the changes are mechnical. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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2374c09b |
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24-Apr-2020 |
Christoph Hellwig <hch@lst.de> |
sysctl: remove all extern declaration from sysctl.c Extern declarations in .c files are a bad style and can lead to mismatches. Use existing definitions in headers where they exist, and otherwise move the external declarations to suitable header files. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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26363af5 |
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24-Apr-2020 |
Christoph Hellwig <hch@lst.de> |
mm: remove watermark_boost_factor_sysctl_handler watermark_boost_factor_sysctl_handler is just a pointless wrapper for proc_dointvec_minmax, so remove it and use proc_dointvec_minmax directly. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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6218d740 |
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06-Apr-2020 |
Waiman Long <longman@redhat.com> |
mm: remove dummy struct bootmem_data/bootmem_data_t Both bootmem_data and bootmem_data_t structures are no longer defined. Remove the dummy forward declarations. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Baoquan He <bhe@redhat.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Link: http://lkml.kernel.org/r/20200326022617.26208-1-longman@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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0a9f9f62 |
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06-Apr-2020 |
Baoquan He <bhe@redhat.com> |
mm/sparse.c: only use subsection map in VMEMMAP case Currently, to support subsection aligned memory region adding for pmem, subsection map is added to track which subsection is present. However, config ZONE_DEVICE depends on SPARSEMEM_VMEMMAP. It means subsection map only makes sense when SPARSEMEM_VMEMMAP enabled. For the classic sparse, it's meaningless. Even worse, it may confuse people when checking code related to the classic sparse. About the classic sparse which doesn't support subsection hotplug, Dan said it's more because the effort and maintenance burden outweighs the benefit. Besides, the current 64 bit ARCHes all enable SPARSEMEM_VMEMMAP_ENABLE by default. Combining the above reasons, no need to provide subsection map and the relevant handling for the classic sparse. Let's remove them. Signed-off-by: Baoquan He <bhe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Link: http://lkml.kernel.org/r/20200312124414.439-4-bhe@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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6ab01363 |
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06-Apr-2020 |
Alexander Duyck <alexander.h.duyck@linux.intel.com> |
mm: use zone and order instead of free area in free_list manipulators In order to enable the use of the zone from the list manipulator functions I will need access to the zone pointer. As it turns out most of the accessors were always just being directly passed &zone->free_area[order] anyway so it would make sense to just fold that into the function itself and pass the zone and order as arguments instead of the free area. In order to be able to reference the zone we need to move the declaration of the functions down so that we have the zone defined before we define the list manipulation functions. Since the functions are only used in the file mm/page_alloc.c we can just move them there to reduce noise in the header. Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Pankaj Gupta <pagupta@redhat.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Nitesh Narayan Lal <nitesh@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Wang <wei.w.wang@intel.com> Cc: Yang Zhang <yang.zhang.wz@gmail.com> Cc: wei qi <weiqi4@huawei.com> Link: http://lkml.kernel.org/r/20200211224613.29318.43080.stgit@localhost.localdomain Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
a2129f24 |
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06-Apr-2020 |
Alexander Duyck <alexander.h.duyck@linux.intel.com> |
mm: adjust shuffle code to allow for future coalescing Patch series "mm / virtio: Provide support for free page reporting", v17. This series provides an asynchronous means of reporting free guest pages to a hypervisor so that the memory associated with those pages can be dropped and reused by other processes and/or guests on the host. Using this it is possible to avoid unnecessary I/O to disk and greatly improve performance in the case of memory overcommit on the host. When enabled we will be performing a scan of free memory every 2 seconds while pages of sufficiently high order are being freed. In each pass at least one sixteenth of each free list will be reported. By doing this we avoid racing against other threads that may be causing a high amount of memory churn. The lowest page order currently scanned when reporting pages is pageblock_order so that this feature will not interfere with the use of Transparent Huge Pages in the case of virtualization. Currently this is only in use by virtio-balloon however there is the hope that at some point in the future other hypervisors might be able to make use of it. In the virtio-balloon/QEMU implementation the hypervisor is currently using MADV_DONTNEED to indicate to the host kernel that the page is currently free. It will be zeroed and faulted back into the guest the next time the page is accessed. To track if a page is reported or not the Uptodate flag was repurposed and used as a Reported flag for Buddy pages. We walk though the free list isolating pages and adding them to the scatterlist until we either encounter the end of the list or have processed at least one sixteenth of the pages that were listed in nr_free prior to us starting. If we fill the scatterlist before we reach the end of the list we rotate the list so that the first unreported page we encounter is moved to the head of the list as that is where we will resume after we have freed the reported pages back into the tail of the list. Below are the results from various benchmarks. I primarily focused on two tests. The first is the will-it-scale/page_fault2 test, and the other is a modified version of will-it-scale/page_fault1 that was enabled to use THP. I did this as it allows for better visibility into different parts of the memory subsystem. The guest is running with 32G for RAM on one node of a E5-2630 v3. The host has had some features such as CPU turbo disabled in the BIOS. Test page_fault1 (THP) page_fault2 Name tasks Process Iter STDEV Process Iter STDEV Baseline 1 1012402.50 0.14% 361855.25 0.81% 16 8827457.25 0.09% 3282347.00 0.34% Patches Applied 1 1007897.00 0.23% 361887.00 0.26% 16 8784741.75 0.39% 3240669.25 0.48% Patches Enabled 1 1010227.50 0.39% 359749.25 0.56% 16 8756219.00 0.24% 3226608.75 0.97% Patches Enabled 1 1050982.00 4.26% 357966.25 0.14% page shuffle 16 8672601.25 0.49% 3223177.75 0.40% Patches enabled 1 1003238.00 0.22% 360211.00 0.22% shuffle w/ RFC 16 8767010.50 0.32% 3199874.00 0.71% The results above are for a baseline with a linux-next-20191219 kernel, that kernel with this patch set applied but page reporting disabled in virtio-balloon, the patches applied and page reporting fully enabled, the patches enabled with page shuffling enabled, and the patches applied with page shuffling enabled and an RFC patch that makes used of MADV_FREE in QEMU. These results include the deviation seen between the average value reported here versus the high and/or low value. I observed that during the test memory usage for the first three tests never dropped whereas with the patches fully enabled the VM would drop to using only a few GB of the host's memory when switching from memhog to page fault tests. Any of the overhead visible with this patch set enabled seems due to page faults caused by accessing the reported pages and the host zeroing the page before giving it back to the guest. This overhead is much more visible when using THP than with standard 4K pages. In addition page shuffling seemed to increase the amount of faults generated due to an increase in memory churn. The overehad is reduced when using MADV_FREE as we can avoid the extra zeroing of the pages when they are reintroduced to the host, as can be seen when the RFC is applied with shuffling enabled. The overall guest size is kept fairly small to only a few GB while the test is running. If the host memory were oversubscribed this patch set should result in a performance improvement as swapping memory in the host can be avoided. A brief history on the background of free page reporting can be found at: https://lore.kernel.org/lkml/29f43d5796feed0dec8e8bb98b187d9dac03b900.camel@linux.intel.com/ This patch (of 9): Move the head/tail adding logic out of the shuffle code and into the __free_one_page function since ultimately that is where it is really needed anyway. By doing this we should be able to reduce the overhead and can consolidate all of the list addition bits in one spot. Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: David Hildenbrand <david@redhat.com> Cc: Yang Zhang <yang.zhang.wz@gmail.com> Cc: Pankaj Gupta <pagupta@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Nitesh Narayan Lal <nitesh@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Wei Wang <wei.w.wang@intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Oscar Salvador <osalvador@suse.de> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: wei qi <weiqi4@huawei.com> Link: http://lkml.kernel.org/r/20200211224602.29318.84523.stgit@localhost.localdomain Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e03d1f78 |
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01-Apr-2020 |
Pingfan Liu <kernelfans@gmail.com> |
mm/sparse: rename pfn_present() to pfn_in_present_section() After introducing mem sub section concept, pfn_present() loses its literal meaning, and will not be necessary a truth on partial populated mem section. Since all of the callers use it to judge an absent section, it is better to rename pfn_present() as pfn_in_present_section(). Signed-off-by: Pingfan Liu <kernelfans@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Cc: Dan Williams <dan.j.williams@intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Leonardo Bras <leonardo@linux.ibm.com> Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com> Cc: Nathan Lynch <nathanl@linux.ibm.com> Link: http://lkml.kernel.org/r/1581919110-29575-1-git-send-email-kernelfans@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1970dc6f |
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01-Apr-2020 |
John Hubbard <jhubbard@nvidia.com> |
mm/gup: /proc/vmstat: pin_user_pages (FOLL_PIN) reporting Now that pages are "DMA-pinned" via pin_user_page*(), and unpinned via unpin_user_pages*(), we need some visibility into whether all of this is working correctly. Add two new fields to /proc/vmstat: nr_foll_pin_acquired nr_foll_pin_released These are documented in Documentation/core-api/pin_user_pages.rst. They represent the number of pages (since boot time) that have been pinned ("nr_foll_pin_acquired") and unpinned ("nr_foll_pin_released"), via pin_user_pages*() and unpin_user_pages*(). In the absence of long-running DMA or RDMA operations that hold pages pinned, the above two fields will normally be equal to each other. Also: update Documentation/core-api/pin_user_pages.rst, to remove an earlier (now confirmed untrue) claim about a performance problem with /proc/vmstat. Also: update Documentation/core-api/pin_user_pages.rst to rename the new /proc/vmstat entries, to the names listed here. Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200211001536.1027652-9-jhubbard@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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9ffc1d19 |
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30-Jan-2020 |
Dan Williams <dan.j.williams@intel.com> |
mm/memremap_pages: Introduce memremap_compat_align() The "sub-section memory hotplug" facility allows memremap_pages() users like libnvdimm to compensate for hardware platforms like x86 that have a section size larger than their hardware memory mapping granularity. The compensation that sub-section support affords is being tolerant of physical memory resources shifting by units smaller (64MiB on x86) than the memory-hotplug section size (128 MiB). Where the platform physical-memory mapping granularity is limited by the number and capability of address-decode-registers in the memory controller. While the sub-section support allows memremap_pages() to operate on sub-section (2MiB) granularity, the Power architecture may still require 16MiB alignment on "!radix_enabled()" platforms. In order for libnvdimm to be able to detect and manage this per-arch limitation, introduce memremap_compat_align() as a common minimum alignment across all driver-facing memory-mapping interfaces, and let Power override it to 16MiB in the "!radix_enabled()" case. The assumption / requirement for 16MiB to be a viable memremap_compat_align() value is that Power does not have platforms where its equivalent of address-decode-registers never hardware remaps a persistent memory resource on smaller than 16MiB boundaries. Note that I tried my best to not add a new Kconfig symbol, but header include entanglements defeated the #ifndef memremap_compat_align design pattern and the need to export it defeats the __weak design pattern for arch overrides. Based on an initial patch by Aneesh. Link: http://lore.kernel.org/r/CAPcyv4gBGNP95APYaBcsocEa50tQj9b5h__83vgngjq3ouGX_Q@mail.gmail.com Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Reported-by: Jeff Moyer <jmoyer@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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4c605881 |
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03-Feb-2020 |
David Hildenbrand <david@redhat.com> |
mm: factor out next_present_section_nr() Let's move it to the header and use the shorter variant from mm/page_alloc.c (the original one will also check "__highest_present_section_nr + 1", which is not necessary). While at it, make the section_nr in next_pfn() const. In next_pfn(), we now return section_nr_to_pfn(-1) instead of -1 once we exceed __highest_present_section_nr, which doesn't make a difference in the caller as it is big enough (>= all sane end_pfn). Link: http://lkml.kernel.org/r/20200113144035.10848-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Baoquan He <bhe@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: "Jin, Zhi" <zhi.jin@intel.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Tatashin <pasha.tatashin@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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0a3c5772 |
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30-Jan-2020 |
Hao Lee <haolee.swjtu@gmail.com> |
mm: fix comments related to node reclaim As zone reclaim has been replaced by node reclaim, this patch fixes related comments. Link: http://lkml.kernel.org/r/20191126141346.GA22665@haolee.github.io Signed-off-by: Hao Lee <haolee.swjtu@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4a87e2a2 |
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13-Jan-2020 |
Roman Gushchin <guro@fb.com> |
mm: memcg/slab: fix percpu slab vmstats flushing Currently slab percpu vmstats are flushed twice: during the memcg offlining and just before freeing the memcg structure. Each time percpu counters are summed, added to the atomic counterparts and propagated up by the cgroup tree. The second flushing is required due to how recursive vmstats are implemented: counters are batched in percpu variables on a local level, and once a percpu value is crossing some predefined threshold, it spills over to atomic values on the local and each ascendant levels. It means that without flushing some numbers cached in percpu variables will be dropped on floor each time a cgroup is destroyed. And with uptime the error on upper levels might become noticeable. The first flushing aims to make counters on ancestor levels more precise. Dying cgroups may resume in the dying state for a long time. After kmem_cache reparenting which is performed during the offlining slab counters of the dying cgroup don't have any chances to be updated, because any slab operations will be performed on the parent level. It means that the inaccuracy caused by percpu batching will not decrease up to the final destruction of the cgroup. By the original idea flushing slab counters during the offlining should minimize the visible inaccuracy of slab counters on the parent level. The problem is that percpu counters are not zeroed after the first flushing. So every cached percpu value is summed twice. It creates a small error (up to 32 pages per cpu, but usually less) which accumulates on parent cgroup level. After creating and destroying of thousands of child cgroups, slab counter on parent level can be way off the real value. For now, let's just stop flushing slab counters on memcg offlining. It can't be done correctly without scheduling a work on each cpu: reading and zeroing it during css offlining can race with an asynchronous update, which doesn't expect values to be changed underneath. With this change, slab counters on parent level will become eventually consistent. Once all dying children are gone, values are correct. And if not, the error is capped by 32 * NR_CPUS pages per dying cgroup. It's not perfect, as slab are reparented, so any updates after the reparenting will happen on the parent level. It means that if a slab page was allocated, a counter on child level was bumped, then the page was reparented and freed, the annihilation of positive and negative counter values will not happen until the child cgroup is released. It makes slab counters different from others, and it might want us to implement flushing in a correct form again. But it's also a question of performance: scheduling a work on each cpu isn't free, and it's an open question if the benefit of having more accurate counters is worth it. We might also consider flushing all counters on offlining, not only slab counters. So let's fix the main problem now: make the slab counters eventually consistent, so at least the error won't grow with uptime (or more precisely the number of created and destroyed cgroups). And think about the accuracy of counters separately. Link: http://lkml.kernel.org/r/20191220042728.1045881-1-guro@fb.com Fixes: bee07b33db78 ("mm: memcontrol: flush percpu slab vmstats on kmem offlining") Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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84218b55 |
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30-Nov-2019 |
Hao Lee <haolee.swjtu@gmail.com> |
mm: fix struct member name in function comments The member in struct zonelist is _zonerefs instead of zones. Link: http://lkml.kernel.org/r/20190927144049.GA29622@haolee.github.io Signed-off-by: Hao Lee <haolee.swjtu@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Wei Yang <richardw.yang@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b91ac374 |
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30-Nov-2019 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: vmscan: enforce inactive:active ratio at the reclaim root We split the LRU lists into inactive and an active parts to maximize workingset protection while allowing just enough inactive cache space to faciltate readahead and writeback for one-off file accesses (e.g. a linear scan through a file, or logging); or just enough inactive anon to maintain recent reference information when reclaim needs to swap. With cgroups and their nested LRU lists, we currently don't do this correctly. While recursive cgroup reclaim establishes a relative LRU order among the pages of all involved cgroups, inactive:active size decisions are done on a per-cgroup level. As a result, we'll reclaim a cgroup's workingset when it doesn't have cold pages, even when one of its siblings has plenty of it that should be reclaimed first. For example: workload A has 50M worth of hot cache but doesn't do any one-off file accesses; meanwhile, parallel workload B scans files and rarely accesses the same page twice. If these workloads were to run in an uncgrouped system, A would be protected from the high rate of cache faults from B. But if they were put in parallel cgroups for memory accounting purposes, B's fast cache fault rate would push out the hot cache pages of A. This is unexpected and undesirable - the "scan resistance" of the page cache is broken. This patch moves inactive:active size balancing decisions to the root of reclaim - the same level where the LRU order is established. It does this by looking at the recursive size of the inactive and the active file sets of the cgroup subtree at the beginning of the reclaim cycle, and then making a decision - scan or skip active pages - that applies throughout the entire run and to every cgroup involved. With that in place, in the test above, the VM will recognize that there are plenty of inactive pages in the combined cache set of workloads A and B and prefer the one-off cache in B over the hot pages in A. The scan resistance of the cache is restored. [cai@lca.pw: fix some -Wenum-conversion warnings] Link: http://lkml.kernel.org/r/1573848697-29262-1-git-send-email-cai@lca.pw Link: http://lkml.kernel.org/r/20191107205334.158354-4-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Rik van Riel <riel@surriel.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1b05117d |
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30-Nov-2019 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: vmscan: harmonize writeback congestion tracking for nodes & memcgs The current writeback congestion tracking has separate flags for kswapd reclaim (node level) and cgroup limit reclaim (memcg-node level). This is unnecessarily complicated: the lruvec is an existing abstraction layer for that node-memcg intersection. Introduce lruvec->flags and LRUVEC_CONGESTED. Then track that at the reclaim root level, which is either the NUMA node for global reclaim, or the cgroup-node intersection for cgroup reclaim. Link: http://lkml.kernel.org/r/20191022144803.302233-9-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Roman Gushchin <guro@fb.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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867e5e1d |
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30-Nov-2019 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: clean up and clarify lruvec lookup procedure There is a per-memcg lruvec and a NUMA node lruvec. Which one is being used is somewhat confusing right now, and it's easy to make mistakes - especially when it comes to global reclaim. How it works: when memory cgroups are enabled, we always use the root_mem_cgroup's per-node lruvecs. When memory cgroups are not compiled in or disabled at runtime, we use pgdat->lruvec. Document that in a comment. Due to the way the reclaim code is generalized, all lookups use the mem_cgroup_lruvec() helper function, and nobody should have to find the right lruvec manually right now. But to avoid future mistakes, rename the pgdat->lruvec member to pgdat->__lruvec and delete the convenience wrapper that suggests it's a commonly accessed member. While in this area, swap the mem_cgroup_lruvec() argument order. The name suggests a memcg operation, yet it takes a pgdat first and a memcg second. I have to double take every time I call this. Fix that. Link: http://lkml.kernel.org/r/20191022144803.302233-3-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Cc: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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653e003d |
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30-Nov-2019 |
Hao Lee <haolee.swjtu@gmail.com> |
include/linux/mmzone.h: fix comment for ISOLATE_UNMAPPED macro Both file-backed pages and anonymous pages can be unmapped. ISOLATE_UNMAPPED is not just for file-backed pages. Link: http://lkml.kernel.org/r/20191024151621.GA20400@haolee.github.io Signed-off-by: Hao Lee <haolee.swjtu@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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734f9246 |
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11-Sep-2019 |
Nicolas Saenz Julienne <nsaenzjulienne@suse.de> |
mm: refresh ZONE_DMA and ZONE_DMA32 comments in 'enum zone_type' These zones usage has evolved with time and the comments were outdated. This joins both ZONE_DMA and ZONE_DMA32 explanation and gives up to date examples on how they are used on different architectures. Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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364c1eeb |
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23-Sep-2019 |
Yang Shi <yang.shi@linux.alibaba.com> |
mm: thp: extract split_queue_* into a struct Patch series "Make deferred split shrinker memcg aware", v6. Currently THP deferred split shrinker is not memcg aware, this may cause premature OOM with some configuration. For example the below test would run into premature OOM easily: $ cgcreate -g memory:thp $ echo 4G > /sys/fs/cgroup/memory/thp/memory/limit_in_bytes $ cgexec -g memory:thp transhuge-stress 4000 transhuge-stress comes from kernel selftest. It is easy to hit OOM, but there are still a lot THP on the deferred split queue, memcg direct reclaim can't touch them since the deferred split shrinker is not memcg aware. Convert deferred split shrinker memcg aware by introducing per memcg deferred split queue. The THP should be on either per node or per memcg deferred split queue if it belongs to a memcg. When the page is immigrated to the other memcg, it will be immigrated to the target memcg's deferred split queue too. Reuse the second tail page's deferred_list for per memcg list since the same THP can't be on multiple deferred split queues. Make deferred split shrinker not depend on memcg kmem since it is not slab. It doesn't make sense to not shrink THP even though memcg kmem is disabled. With the above change the test demonstrated above doesn't trigger OOM even though with cgroup.memory=nokmem. This patch (of 4): Put split_queue, split_queue_lock and split_queue_len into a struct in order to reduce code duplication when we convert deferred_split to memcg aware in the later patches. Link: http://lkml.kernel.org/r/1565144277-36240-2-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Suggested-by: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Qian Cai <cai@lca.pw> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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60fbf0ab |
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23-Sep-2019 |
Song Liu <songliubraving@fb.com> |
mm,thp: stats for file backed THP In preparation for non-shmem THP, this patch adds a few stats and exposes them in /proc/meminfo, /sys/bus/node/devices/<node>/meminfo, and /proc/<pid>/task/<tid>/smaps. This patch is mostly a rewrite of Kirill A. Shutemov's earlier version: https://lkml.kernel.org/r/20170126115819.58875-5-kirill.shutemov@linux.intel.com/ Link: http://lkml.kernel.org/r/20190801184244.3169074-5-songliubraving@fb.com Signed-off-by: Song Liu <songliubraving@fb.com> Acked-by: Rik van Riel <riel@surriel.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Hillf Danton <hdanton@sina.com> Cc: Hugh Dickins <hughd@google.com> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bee07b33 |
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30-Aug-2019 |
Roman Gushchin <guro@fb.com> |
mm: memcontrol: flush percpu slab vmstats on kmem offlining I've noticed that the "slab" value in memory.stat is sometimes 0, even if some children memory cgroups have a non-zero "slab" value. The following investigation showed that this is the result of the kmem_cache reparenting in combination with the per-cpu batching of slab vmstats. At the offlining some vmstat value may leave in the percpu cache, not being propagated upwards by the cgroup hierarchy. It means that stats on ancestor levels are lower than actual. Later when slab pages are released, the precise number of pages is substracted on the parent level, making the value negative. We don't show negative values, 0 is printed instead. To fix this issue, let's flush percpu slab memcg and lruvec stats on memcg offlining. This guarantees that numbers on all ancestor levels are accurate and match the actual number of outstanding slab pages. Link: http://lkml.kernel.org/r/20190819202338.363363-3-guro@fb.com Fixes: fb2f2b0adb98 ("mm: memcg/slab: reparent memcg kmem_caches on cgroup removal") Signed-off-by: Roman Gushchin <guro@fb.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a3619190 |
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18-Jul-2019 |
Dan Williams <dan.j.williams@intel.com> |
libnvdimm/pfn: stop padding pmem namespaces to section alignment Now that the mm core supports section-unaligned hotplug of ZONE_DEVICE memory, we no longer need to add padding at pfn/dax device creation time. The kernel will still honor padding established by older kernels. Link: http://lkml.kernel.org/r/156092356588.979959.6793371748950931916.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reported-by: Jeff Moyer <jmoyer@redhat.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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46d945ae |
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18-Jul-2019 |
Dan Williams <dan.j.williams@intel.com> |
mm: kill is_dev_zone() helper Given there are no more usages of is_dev_zone() outside of 'ifdef CONFIG_ZONE_DEVICE' protection, kill off the compilation helper. Link: http://lkml.kernel.org/r/156092353211.979959.1489004866360828964.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Wei Yang <richardw.yang@linux.intel.com> Acked-by: David Hildenbrand <david@redhat.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Cc: Michal Hocko <mhocko@suse.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
f46edbd1 |
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18-Jul-2019 |
Dan Williams <dan.j.williams@intel.com> |
mm/sparsemem: add helpers track active portions of a section at boot Prepare for hot{plug,remove} of sub-ranges of a section by tracking a sub-section active bitmask, each bit representing a PMD_SIZE span of the architecture's memory hotplug section size. The implications of a partially populated section is that pfn_valid() needs to go beyond a valid_section() check and either determine that the section is an "early section", or read the sub-section active ranges from the bitmask. The expectation is that the bitmask (subsection_map) fits in the same cacheline as the valid_section() / early_section() data, so the incremental performance overhead to pfn_valid() should be negligible. The rationale for using early_section() to short-ciruit the subsection_map check is that there are legacy code paths that use pfn_valid() at section granularity before validating the pfn against pgdat data. So, the early_section() check allows those traditional assumptions to persist while also permitting subsection_map to tell the truth for purposes of populating the unused portions of early sections with PMEM and other ZONE_DEVICE mappings. Link: http://lkml.kernel.org/r/156092350874.979959.18185938451405518285.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reported-by: Qian Cai <cai@lca.pw> Tested-by: Jane Chu <jane.chu@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
326e1b8f |
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18-Jul-2019 |
Dan Williams <dan.j.williams@intel.com> |
mm/sparsemem: introduce a SECTION_IS_EARLY flag In preparation for sub-section hotplug, track whether a given section was created during early memory initialization, or later via memory hotplug. This distinction is needed to maintain the coarse expectation that pfn_valid() returns true for any pfn within a given section even if that section has pages that are reserved from the page allocator. For example one of the of goals of subsection hotplug is to support cases where the system physical memory layout collides System RAM and PMEM within a section. Several pfn_valid() users expect to just check if a section is valid, but they are not careful to check if the given pfn is within a "System RAM" boundary and instead expect pgdat information to further validate the pfn. Rather than unwind those paths to make their pfn_valid() queries more precise a follow on patch uses the SECTION_IS_EARLY flag to maintain the traditional expectation that pfn_valid() returns true for all early sections. Link: https://lore.kernel.org/lkml/1560366952-10660-1-git-send-email-cai@lca.pw/ Link: http://lkml.kernel.org/r/156092350358.979959.5817209875548072819.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reported-by: Qian Cai <cai@lca.pw> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: David Hildenbrand <david@redhat.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
f1eca35a |
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18-Jul-2019 |
Dan Williams <dan.j.williams@intel.com> |
mm/sparsemem: introduce struct mem_section_usage Patch series "mm: Sub-section memory hotplug support", v10. The memory hotplug section is an arbitrary / convenient unit for memory hotplug. 'Section-size' units have bled into the user interface ('memblock' sysfs) and can not be changed without breaking existing userspace. The section-size constraint, while mostly benign for typical memory hotplug, has and continues to wreak havoc with 'device-memory' use cases, persistent memory (pmem) in particular. Recall that pmem uses devm_memremap_pages(), and subsequently arch_add_memory(), to allocate a 'struct page' memmap for pmem. However, it does not use the 'bottom half' of memory hotplug, i.e. never marks pmem pages online and never exposes the userspace memblock interface for pmem. This leaves an opening to redress the section-size constraint. To date, the libnvdimm subsystem has attempted to inject padding to satisfy the internal constraints of arch_add_memory(). Beyond complicating the code, leading to bugs [2], wasting memory, and limiting configuration flexibility, the padding hack is broken when the platform changes this physical memory alignment of pmem from one boot to the next. Device failure (intermittent or permanent) and physical reconfiguration are events that can cause the platform firmware to change the physical placement of pmem on a subsequent boot, and device failure is an everyday event in a data-center. It turns out that sections are only a hard requirement of the user-facing interface for memory hotplug and with a bit more infrastructure sub-section arch_add_memory() support can be added for kernel internal usages like devm_memremap_pages(). Here is an analysis of the current design assumptions in the current code and how they are addressed in the new implementation: Current design assumptions: - Sections that describe boot memory (early sections) are never unplugged / removed. - pfn_valid(), in the CONFIG_SPARSEMEM_VMEMMAP=y, case devolves to a valid_section() check - __add_pages() and helper routines assume all operations occur in PAGES_PER_SECTION units. - The memblock sysfs interface only comprehends full sections New design assumptions: - Sections are instrumented with a sub-section bitmask to track (on x86) individual 2MB sub-divisions of a 128MB section. - Partially populated early sections can be extended with additional sub-sections, and those sub-sections can be removed with arch_remove_memory(). With this in place we no longer lose usable memory capacity to padding. - pfn_valid() is updated to look deeper than valid_section() to also check the active-sub-section mask. This indication is in the same cacheline as the valid_section() so the performance impact is expected to be negligible. So far the lkp robot has not reported any regressions. - Outside of the core vmemmap population routines which are replaced, other helper routines like shrink_{zone,pgdat}_span() are updated to handle the smaller granularity. Core memory hotplug routines that deal with online memory are not touched. - The existing memblock sysfs user api guarantees / assumptions are not touched since this capability is limited to !online !memblock-sysfs-accessible sections. Meanwhile the issue reports continue to roll in from users that do not understand when and how the 128MB constraint will bite them. The current implementation relied on being able to support at least one misaligned namespace, but that immediately falls over on any moderately complex namespace creation attempt. Beyond the initial problem of 'System RAM' colliding with pmem, and the unsolvable problem of physical alignment changes, Linux is now being exposed to platforms that collide pmem ranges with other pmem ranges by default [3]. In short, devm_memremap_pages() has pushed the venerable section-size constraint past the breaking point, and the simplicity of section-aligned arch_add_memory() is no longer tenable. These patches are exposed to the kbuild robot on a subsection-v10 branch [4], and a preview of the unit test for this functionality is available on the 'subsection-pending' branch of ndctl [5]. [2]: https://lore.kernel.org/r/155000671719.348031.2347363160141119237.stgit@dwillia2-desk3.amr.corp.intel.com [3]: https://github.com/pmem/ndctl/issues/76 [4]: https://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm.git/log/?h=subsection-v10 [5]: https://github.com/pmem/ndctl/commit/7c59b4867e1c This patch (of 13): Towards enabling memory hotplug to track partial population of a section, introduce 'struct mem_section_usage'. A pointer to a 'struct mem_section_usage' instance replaces the existing pointer to a 'pageblock_flags' bitmap. Effectively it adds one more 'unsigned long' beyond the 'pageblock_flags' (usemap) allocation to house a new 'subsection_map' bitmap. The new bitmap enables the memory hot{plug,remove} implementation to act on incremental sub-divisions of a section. SUBSECTION_SHIFT is defined as global constant instead of per-architecture value like SECTION_SIZE_BITS in order to allow cross-arch compatibility of subsection users. Specifically a common subsection size allows for the possibility that persistent memory namespace configurations be made compatible across architectures. The primary motivation for this functionality is to support platforms that mix "System RAM" and "Persistent Memory" within a single section, or multiple PMEM ranges with different mapping lifetimes within a single section. The section restriction for hotplug has caused an ongoing saga of hacks and bugs for devm_memremap_pages() users. Beyond the fixups to teach existing paths how to retrieve the 'usemap' from a section, and updates to usemap allocation path, there are no expected behavior changes. Link: http://lkml.kernel.org/r/156092349845.979959.73333291612799019.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Wei Yang <richardw.yang@linux.intel.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Qian Cai <cai@lca.pw> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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2491f0a2 |
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18-Jul-2019 |
David Hildenbrand <david@redhat.com> |
mm: section numbers use the type "unsigned long" Patch series "mm: Further memory block device cleanups", v1. Some further cleanups around memory block devices. Especially, clean up and simplify walk_memory_range(). Including some other minor cleanups. This patch (of 6): We are using a mixture of "int" and "unsigned long". Let's make this consistent by using "unsigned long" everywhere. We'll do the same with memory block ids next. While at it, turn the "unsigned long i" in removable_show() into an int - sections_per_block is an int. [akpm@linux-foundation.org: s/unsigned long i/unsigned long nr/] [david@redhat.com: v3] Link: http://lkml.kernel.org/r/20190620183139.4352-2-david@redhat.com Link: http://lkml.kernel.org/r/20190614100114.311-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Arun KS <arunks@codeaurora.org> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Baoquan He <bhe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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97500a4a |
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14-May-2019 |
Dan Williams <dan.j.williams@intel.com> |
mm: maintain randomization of page free lists When freeing a page with an order >= shuffle_page_order randomly select the front or back of the list for insertion. While the mm tries to defragment physical pages into huge pages this can tend to make the page allocator more predictable over time. Inject the front-back randomness to preserve the initial randomness established by shuffle_free_memory() when the kernel was booted. The overhead of this manipulation is constrained by only being applied for MAX_ORDER sized pages by default. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/154899812788.3165233.9066631950746578517.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Robert Elliott <elliott@hpe.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b03641af |
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14-May-2019 |
Dan Williams <dan.j.williams@intel.com> |
mm: move buddy list manipulations into helpers In preparation for runtime randomization of the zone lists, take all (well, most of) the list_*() functions in the buddy allocator and put them in helper functions. Provide a common control point for injecting additional behavior when freeing pages. [dan.j.williams@intel.com: fix buddy list helpers] Link: http://lkml.kernel.org/r/155033679702.1773410.13041474192173212653.stgit@dwillia2-desk3.amr.corp.intel.com [vbabka@suse.cz: remove del_page_from_free_area() migratetype parameter] Link: http://lkml.kernel.org/r/4672701b-6775-6efd-0797-b6242591419e@suse.cz Link: http://lkml.kernel.org/r/154899812264.3165233.5219320056406926223.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Kees Cook <keescook@chromium.org> Cc: Keith Busch <keith.busch@intel.com> Cc: Robert Elliott <elliott@hpe.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e900a918 |
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14-May-2019 |
Dan Williams <dan.j.williams@intel.com> |
mm: shuffle initial free memory to improve memory-side-cache utilization Patch series "mm: Randomize free memory", v10. This patch (of 3): Randomization of the page allocator improves the average utilization of a direct-mapped memory-side-cache. Memory side caching is a platform capability that Linux has been previously exposed to in HPC (high-performance computing) environments on specialty platforms. In that instance it was a smaller pool of high-bandwidth-memory relative to higher-capacity / lower-bandwidth DRAM. Now, this capability is going to be found on general purpose server platforms where DRAM is a cache in front of higher latency persistent memory [1]. Robert offered an explanation of the state of the art of Linux interactions with memory-side-caches [2], and I copy it here: It's been a problem in the HPC space: http://www.nersc.gov/research-and-development/knl-cache-mode-performance-coe/ A kernel module called zonesort is available to try to help: https://software.intel.com/en-us/articles/xeon-phi-software and this abandoned patch series proposed that for the kernel: https://lkml.kernel.org/r/20170823100205.17311-1-lukasz.daniluk@intel.com Dan's patch series doesn't attempt to ensure buffers won't conflict, but also reduces the chance that the buffers will. This will make performance more consistent, albeit slower than "optimal" (which is near impossible to attain in a general-purpose kernel). That's better than forcing users to deploy remedies like: "To eliminate this gradual degradation, we have added a Stream measurement to the Node Health Check that follows each job; nodes are rebooted whenever their measured memory bandwidth falls below 300 GB/s." A replacement for zonesort was merged upstream in commit cc9aec03e58f ("x86/numa_emulation: Introduce uniform split capability"). With this numa_emulation capability, memory can be split into cache sized ("near-memory" sized) numa nodes. A bind operation to such a node, and disabling workloads on other nodes, enables full cache performance. However, once the workload exceeds the cache size then cache conflicts are unavoidable. While HPC environments might be able to tolerate time-scheduling of cache sized workloads, for general purpose server platforms, the oversubscribed cache case will be the common case. The worst case scenario is that a server system owner benchmarks a workload at boot with an un-contended cache only to see that performance degrade over time, even below the average cache performance due to excessive conflicts. Randomization clips the peaks and fills in the valleys of cache utilization to yield steady average performance. Here are some performance impact details of the patches: 1/ An Intel internal synthetic memory bandwidth measurement tool, saw a 3X speedup in a contrived case that tries to force cache conflicts. The contrived cased used the numa_emulation capability to force an instance of the benchmark to be run in two of the near-memory sized numa nodes. If both instances were placed on the same emulated they would fit and cause zero conflicts. While on separate emulated nodes without randomization they underutilized the cache and conflicted unnecessarily due to the in-order allocation per node. 2/ A well known Java server application benchmark was run with a heap size that exceeded cache size by 3X. The cache conflict rate was 8% for the first run and degraded to 21% after page allocator aging. With randomization enabled the rate levelled out at 11%. 3/ A MongoDB workload did not observe measurable difference in cache-conflict rates, but the overall throughput dropped by 7% with randomization in one case. 4/ Mel Gorman ran his suite of performance workloads with randomization enabled on platforms without a memory-side-cache and saw a mix of some improvements and some losses [3]. While there is potentially significant improvement for applications that depend on low latency access across a wide working-set, the performance may be negligible to negative for other workloads. For this reason the shuffle capability defaults to off unless a direct-mapped memory-side-cache is detected. Even then, the page_alloc.shuffle=0 parameter can be specified to disable the randomization on those systems. Outside of memory-side-cache utilization concerns there is potentially security benefit from randomization. Some data exfiltration and return-oriented-programming attacks rely on the ability to infer the location of sensitive data objects. The kernel page allocator, especially early in system boot, has predictable first-in-first out behavior for physical pages. Pages are freed in physical address order when first onlined. Quoting Kees: "While we already have a base-address randomization (CONFIG_RANDOMIZE_MEMORY), attacks against the same hardware and memory layouts would certainly be using the predictability of allocation ordering (i.e. for attacks where the base address isn't important: only the relative positions between allocated memory). This is common in lots of heap-style attacks. They try to gain control over ordering by spraying allocations, etc. I'd really like to see this because it gives us something similar to CONFIG_SLAB_FREELIST_RANDOM but for the page allocator." While SLAB_FREELIST_RANDOM reduces the predictability of some local slab caches it leaves vast bulk of memory to be predictably in order allocated. However, it should be noted, the concrete security benefits are hard to quantify, and no known CVE is mitigated by this randomization. Introduce shuffle_free_memory(), and its helper shuffle_zone(), to perform a Fisher-Yates shuffle of the page allocator 'free_area' lists when they are initially populated with free memory at boot and at hotplug time. Do this based on either the presence of a page_alloc.shuffle=Y command line parameter, or autodetection of a memory-side-cache (to be added in a follow-on patch). The shuffling is done in terms of CONFIG_SHUFFLE_PAGE_ORDER sized free pages where the default CONFIG_SHUFFLE_PAGE_ORDER is MAX_ORDER-1 i.e. 10, 4MB this trades off randomization granularity for time spent shuffling. MAX_ORDER-1 was chosen to be minimally invasive to the page allocator while still showing memory-side cache behavior improvements, and the expectation that the security implications of finer granularity randomization is mitigated by CONFIG_SLAB_FREELIST_RANDOM. The performance impact of the shuffling appears to be in the noise compared to other memory initialization work. This initial randomization can be undone over time so a follow-on patch is introduced to inject entropy on page free decisions. It is reasonable to ask if the page free entropy is sufficient, but it is not enough due to the in-order initial freeing of pages. At the start of that process putting page1 in front or behind page0 still keeps them close together, page2 is still near page1 and has a high chance of being adjacent. As more pages are added ordering diversity improves, but there is still high page locality for the low address pages and this leads to no significant impact to the cache conflict rate. [1]: https://itpeernetwork.intel.com/intel-optane-dc-persistent-memory-operating-modes/ [2]: https://lkml.kernel.org/r/AT5PR8401MB1169D656C8B5E121752FC0F8AB120@AT5PR8401MB1169.NAMPRD84.PROD.OUTLOOK.COM [3]: https://lkml.org/lkml/2018/10/12/309 [dan.j.williams@intel.com: fix shuffle enable] Link: http://lkml.kernel.org/r/154943713038.3858443.4125180191382062871.stgit@dwillia2-desk3.amr.corp.intel.com [cai@lca.pw: fix SHUFFLE_PAGE_ALLOCATOR help texts] Link: http://lkml.kernel.org/r/20190425201300.75650-1-cai@lca.pw Link: http://lkml.kernel.org/r/154899811738.3165233.12325692939590944259.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Qian Cai <cai@lca.pw> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Robert Elliott <elliott@hpe.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
113b7dfd |
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13-May-2019 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: memcontrol: quarantine the mem_cgroup_[node_]nr_lru_pages() API Only memcg_numa_stat_show() uses those wrappers and the lru bitmasks, group them together. Link: http://lkml.kernel.org/r/20190228163020.24100-7-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Roman Gushchin <guro@fb.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
f4b7e272 |
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05-Mar-2019 |
Andrey Ryabinin <ryabinin.a.a@gmail.com> |
mm: remove zone_lru_lock() function, access ->lru_lock directly We have common pattern to access lru_lock from a page pointer: zone_lru_lock(page_zone(page)) Which is silly, because it unfolds to this: &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)]->zone_pgdat->lru_lock while we can simply do &NODE_DATA(page_to_nid(page))->lru_lock Remove zone_lru_lock() function, since it's only complicate things. Use 'page_pgdat(page)->lru_lock' pattern instead. [aryabinin@virtuozzo.com: a slightly better version of __split_huge_page()] Link: http://lkml.kernel.org/r/20190301121651.7741-1-aryabinin@virtuozzo.com Link: http://lkml.kernel.org/r/20190228083329.31892-2-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Rik van Riel <riel@surriel.com> Cc: William Kucharski <william.kucharski@oracle.com> Cc: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
8bb4e7a2 |
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05-Mar-2019 |
Wei Yang <richard.weiyang@gmail.com> |
mm: fix some typos in mm directory No functional change. Link: http://lkml.kernel.org/r/20190118235123.27843-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Pekka Enberg <penberg@kernel.org> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
e332f741 |
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05-Mar-2019 |
Mel Gorman <mgorman@techsingularity.net> |
mm, compaction: be selective about what pageblocks to clear skip hints Pageblock hints are cleared when compaction restarts or kswapd makes enough progress that it can sleep but it's over-eager in that the bit is cleared for migration sources with no LRU pages and migration targets with no free pages. As pageblock skip hint flushes are relatively rare and out-of-band with respect to kswapd, this patch makes a few more expensive checks to see if it's appropriate to even clear the bit. Every pageblock that is not cleared will avoid 512 pages being scanned unnecessarily on x86-64. The impact is variable with different workloads showing small differences in latency, success rates and scan rates. This is expected as clearing the hints is not that common but doing a small amount of work out-of-band to avoid a large amount of work in-band later is generally a good thing. Link: http://lkml.kernel.org/r/20190118175136.31341-22-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Qian Cai <cai@lca.pw> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: YueHaibing <yuehaibing@huawei.com> [cai@lca.pw: no stuck in __reset_isolation_pfn()] Link: http://lkml.kernel.org/r/20190206034732.75687-1-cai@lca.pw Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
73444bc4 |
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08-Jan-2019 |
Mel Gorman <mgorman@techsingularity.net> |
mm, page_alloc: do not wake kswapd with zone lock held syzbot reported the following regression in the latest merge window and it was confirmed by Qian Cai that a similar bug was visible from a different context. ====================================================== WARNING: possible circular locking dependency detected 4.20.0+ #297 Not tainted ------------------------------------------------------ syz-executor0/8529 is trying to acquire lock: 000000005e7fb829 (&pgdat->kswapd_wait){....}, at: __wake_up_common_lock+0x19e/0x330 kernel/sched/wait.c:120 but task is already holding lock: 000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: spin_lock include/linux/spinlock.h:329 [inline] 000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: rmqueue_bulk mm/page_alloc.c:2548 [inline] 000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: __rmqueue_pcplist mm/page_alloc.c:3021 [inline] 000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: rmqueue_pcplist mm/page_alloc.c:3050 [inline] 000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: rmqueue mm/page_alloc.c:3072 [inline] 000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: get_page_from_freelist+0x1bae/0x52a0 mm/page_alloc.c:3491 It appears to be a false positive in that the only way the lock ordering should be inverted is if kswapd is waking itself and the wakeup allocates debugging objects which should already be allocated if it's kswapd doing the waking. Nevertheless, the possibility exists and so it's best to avoid the problem. This patch flags a zone as needing a kswapd using the, surprisingly, unused zone flag field. The flag is read without the lock held to do the wakeup. It's possible that the flag setting context is not the same as the flag clearing context or for small races to occur. However, each race possibility is harmless and there is no visible degredation in fragmentation treatment. While zone->flag could have continued to be unused, there is potential for moving some existing fields into the flags field instead. Particularly read-mostly ones like zone->initialized and zone->contiguous. Link: http://lkml.kernel.org/r/20190103225712.GJ31517@techsingularity.net Fixes: 1c30844d2dfe ("mm: reclaim small amounts of memory when an external fragmentation event occurs") Reported-by: syzbot+93d94a001cfbce9e60e1@syzkaller.appspotmail.com Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Qian Cai <cai@lca.pw> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
fa004ab7 |
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28-Dec-2018 |
Wei Yang <richard.weiyang@gmail.com> |
mm, hotplug: move init_currently_empty_zone() under zone_span_lock protection During online_pages phase, pgdat->nr_zones will be updated in case this zone is empty. Currently the online_pages phase is protected by the global locks (device_device_hotplug_lock and mem_hotplug_lock), which ensures there is no contention during the update of nr_zones. These global locks introduces scalability issues (especially the second one), which slow down code relying on get_online_mems(). This is also a preparation for not having to rely on get_online_mems() but instead some more fine grained locks. The patch moves init_currently_empty_zone under both zone_span_writelock and pgdat_resize_lock because both the pgdat state is changed (nr_zones) and the zone's start_pfn. Also this patch changes the documentation of node_size_lock to include the protection of nr_zones. Link: http://lkml.kernel.org/r/20181203205016.14123-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
83af6588 |
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28-Dec-2018 |
Wei Yang <richard.weiyang@gmail.com> |
mm, sparse: drop pgdat_resize_lock in sparse_add/remove_one_section() pgdat_resize_lock is used to protect pgdat's memory region information like: node_start_pfn, node_present_pages, etc. While in function sparse_add/remove_one_section(), pgdat_resize_lock is used to protect initialization/release of one mem_section. This looks not proper. These code paths are currently protected by mem_hotplug_lock currently but should there ever be any reason for locking at the sparse layer a dedicated lock should be introduced. Following is the current call trace of sparse_add/remove_one_section() mem_hotplug_begin() arch_add_memory() add_pages() __add_pages() __add_section() sparse_add_one_section() mem_hotplug_done() mem_hotplug_begin() arch_remove_memory() __remove_pages() __remove_section() sparse_remove_one_section() mem_hotplug_done() The comment above the pgdat_resize_lock also mentions "Holding this will also guarantee that any pfn_valid() stays that way.", which is true with the current implementation and false after this patch. But current implementation doesn't meet this comment. There isn't any pfn walkers to take the lock so this looks like a relict from the past. This patch also removes this comment. [richard.weiyang@gmail.com: v4] Link: http://lkml.kernel.org/r/20181204085657.20472-1-richard.weiyang@gmail.com [mhocko@suse.com: changelog suggestion] Link: http://lkml.kernel.org/r/20181128091243.19249-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
23b68cfa |
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28-Dec-2018 |
Wei Yang <richard.weiyang@gmail.com> |
mm: check nr_initialised with PAGES_PER_SECTION directly in defer_init() When DEFERRED_STRUCT_PAGE_INIT is configured, only the first section of each node's highest zone is initialized before defer stage. static_init_pgcnt is used to store the number of pages like this: pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION, pgdat->node_spanned_pages); because we don't want to overflow zone's range. But this is not necessary, since defer_init() is called like this: memmap_init_zone() for pfn in [start_pfn, end_pfn) defer_init(pfn, end_pfn) In case (pgdat->node_spanned_pages < PAGES_PER_SECTION), the loop would stop before calling defer_init(). BTW, comparing PAGES_PER_SECTION with node_spanned_pages is not correct, since nr_initialised is zone based instead of node based. Even node_spanned_pages is bigger than PAGES_PER_SECTION, its highest zone would have pages less than PAGES_PER_SECTION. Link: http://lkml.kernel.org/r/20181122094807.6985-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: Pavel Tatashin <pasha.tatashin@oracle.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
c999fbd3 |
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28-Dec-2018 |
Alexey Dobriyan <adobriyan@gmail.com> |
mm/mmzone.c: make "migratetype_names" const char * Those strings are immutable in fact. Link: http://lkml.kernel.org/r/20181124090327.GA10877@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
1c30844d |
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28-Dec-2018 |
Mel Gorman <mgorman@techsingularity.net> |
mm: reclaim small amounts of memory when an external fragmentation event occurs An external fragmentation event was previously described as When the page allocator fragments memory, it records the event using the mm_page_alloc_extfrag event. If the fallback_order is smaller than a pageblock order (order-9 on 64-bit x86) then it's considered an event that will cause external fragmentation issues in the future. The kernel reduces the probability of such events by increasing the watermark sizes by calling set_recommended_min_free_kbytes early in the lifetime of the system. This works reasonably well in general but if there are enough sparsely populated pageblocks then the problem can still occur as enough memory is free overall and kswapd stays asleep. This patch introduces a watermark_boost_factor sysctl that allows a zone watermark to be temporarily boosted when an external fragmentation causing events occurs. The boosting will stall allocations that would decrease free memory below the boosted low watermark and kswapd is woken if the calling context allows to reclaim an amount of memory relative to the size of the high watermark and the watermark_boost_factor until the boost is cleared. When kswapd finishes, it wakes kcompactd at the pageblock order to clean some of the pageblocks that may have been affected by the fragmentation event. kswapd avoids any writeback, slab shrinkage and swap from reclaim context during this operation to avoid excessive system disruption in the name of fragmentation avoidance. Care is taken so that kswapd will do normal reclaim work if the system is really low on memory. This was evaluated using the same workloads as "mm, page_alloc: Spread allocations across zones before introducing fragmentation". 1-socket Skylake machine config-global-dhp__workload_thpfioscale XFS (no special madvise) 4 fio threads, 1 THP allocating thread -------------------------------------- 4.20-rc3 extfrag events < order 9: 804694 4.20-rc3+patch: 408912 (49% reduction) 4.20-rc3+patch1-4: 18421 (98% reduction) 4.20.0-rc3 4.20.0-rc3 lowzone-v5r8 boost-v5r8 Amean fault-base-1 653.58 ( 0.00%) 652.71 ( 0.13%) Amean fault-huge-1 0.00 ( 0.00%) 178.93 * -99.00%* 4.20.0-rc3 4.20.0-rc3 lowzone-v5r8 boost-v5r8 Percentage huge-1 0.00 ( 0.00%) 5.12 ( 100.00%) Note that external fragmentation causing events are massively reduced by this path whether in comparison to the previous kernel or the vanilla kernel. The fault latency for huge pages appears to be increased but that is only because THP allocations were successful with the patch applied. 1-socket Skylake machine global-dhp__workload_thpfioscale-madvhugepage-xfs (MADV_HUGEPAGE) ----------------------------------------------------------------- 4.20-rc3 extfrag events < order 9: 291392 4.20-rc3+patch: 191187 (34% reduction) 4.20-rc3+patch1-4: 13464 (95% reduction) thpfioscale Fault Latencies 4.20.0-rc3 4.20.0-rc3 lowzone-v5r8 boost-v5r8 Min fault-base-1 912.00 ( 0.00%) 905.00 ( 0.77%) Min fault-huge-1 127.00 ( 0.00%) 135.00 ( -6.30%) Amean fault-base-1 1467.55 ( 0.00%) 1481.67 ( -0.96%) Amean fault-huge-1 1127.11 ( 0.00%) 1063.88 * 5.61%* 4.20.0-rc3 4.20.0-rc3 lowzone-v5r8 boost-v5r8 Percentage huge-1 77.64 ( 0.00%) 83.46 ( 7.49%) As before, massive reduction in external fragmentation events, some jitter on latencies and an increase in THP allocation success rates. 2-socket Haswell machine config-global-dhp__workload_thpfioscale XFS (no special madvise) 4 fio threads, 5 THP allocating threads ---------------------------------------------------------------- 4.20-rc3 extfrag events < order 9: 215698 4.20-rc3+patch: 200210 (7% reduction) 4.20-rc3+patch1-4: 14263 (93% reduction) 4.20.0-rc3 4.20.0-rc3 lowzone-v5r8 boost-v5r8 Amean fault-base-5 1346.45 ( 0.00%) 1306.87 ( 2.94%) Amean fault-huge-5 3418.60 ( 0.00%) 1348.94 ( 60.54%) 4.20.0-rc3 4.20.0-rc3 lowzone-v5r8 boost-v5r8 Percentage huge-5 0.78 ( 0.00%) 7.91 ( 910.64%) There is a 93% reduction in fragmentation causing events, there is a big reduction in the huge page fault latency and allocation success rate is higher. 2-socket Haswell machine global-dhp__workload_thpfioscale-madvhugepage-xfs (MADV_HUGEPAGE) ----------------------------------------------------------------- 4.20-rc3 extfrag events < order 9: 166352 4.20-rc3+patch: 147463 (11% reduction) 4.20-rc3+patch1-4: 11095 (93% reduction) thpfioscale Fault Latencies 4.20.0-rc3 4.20.0-rc3 lowzone-v5r8 boost-v5r8 Amean fault-base-5 6217.43 ( 0.00%) 7419.67 * -19.34%* Amean fault-huge-5 3163.33 ( 0.00%) 3263.80 ( -3.18%) 4.20.0-rc3 4.20.0-rc3 lowzone-v5r8 boost-v5r8 Percentage huge-5 95.14 ( 0.00%) 87.98 ( -7.53%) There is a large reduction in fragmentation events with some jitter around the latencies and success rates. As before, the high THP allocation success rate does mean the system is under a lot of pressure. However, as the fragmentation events are reduced, it would be expected that the long-term allocation success rate would be higher. Link: http://lkml.kernel.org/r/20181123114528.28802-5-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a9214443 |
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28-Dec-2018 |
Mel Gorman <mgorman@techsingularity.net> |
mm: move zone watermark accesses behind an accessor This is a preparation patch only, no functional change. Link: http://lkml.kernel.org/r/20181123114528.28802-3-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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476567e8 |
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28-Dec-2018 |
Arun KS <arunks@codeaurora.org> |
mm: remove managed_page_count_lock spinlock Now that totalram_pages and managed_pages are atomic varibles, no need of managed_page_count spinlock. The lock had really a weak consistency guarantee. It hasn't been used for anything but the update but no reader actually cares about all the values being updated to be in sync. Link: http://lkml.kernel.org/r/1542090790-21750-5-git-send-email-arunks@codeaurora.org Signed-off-by: Arun KS <arunks@codeaurora.org> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
9705bea5 |
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28-Dec-2018 |
Arun KS <arunks@codeaurora.org> |
mm: convert zone->managed_pages to atomic variable totalram_pages, zone->managed_pages and totalhigh_pages updates are protected by managed_page_count_lock, but readers never care about it. Convert these variables to atomic to avoid readers potentially seeing a store tear. This patch converts zone->managed_pages. Subsequent patches will convert totalram_panges, totalhigh_pages and eventually managed_page_count_lock will be removed. Main motivation was that managed_page_count_lock handling was complicating things. It was discussed in length here, https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes better to remove the lock and convert variables to atomic, with preventing poteintial store-to-read tearing as a bonus. Link: http://lkml.kernel.org/r/1542090790-21750-3-git-send-email-arunks@codeaurora.org Signed-off-by: Arun KS <arunks@codeaurora.org> Suggested-by: Michal Hocko <mhocko@suse.com> Suggested-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
25078dc1 |
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16-Dec-2018 |
Christoph Hellwig <hch@lst.de> |
powerpc: use mm zones more sensibly Powerpc has somewhat odd usage where ZONE_DMA is used for all memory on common 64-bit configfs, and ZONE_DMA32 is used for 31-bit schemes. Move to a scheme closer to what other architectures use (and I dare to say the intent of the system): - ZONE_DMA: optionally for memory < 31-bit (64-bit embedded only) - ZONE_NORMAL: everything addressable by the kernel - ZONE_HIGHMEM: memory > 32-bit for 32-bit kernels Also provide information on how ZONE_DMA is used by defining ARCH_ZONE_DMA_BITS. Contains various fixes from Benjamin Herrenschmidt. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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9def36e0 |
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14-Dec-2018 |
Logan Gunthorpe <logang@deltatee.com> |
mm/sparse: add common helper to mark all memblocks present Presently the arches arm64, arm and sh have a function which loops through each memblock and calls memory present. riscv will require a similar function. Introduce a common memblocks_present() function that can be used by all the arches. Subsequent patches will cleanup the arches that make use of this. Link: http://lkml.kernel.org/r/20181107205433.3875-3-logang@deltatee.com Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
b4a991ec |
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30-Oct-2018 |
Mike Rapoport <rppt@linux.vnet.ibm.com> |
mm: remove CONFIG_NO_BOOTMEM All achitectures select NO_BOOTMEM which essentially becomes 'Y' for any kernel configuration and therefore it can be removed. [alexander.h.duyck@linux.intel.com: remove now defunct NO_BOOTMEM from depends list for deferred init] Link: http://lkml.kernel.org/r/20180925201814.3576.15105.stgit@localhost.localdomain Link: http://lkml.kernel.org/r/1536927045-23536-3-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Ingo Molnar <mingo@redhat.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Jonas Bonn <jonas@southpole.se> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ley Foon Tan <lftan@altera.com> Cc: Mark Salter <msalter@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Serge Semin <fancer.lancer@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
68d48e6a |
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26-Oct-2018 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: workingset: add vmstat counter for shadow nodes Make it easier to catch bugs in the shadow node shrinker by adding a counter for the shadow nodes in circulation. [akpm@linux-foundation.org: assert that irqs are disabled, for __inc_lruvec_page_state()] [akpm@linux-foundation.org: s/WARN_ON_ONCE/VM_WARN_ON_ONCE/, per Johannes] Link: http://lkml.kernel.org/r/20181009184732.762-4-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
1899ad18 |
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26-Oct-2018 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: workingset: tell cache transitions from workingset thrashing Refaults happen during transitions between workingsets as well as in-place thrashing. Knowing the difference between the two has a range of applications, including measuring the impact of memory shortage on the system performance, as well as the ability to smarter balance pressure between the filesystem cache and the swap-backed workingset. During workingset transitions, inactive cache refaults and pushes out established active cache. When that active cache isn't stale, however, and also ends up refaulting, that's bonafide thrashing. Introduce a new page flag that tells on eviction whether the page has been active or not in its lifetime. This bit is then stored in the shadow entry, to classify refaults as transitioning or thrashing. How many page->flags does this leave us with on 32-bit? 20 bits are always page flags 21 if you have an MMU 23 with the zone bits for DMA, Normal, HighMem, Movable 29 with the sparsemem section bits 30 if PAE is enabled 31 with this patch. So on 32-bit PAE, that leaves 1 bit for distinguishing two NUMA nodes. If that's not enough, the system can switch to discontigmem and re-gain the 6 or 7 sparsemem section bits. Link: http://lkml.kernel.org/r/20180828172258.3185-3-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Daniel Drake <drake@endlessm.com> Tested-by: Suren Baghdasaryan <surenb@google.com> Cc: Christopher Lameter <cl@linux.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Weiner <jweiner@fb.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Enderborg <peter.enderborg@sony.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vinayak Menon <vinmenon@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
b29940c1 |
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26-Oct-2018 |
Vlastimil Babka <vbabka@suse.cz> |
mm: rename and change semantics of nr_indirectly_reclaimable_bytes The vmstat counter NR_INDIRECTLY_RECLAIMABLE_BYTES was introduced by commit eb59254608bc ("mm: introduce NR_INDIRECTLY_RECLAIMABLE_BYTES") with the goal of accounting objects that can be reclaimed, but cannot be allocated via a SLAB_RECLAIM_ACCOUNT cache. This is now possible via kmalloc() with __GFP_RECLAIMABLE flag, and the dcache external names user is converted. The counter is however still useful for accounting direct page allocations (i.e. not slab) with a shrinker, such as the ION page pool. So keep it, and: - change granularity to pages to be more like other counters; sub-page allocations should be able to use kmalloc - rename the counter to NR_KERNEL_MISC_RECLAIMABLE - expose the counter again in vmstat as "nr_kernel_misc_reclaimable"; we can again remove the check for not printing "hidden" counters Link: http://lkml.kernel.org/r/20180731090649.16028-5-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Christoph Lameter <cl@linux.com> Acked-by: Roman Gushchin <guro@fb.com> Cc: Vijayanand Jitta <vjitta@codeaurora.org> Cc: Laura Abbott <labbott@redhat.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
e0546375 |
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06-Oct-2018 |
Srikar Dronamraju <srikar@linux.vnet.ibm.com> |
mm, sched/numa: Remove remaining traces of NUMA rate-limiting Remove the leftover pglist_data::numabalancing_migrate_lock and its initialization, we stopped using this lock with: efaffc5e40ae ("mm, sched/numa: Remove rate-limiting of automatic NUMA balancing migration") [ mingo: Rewrote the changelog. ] Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Linux-MM <linux-mm@kvack.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1538824999-31230-1-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
efaffc5e |
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01-Oct-2018 |
Mel Gorman <mgorman@techsingularity.net> |
mm, sched/numa: Remove rate-limiting of automatic NUMA balancing migration Rate limiting of page migrations due to automatic NUMA balancing was introduced to mitigate the worst-case scenario of migrating at high frequency due to false sharing or slowly ping-ponging between nodes. Since then, a lot of effort was spent on correctly identifying these pages and avoiding unnecessary migrations and the safety net may no longer be required. Jirka Hladky reported a regression in 4.17 due to a scheduler patch that avoids spreading STREAM tasks wide prematurely. However, once the task was properly placed, it delayed migrating the memory due to rate limiting. Increasing the limit fixed the problem for him. Currently, the limit is hard-coded and does not account for the real capabilities of the hardware. Even if an estimate was attempted, it would not properly account for the number of memory controllers and it could not account for the amount of bandwidth used for normal accesses. Rather than fudging, this patch simply eliminates the rate limiting. However, Jirka reports that a STREAM configuration using multiple processes achieved similar performance to 4.16. In local tests, this patch improved performance of STREAM relative to the baseline but it is somewhat machine-dependent. Most workloads show little or not performance difference implying that there is not a heavily reliance on the throttling mechanism and it is safe to remove. STREAM on 2-socket machine 4.19.0-rc5 4.19.0-rc5 numab-v1r1 noratelimit-v1r1 MB/sec copy 43298.52 ( 0.00%) 44673.38 ( 3.18%) MB/sec scale 30115.06 ( 0.00%) 31293.06 ( 3.91%) MB/sec add 32825.12 ( 0.00%) 34883.62 ( 6.27%) MB/sec triad 32549.52 ( 0.00%) 34906.60 ( 7.24% Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Rik van Riel <riel@surriel.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Jirka Hladky <jhladky@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Linux-MM <linux-mm@kvack.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20181001100525.29789-2-mgorman@techsingularity.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
c1093b74 |
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21-Aug-2018 |
Pavel Tatashin <pasha.tatashin@oracle.com> |
mm: access zone->node via zone_to_nid() and zone_set_nid() zone->node is configured only when CONFIG_NUMA=y, so it is a good idea to have inline functions to access this field in order to avoid ifdef's in c files. Link: http://lkml.kernel.org/r/20180730101757.28058-3-osalvador@techadventures.net Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Signed-off-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Aaron Lu <aaron.lu@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
89696701 |
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21-Aug-2018 |
Oscar Salvador <osalvador@suse.de> |
mm: remove zone_id() and make use of zone_idx() in is_dev_zone() is_dev_zone() is using zone_id() to check if the zone is ZONE_DEVICE. zone_id() looks pretty much the same as zone_idx(), and while the use of zone_idx() is quite spread in the kernel, zone_id() is only being used by is_dev_zone(). This patch removes zone_id() and makes is_dev_zone() use zone_idx() to check the zone, so we do not have two things with the same functionality around. Link: http://lkml.kernel.org/r/20180730133718.28683-1-osalvador@techadventures.net Signed-off-by: Oscar Salvador <osalvador@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com> Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
d3cda233 |
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10-Apr-2018 |
Joonsoo Kim <iamjoonsoo.kim@lge.com> |
mm/page_alloc: don't reserve ZONE_HIGHMEM for ZONE_MOVABLE request Freepage on ZONE_HIGHMEM doesn't work for kernel memory so it's not that important to reserve. When ZONE_MOVABLE is used, this problem would theorectically cause to decrease usable memory for GFP_HIGHUSER_MOVABLE allocation request which is mainly used for page cache and anon page allocation. So, fix it by setting 0 to sysctl_lowmem_reserve_ratio[ZONE_HIGHMEM]. And, defining sysctl_lowmem_reserve_ratio array by MAX_NR_ZONES - 1 size makes code complex. For example, if there is highmem system, following reserve ratio is activated for *NORMAL ZONE* which would be easyily misleading people. #ifdef CONFIG_HIGHMEM 32 #endif This patch also fixes this situation by defining sysctl_lowmem_reserve_ratio array by MAX_NR_ZONES and place "#ifdef" to right place. Link: http://lkml.kernel.org/r/1504672525-17915-1-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Tony Lindgren <tony@atomide.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Will Deacon <will.deacon@arm.com> Cc: <linux-api@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
eb592546 |
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10-Apr-2018 |
Roman Gushchin <guro@fb.com> |
mm: introduce NR_INDIRECTLY_RECLAIMABLE_BYTES Patch series "indirectly reclaimable memory", v2. This patchset introduces the concept of indirectly reclaimable memory and applies it to fix the issue of when a big number of dentries with external names can significantly affect the MemAvailable value. This patch (of 3): Introduce a concept of indirectly reclaimable memory and adds the corresponding memory counter and /proc/vmstat item. Indirectly reclaimable memory is any sort of memory, used by the kernel (except of reclaimable slabs), which is actually reclaimable, i.e. will be released under memory pressure. The counter is in bytes, as it's not always possible to count such objects in pages. The name contains BYTES by analogy to NR_KERNEL_STACK_KB. Link: http://lkml.kernel.org/r/20180305133743.12746-2-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
5ecd9d40 |
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05-Apr-2018 |
David Rientjes <rientjes@google.com> |
mm, page_alloc: wakeup kcompactd even if kswapd cannot free more memory Kswapd will not wakeup if per-zone watermarks are not failing or if too many previous attempts at background reclaim have failed. This can be true if there is a lot of free memory available. For high- order allocations, kswapd is responsible for waking up kcompactd for background compaction. If the zone is not below its watermarks or reclaim has recently failed (lots of free memory, nothing left to reclaim), kcompactd does not get woken up. When __GFP_DIRECT_RECLAIM is not allowed, allow kcompactd to still be woken up even if kswapd will not reclaim. This allows high-order allocations, such as thp, to still trigger background compaction even when the zone has an abundance of free memory. Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803111659420.209721@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
3a2d7fa8 |
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05-Apr-2018 |
Pavel Tatashin <pasha.tatashin@oracle.com> |
mm: disable interrupts while initializing deferred pages Vlastimil Babka reported about a window issue during which when deferred pages are initialized, and the current version of on-demand initialization is finished, allocations may fail. While this is highly unlikely scenario, since this kind of allocation request must be large, and must come from interrupt handler, we still want to cover it. We solve this by initializing deferred pages with interrupts disabled, and holding node_size_lock spin lock while pages in the node are being initialized. The on-demand deferred page initialization that comes later will use the same lock, and thus synchronize with deferred_init_memmap(). It is unlikely for threads that initialize deferred pages to be interrupted. They run soon after smp_init(), but before modules are initialized, and long before user space programs. This is why there is no adverse effect of having these threads running with interrupts disabled. [pasha.tatashin@oracle.com: v6] Link: http://lkml.kernel.org/r/20180313182355.17669-2-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180309220807.24961-2-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Gioh Kim <gi-oh.kim@profitbricks.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Miles Chen <miles.chen@mediatek.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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fc5d1073 |
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27-Mar-2018 |
David Rientjes <rientjes@google.com> |
x86/mm/32: Remove unused node_memmap_size_bytes() & CONFIG_NEED_NODE_MEMMAP_SIZE logic node_memmap_size_bytes() has been unused since the v3.9 kernel, so remove it. Signed-off-by: David Rientjes <rientjes@google.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Laura Abbott <labbott@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Fixes: f03574f2d5b2 ("x86-32, mm: Rip out x86_32 NUMA remapping code") Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803262325540.256524@chino.kir.corp.google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
def9b71e |
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31-Jan-2018 |
Petr Tesarik <ptesarik@suse.com> |
include/linux/mmzone.h: fix explanation of lower bits in the SPARSEMEM mem_map pointer The comment is confusing. On the one hand, it refers to 32-bit alignment (struct page alignment on 32-bit platforms), but this would only guarantee that the 2 lowest bits must be zero. On the other hand, it claims that at least 3 bits are available, and 3 bits are actually used. This is not broken, because there is a stronger alignment guarantee, just less obvious. Let's fix the comment to make it clear how many bits are available and why. Although memmap arrays are allocated in various places, the resulting pointer is encoded eventually, so I am adding a BUG_ON() here to enforce at runtime that all expected bits are indeed available. I have also added a BUILD_BUG_ON to check that PFN_SECTION_SHIFT is sufficient, because this part of the calculation can be easily checked at build time. [ptesarik@suse.com: v2] Link: http://lkml.kernel.org/r/20180125100516.589ea6af@ezekiel.suse.cz Link: http://lkml.kernel.org/r/20180119080908.3a662e6f@ezekiel.suse.cz Signed-off-by: Petr Tesarik <ptesarik@suse.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kemi Wang <kemi.wang@intel.com> Cc: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d135e575 |
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15-Nov-2017 |
Pavel Tatashin <pasha.tatashin@oracle.com> |
mm/page_alloc.c: broken deferred calculation In reset_deferred_meminit() we determine number of pages that must not be deferred. We initialize pages for at least 2G of memory, but also pages for reserved memory in this node. The reserved memory is determined in this function: memblock_reserved_memory_within(), which operates over physical addresses, and returns size in bytes. However, reset_deferred_meminit() assumes that that this function operates with pfns, and returns page count. The result is that in the best case machine boots slower than expected due to initializing more pages than needed in single thread, and in the worst case panics because fewer than needed pages are initialized early. Link: http://lkml.kernel.org/r/20171021011707.15191-1-pasha.tatashin@oracle.com Fixes: 864b9a393dcb ("mm: consider memblock reservations for deferred memory initialization sizing") Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
3a50d14d |
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15-Nov-2017 |
Andrey Ryabinin <ryabinin.a.a@gmail.com> |
mm: remove unused pgdat->inactive_ratio Since commit 59dc76b0d4df ("mm: vmscan: reduce size of inactive file list") 'pgdat->inactive_ratio' is not used, except for printing "node_inactive_ratio: 0" in /proc/zoneinfo output. Remove it. Link: http://lkml.kernel.org/r/20171003152611.27483-1-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
b2441318 |
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01-Nov-2017 |
Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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83e3c487 |
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29-Sep-2017 |
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> |
mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y Size of the mem_section[] array depends on the size of the physical address space. In preparation for boot-time switching between paging modes on x86-64 we need to make the allocation of mem_section[] dynamic, because otherwise we waste a lot of RAM: with CONFIG_NODE_SHIFT=10, mem_section[] size is 32kB for 4-level paging and 2MB for 5-level paging mode. The patch allocates the array on the first call to sparse_memory_present_with_active_regions(). Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@suse.de> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20170929140821.37654-2-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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1dd2bfc8 |
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03-Oct-2017 |
YASUAKI ISHIMATSU <yasu.isimatu@gmail.com> |
mm/memory_hotplug: change pfn_to_section_nr/section_nr_to_pfn macro to inline function pfn_to_section_nr() and section_nr_to_pfn() are defined as macro. pfn_to_section_nr() has no issue even if it is defined as macro. But section_nr_to_pfn() has overflow issue if sec is defined as int. section_nr_to_pfn() just shifts sec by PFN_SECTION_SHIFT. If sec is defined as unsigned long, section_nr_to_pfn() returns pfn as 64 bit value. But if sec is defined as int, section_nr_to_pfn() returns pfn as 32 bit value. __remove_section() calculates start_pfn using section_nr_to_pfn() and scn_nr defined as int. So if hot-removed memory address is over 16TB, overflow issue occurs and section_nr_to_pfn() does not calculate correct pfn. To make callers use proper arg, the patch changes the macros to inline functions. Fixes: 815121d2b5cd ("memory_hotplug: clear zone when removing the memory") Link: http://lkml.kernel.org/r/e643a387-e573-6bbf-d418-c60c8ee3d15e@gmail.com Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: Reza Arbab <arbab@linux.vnet.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1d90ca89 |
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08-Sep-2017 |
Kemi Wang <kemi.wang@intel.com> |
mm: update NUMA counter threshold size There is significant overhead in cache bouncing caused by zone counters (NUMA associated counters) update in parallel in multi-threaded page allocation (suggested by Dave Hansen). This patch updates NUMA counter threshold to a fixed size of MAX_U16 - 2, as a small threshold greatly increases the update frequency of the global counter from local per cpu counter(suggested by Ying Huang). The rationality is that these statistics counters don't affect the kernel's decision, unlike other VM counters, so it's not a problem to use a large threshold. With this patchset, we see 31.3% drop of CPU cycles(537-->369) for per single page allocation and reclaim on Jesper's page_bench03 benchmark. Benchmark provided by Jesper D Brouer(increase loop times to 10000000): https://github.com/netoptimizer/prototype-kernel/tree/master/kernel/mm/ bench Threshold CPU cycles Throughput(88 threads) 32 799 241760478 64 640 301628829 125 537 358906028 <==> system by default (base) 256 468 412397590 512 428 450550704 4096 399 482520943 20000 394 489009617 30000 395 488017817 65533 369(-31.3%) 521661345(+45.3%) <==> with this patchset N/A 342(-36.3%) 562900157(+56.8%) <==> disable zone_statistics Link: http://lkml.kernel.org/r/1503568801-21305-3-git-send-email-kemi.wang@intel.com Signed-off-by: Kemi Wang <kemi.wang@intel.com> Reported-by: Jesper Dangaard Brouer <brouer@redhat.com> Suggested-by: Dave Hansen <dave.hansen@intel.com> Suggested-by: Ying Huang <ying.huang@intel.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Aaron Lu <aaron.lu@intel.com> Cc: Andi Kleen <andi.kleen@intel.com> Cc: Christopher Lameter <cl@linux.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Tim Chen <tim.c.chen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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3a321d2a |
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08-Sep-2017 |
Kemi Wang <kemi.wang@intel.com> |
mm: change the call sites of numa statistics items Patch series "Separate NUMA statistics from zone statistics", v2. Each page allocation updates a set of per-zone statistics with a call to zone_statistics(). As discussed in 2017 MM summit, these are a substantial source of overhead in the page allocator and are very rarely consumed. This significant overhead in cache bouncing caused by zone counters (NUMA associated counters) update in parallel in multi-threaded page allocation (pointed out by Dave Hansen). A link to the MM summit slides: http://people.netfilter.org/hawk/presentations/MM-summit2017/MM-summit2017-JesperBrouer.pdf To mitigate this overhead, this patchset separates NUMA statistics from zone statistics framework, and update NUMA counter threshold to a fixed size of MAX_U16 - 2, as a small threshold greatly increases the update frequency of the global counter from local per cpu counter (suggested by Ying Huang). The rationality is that these statistics counters don't need to be read often, unlike other VM counters, so it's not a problem to use a large threshold and make readers more expensive. With this patchset, we see 31.3% drop of CPU cycles(537-->369, see below) for per single page allocation and reclaim on Jesper's page_bench03 benchmark. Meanwhile, this patchset keeps the same style of virtual memory statistics with little end-user-visible effects (only move the numa stats to show behind zone page stats, see the first patch for details). I did an experiment of single page allocation and reclaim concurrently using Jesper's page_bench03 benchmark on a 2-Socket Broadwell-based server (88 processors with 126G memory) with different size of threshold of pcp counter. Benchmark provided by Jesper D Brouer(increase loop times to 10000000): https://github.com/netoptimizer/prototype-kernel/tree/master/kernel/mm/bench Threshold CPU cycles Throughput(88 threads) 32 799 241760478 64 640 301628829 125 537 358906028 <==> system by default 256 468 412397590 512 428 450550704 4096 399 482520943 20000 394 489009617 30000 395 488017817 65533 369(-31.3%) 521661345(+45.3%) <==> with this patchset N/A 342(-36.3%) 562900157(+56.8%) <==> disable zone_statistics This patch (of 3): In this patch, NUMA statistics is separated from zone statistics framework, all the call sites of NUMA stats are changed to use numa-stats-specific functions, it does not have any functionality change except that the number of NUMA stats is shown behind zone page stats when users *read* the zone info. E.g. cat /proc/zoneinfo ***Base*** ***With this patch*** nr_free_pages 3976 nr_free_pages 3976 nr_zone_inactive_anon 0 nr_zone_inactive_anon 0 nr_zone_active_anon 0 nr_zone_active_anon 0 nr_zone_inactive_file 0 nr_zone_inactive_file 0 nr_zone_active_file 0 nr_zone_active_file 0 nr_zone_unevictable 0 nr_zone_unevictable 0 nr_zone_write_pending 0 nr_zone_write_pending 0 nr_mlock 0 nr_mlock 0 nr_page_table_pages 0 nr_page_table_pages 0 nr_kernel_stack 0 nr_kernel_stack 0 nr_bounce 0 nr_bounce 0 nr_zspages 0 nr_zspages 0 numa_hit 0 *nr_free_cma 0* numa_miss 0 numa_hit 0 numa_foreign 0 numa_miss 0 numa_interleave 0 numa_foreign 0 numa_local 0 numa_interleave 0 numa_other 0 numa_local 0 *nr_free_cma 0* numa_other 0 ... ... vm stats threshold: 10 vm stats threshold: 10 ... ... The next patch updates the numa stats counter size and threshold. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/1503568801-21305-2-git-send-email-kemi.wang@intel.com Signed-off-by: Kemi Wang <kemi.wang@intel.com> Reported-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Christopher Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi.kleen@intel.com> Cc: Ying Huang <ying.huang@intel.com> Cc: Aaron Lu <aaron.lu@intel.com> Cc: Tim Chen <tim.c.chen@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b93e0f32 |
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06-Sep-2017 |
Michal Hocko <mhocko@suse.com> |
mm, memory_hotplug: get rid of zonelists_mutex zonelists_mutex was introduced by commit 4eaf3f64397c ("mem-hotplug: fix potential race while building zonelist for new populated zone") to protect zonelist building from races. This is no longer needed though because both memory online and offline are fully serialized. New users have grown since then. Notably setup_per_zone_wmarks wants to prevent from races between memory hotplug, khugepaged setup and manual min_free_kbytes update via sysctl (see cfd3da1e49bb ("mm: Serialize access to min_free_kbytes"). Let's add a private lock for that purpose. This will not prevent from seeing halfway through memory hotplug operation but that shouldn't be a big deal becuse memory hotplug will update watermarks explicitly so we will eventually get a full picture. The lock just makes sure we won't race when updating watermarks leading to weird results. Also __build_all_zonelists manipulates global data so add a private lock for it as well. This doesn't seem to be necessary today but it is more robust to have a lock there. While we are at it make sure we document that memory online/offline depends on a full serialization either via mem_hotplug_begin() or device_lock. Link: http://lkml.kernel.org/r/20170721143915.14161-9-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Haicheng Li <haicheng.li@linux.intel.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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72675e13 |
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06-Sep-2017 |
Michal Hocko <mhocko@suse.com> |
mm, memory_hotplug: drop zone from build_all_zonelists build_all_zonelists gets a zone parameter to initialize zone's pagesets. There is only a single user which gives a non-NULL zone parameter and that one doesn't really need the rest of the build_all_zonelists (see commit 6dcd73d7011b ("memory-hotplug: allocate zone's pcp before onlining pages")). Therefore remove setup_zone_pageset from build_all_zonelists and call it from its only user directly. This will also remove a pointless zonlists rebuilding which is always good. Link: http://lkml.kernel.org/r/20170721143915.14161-5-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c9bff3ee |
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06-Sep-2017 |
Michal Hocko <mhocko@suse.com> |
mm, page_alloc: rip out ZONELIST_ORDER_ZONE Patch series "cleanup zonelists initialization", v1. This is aimed at cleaning up the zonelists initialization code we have but the primary motivation was bug report [2] which got resolved but the usage of stop_machine is just too ugly to live. Most patches are straightforward but 3 of them need a special consideration. Patch 1 removes zone ordered zonelists completely. I am CCing linux-api because this is a user visible change. As I argue in the patch description I do not think we have a strong usecase for it these days. I have kept sysctl in place and warn into the log if somebody tries to configure zone lists ordering. If somebody has a real usecase for it we can revert this patch but I do not expect anybody will actually notice runtime differences. This patch is not strictly needed for the rest but it made patch 6 easier to implement. Patch 7 removes stop_machine from build_all_zonelists without adding any special synchronization between iterators and updater which I _believe_ is acceptable as explained in the changelog. I hope I am not missing anything. Patch 8 then removes zonelists_mutex which is kind of ugly as well and not really needed AFAICS but a care should be taken when double checking my thinking. This patch (of 9): Supporting zone ordered zonelists costs us just a lot of code while the usefulness is arguable if existent at all. Mel has already made node ordering default on 64b systems. 32b systems are still using ZONELIST_ORDER_ZONE because it is considered better to fallback to a different NUMA node rather than consume precious lowmem zones. This argument is, however, weaken by the fact that the memory reclaim has been reworked to be node rather than zone oriented. This means that lowmem requests have to skip over all highmem pages on LRUs already and so zone ordering doesn't save the reclaim time much. So the only advantage of the zone ordering is under a light memory pressure when highmem requests do not ever hit into lowmem zones and the lowmem pressure doesn't need to reclaim. Considering that 32b NUMA systems are rather suboptimal already and it is generally advisable to use 64b kernel on such a HW I believe we should rather care about the code maintainability and just get rid of ZONELIST_ORDER_ZONE altogether. Keep systcl in place and warn if somebody tries to set zone ordering either from kernel command line or the sysctl. [mhocko@suse.com: reading vm.numa_zonelist_order will never terminate] Link: http://lkml.kernel.org/r/20170721143915.14161-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Cc: <linux-api@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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9d1f4b3f |
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10-Jul-2017 |
Michal Hocko <mhocko@suse.com> |
mm: disallow early_pfn_to_nid on configurations which do not implement it early_pfn_to_nid will return node 0 if both HAVE_ARCH_EARLY_PFN_TO_NID and HAVE_MEMBLOCK_NODE_MAP are disabled. It seems we are safe now because all architectures which support NUMA define one of them (with an exception of alpha which however has CONFIG_NUMA marked as broken) so this works as expected. It can get silently and subtly broken too easily, though. Make sure we fail the compilation if NUMA is enabled and there is no proper implementation for this function. If that ever happens we know that either the specific configuration is invalid and the fix should either disable NUMA or enable one of the above configs. Link: http://lkml.kernel.org/r/20170704075803.15979-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Yang Shi <yang.shi@linaro.org> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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618b8c20 |
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10-Jul-2017 |
Nikolay Borisov <nborisov@suse.com> |
include/linux/mmzone.h: remove ancient/ambiguous comment Currently pg_data_t is just a struct which describes a NUMA node memory layout. Let's keep the comment simple and remove ambiguity. Link: http://lkml.kernel.org/r/1498220534-22717-1-git-send-email-nborisov@suse.com Signed-off-by: Nikolay Borisov <nborisov@suse.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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385386cf |
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06-Jul-2017 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: vmstat: move slab statistics from zone to node counters Patch series "mm: per-lruvec slab stats" Josef is working on a new approach to balancing slab caches and the page cache. For this to work, he needs slab cache statistics on the lruvec level. These patches implement that by adding infrastructure that allows updating and reading generic VM stat items per lruvec, then switches some existing VM accounting sites, including the slab accounting ones, to this new cgroup-aware API. I'll follow up with more patches on this, because there is actually substantial simplification that can be done to the memory controller when we replace private memcg accounting with making the existing VM accounting sites cgroup-aware. But this is enough for Josef to base his slab reclaim work on, so here goes. This patch (of 5): To re-implement slab cache vs. page cache balancing, we'll need the slab counters at the lruvec level, which, ever since lru reclaim was moved from the zone to the node, is the intersection of the node, not the zone, and the memcg. We could retain the per-zone counters for when the page allocator dumps its memory information on failures, and have counters on both levels - which on all but NUMA node 0 is usually redundant. But let's keep it simple for now and just move them. If anybody complains we can restore the per-zone counters. [hannes@cmpxchg.org: fix oops] Link: http://lkml.kernel.org/r/20170605183511.GA8915@cmpxchg.org Link: http://lkml.kernel.org/r/20170530181724.27197-3-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f1dd2cd1 |
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06-Jul-2017 |
Michal Hocko <mhocko@suse.com> |
mm, memory_hotplug: do not associate hotadded memory to zones until online The current memory hotplug implementation relies on having all the struct pages associate with a zone/node during the physical hotplug phase (arch_add_memory->__add_pages->__add_section->__add_zone). In the vast majority of cases this means that they are added to ZONE_NORMAL. This has been so since 9d99aaa31f59 ("[PATCH] x86_64: Support memory hotadd without sparsemem") and it wasn't a big deal back then because movable onlining didn't exist yet. Much later memory hotplug wanted to (ab)use ZONE_MOVABLE for movable onlining 511c2aba8f07 ("mm, memory-hotplug: dynamic configure movable memory and portion memory") and then things got more complicated. Rather than reconsidering the zone association which was no longer needed (because the memory hotplug already depended on SPARSEMEM) a convoluted semantic of zone shifting has been developed. Only the currently last memblock or the one adjacent to the zone_movable can be onlined movable. This essentially means that the online type changes as the new memblocks are added. Let's simulate memory hot online manually $ echo 0x100000000 > /sys/devices/system/memory/probe $ grep . /sys/devices/system/memory/memory32/valid_zones Normal Movable $ echo $((0x100000000+(128<<20))) > /sys/devices/system/memory/probe $ grep . /sys/devices/system/memory/memory3?/valid_zones /sys/devices/system/memory/memory32/valid_zones:Normal /sys/devices/system/memory/memory33/valid_zones:Normal Movable $ echo $((0x100000000+2*(128<<20))) > /sys/devices/system/memory/probe $ grep . /sys/devices/system/memory/memory3?/valid_zones /sys/devices/system/memory/memory32/valid_zones:Normal /sys/devices/system/memory/memory33/valid_zones:Normal /sys/devices/system/memory/memory34/valid_zones:Normal Movable $ echo online_movable > /sys/devices/system/memory/memory34/state $ grep . /sys/devices/system/memory/memory3?/valid_zones /sys/devices/system/memory/memory32/valid_zones:Normal /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory34/valid_zones:Movable Normal This is an awkward semantic because an udev event is sent as soon as the block is onlined and an udev handler might want to online it based on some policy (e.g. association with a node) but it will inherently race with new blocks showing up. This patch changes the physical online phase to not associate pages with any zone at all. All the pages are just marked reserved and wait for the onlining phase to be associated with the zone as per the online request. There are only two requirements - existing ZONE_NORMAL and ZONE_MOVABLE cannot overlap - ZONE_NORMAL precedes ZONE_MOVABLE in physical addresses the latter one is not an inherent requirement and can be changed in the future. It preserves the current behavior and made the code slightly simpler. This is subject to change in future. This means that the same physical online steps as above will lead to the following state: Normal Movable /sys/devices/system/memory/memory32/valid_zones:Normal Movable /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory32/valid_zones:Normal Movable /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory34/valid_zones:Normal Movable /sys/devices/system/memory/memory32/valid_zones:Normal Movable /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory34/valid_zones:Movable Implementation: The current move_pfn_range is reimplemented to check the above requirements (allow_online_pfn_range) and then updates the respective zone (move_pfn_range_to_zone), the pgdat and links all the pages in the pfn range with the zone/node. __add_pages is updated to not require the zone and only initializes sections in the range. This allowed to simplify the arch_add_memory code (s390 could get rid of quite some of code). devm_memremap_pages is the only user of arch_add_memory which relies on the zone association because it only hooks into the memory hotplug only half way. It uses it to associate the new memory with ZONE_DEVICE but doesn't allow it to be {on,off}lined via sysfs. This means that this particular code path has to call move_pfn_range_to_zone explicitly. The original zone shifting code is kept in place and will be removed in the follow up patch for an easier review. Please note that this patch also changes the original behavior when offlining a memory block adjacent to another zone (Normal vs. Movable) used to allow to change its movable type. This will be handled later. [richard.weiyang@gmail.com: simplify zone_intersects()] Link: http://lkml.kernel.org/r/20170616092335.5177-1-richard.weiyang@gmail.com [richard.weiyang@gmail.com: remove duplicate call for set_page_links] Link: http://lkml.kernel.org/r/20170616092335.5177-2-richard.weiyang@gmail.com [akpm@linux-foundation.org: remove unused local `i'] Link: http://lkml.kernel.org/r/20170515085827.16474-12-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Tested-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Reza Arbab <arbab@linux.vnet.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # For s390 bits Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Daniel Kiper <daniel.kiper@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Tobias Regnery <tobias.regnery@gmail.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
2d070eab |
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06-Jul-2017 |
Michal Hocko <mhocko@suse.com> |
mm: consider zone which is not fully populated to have holes __pageblock_pfn_to_page has two users currently, set_zone_contiguous which checks whether the given zone contains holes and pageblock_pfn_to_page which then carefully returns a first valid page from the given pfn range for the given zone. This doesn't handle zones which are not fully populated though. Memory pageblocks can be offlined or might not have been onlined yet. In such a case the zone should be considered to have holes otherwise pfn walkers can touch and play with offline pages. Current callers of pageblock_pfn_to_page in compaction seem to work properly right now because they only isolate PageBuddy (isolate_freepages_block) or PageLRU resp. __PageMovable (isolate_migratepages_block) which will be always false for these pages. It would be safer to skip these pages altogether, though. In order to do this patch adds a new memory section state (SECTION_IS_ONLINE) which is set in memory_present (during boot time) or in online_pages_range during the memory hotplug. Similarly offline_mem_sections clears the bit and it is called when the memory range is offlined. pfn_to_online_page helper is then added which check the mem section and only returns a page if it is onlined already. Use the new helper in __pageblock_pfn_to_page and skip the whole page block in such a case. [mhocko@suse.com: check valid section number in pfn_to_online_page (Vlastimil), mark sections online after all struct pages are initialized in online_pages_range (Vlastimil)] Link: http://lkml.kernel.org/r/20170518164210.GD18333@dhcp22.suse.cz Link: http://lkml.kernel.org/r/20170515085827.16474-8-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Daniel Kiper <daniel.kiper@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Reza Arbab <arbab@linux.vnet.ibm.com> Cc: Tobias Regnery <tobias.regnery@gmail.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
dc0bbf3b |
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06-Jul-2017 |
Michal Hocko <mhocko@suse.com> |
mm: remove return value from init_currently_empty_zone Patch series "mm: make movable onlining suck less", v4. Movable onlining is a real hack with many downsides - mainly reintroduction of lowmem/highmem issues we used to have on 32b systems - but it is the only way to make the memory hotremove more reliable which is something that people are asking for. The current semantic of memory movable onlinening is really cumbersome, however. The main reason for this is that the udev driven approach is basically unusable because udev races with the memory probing while only the last memory block or the one adjacent to the existing zone_movable are allowed to be onlined movable. In short the criterion for the successful online_movable changes under udev's feet. A reliable udev approach would require a 2 phase approach where the first successful movable online would have to check all the previous blocks and online them in descending order. This is hard to be considered sane. This patchset aims at making the onlining semantic more usable. First of all it allows to online memory movable as long as it doesn't clash with the existing ZONE_NORMAL. That means that ZONE_NORMAL and ZONE_MOVABLE cannot overlap. Currently I preserve the original ordering semantic so the zone always precedes the movable zone but I have plans to remove this restriction in future because it is not really necessary. First 3 patches are cleanups which should be ready to be merged right away (unless I have missed something subtle of course). Patch 4 deals with ZONE_DEVICE dependencies down the __add_pages path. Patch 5 deals with implicit assumptions of register_one_node on pgdat initialization. Patches 6-10 deal with offline holes in the zone for pfn walkers. I hope I got all of them right but people familiar with compaction should double check this. Patch 11 is the core of the change. In order to make it easier to review I have tried it to be as minimalistic as possible and the large code removal is moved to patch 14. Patch 12 is a trivial follow up cleanup. Patch 13 fixes sparse warnings and finally patch 14 removes the unused code. I have tested the patches in kvm: # qemu-system-x86_64 -enable-kvm -monitor pty -m 2G,slots=4,maxmem=4G -numa node,mem=1G -numa node,mem=1G ... and then probed the additional memory by (qemu) object_add memory-backend-ram,id=mem1,size=1G (qemu) device_add pc-dimm,id=dimm1,memdev=mem1 Then I have used this simple script to probe the memory block by hand # cat probe_memblock.sh #!/bin/sh BLOCK_NR=$1 # echo $((0x100000000+$BLOCK_NR*(128<<20))) > /sys/devices/system/memory/probe # for i in $(seq 10); do sh probe_memblock.sh $i; done # grep . /sys/devices/system/memory/memory3?/valid_zones 2>/dev/null /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory34/valid_zones:Normal Movable /sys/devices/system/memory/memory35/valid_zones:Normal Movable /sys/devices/system/memory/memory36/valid_zones:Normal Movable /sys/devices/system/memory/memory37/valid_zones:Normal Movable /sys/devices/system/memory/memory38/valid_zones:Normal Movable /sys/devices/system/memory/memory39/valid_zones:Normal Movable The main difference to the original implementation is that all new memblocks can be both online_kernel and online_movable initially because there is no clash obviously. For the comparison the original implementation would have /sys/devices/system/memory/memory33/valid_zones:Normal /sys/devices/system/memory/memory34/valid_zones:Normal /sys/devices/system/memory/memory35/valid_zones:Normal /sys/devices/system/memory/memory36/valid_zones:Normal /sys/devices/system/memory/memory37/valid_zones:Normal /sys/devices/system/memory/memory38/valid_zones:Normal /sys/devices/system/memory/memory39/valid_zones:Normal Movable Now # echo online_movable > /sys/devices/system/memory/memory34/state # grep . /sys/devices/system/memory/memory3?/valid_zones 2>/dev/null /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory34/valid_zones:Movable /sys/devices/system/memory/memory35/valid_zones:Movable /sys/devices/system/memory/memory36/valid_zones:Movable /sys/devices/system/memory/memory37/valid_zones:Movable /sys/devices/system/memory/memory38/valid_zones:Movable /sys/devices/system/memory/memory39/valid_zones:Movable Block 33 can still be online both kernel and movable while all the remaining can be only movable. /proc/zonelist says Node 0, zone Normal pages free 0 min 0 low 0 high 0 spanned 0 present 0 -- Node 0, zone Movable pages free 32753 min 85 low 117 high 149 spanned 32768 present 32768 A new memblock at a lower address will result in a new memblock (32) which will still allow both Normal and Movable. # sh probe_memblock.sh 0 # grep . /sys/devices/system/memory/memory3[2-5]/valid_zones 2>/dev/null /sys/devices/system/memory/memory32/valid_zones:Normal Movable /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory34/valid_zones:Movable /sys/devices/system/memory/memory35/valid_zones:Movable and online_kernel will convert it to the zone normal properly while 33 can be still onlined both ways. # echo online_kernel > /sys/devices/system/memory/memory32/state # grep . /sys/devices/system/memory/memory3[2-5]/valid_zones 2>/dev/null /sys/devices/system/memory/memory32/valid_zones:Normal /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory34/valid_zones:Movable /sys/devices/system/memory/memory35/valid_zones:Movable /proc/zoneinfo will now tell Node 0, zone Normal pages free 65441 min 165 low 230 high 295 spanned 65536 present 65536 -- Node 0, zone Movable pages free 32740 min 82 low 114 high 146 spanned 32768 present 32768 so both zones have one memblock spanned and present. Onlining 39 should associate this block to the movable zone # echo online > /sys/devices/system/memory/memory39/state /proc/zoneinfo will now tell Node 0, zone Normal pages free 32765 min 80 low 112 high 144 spanned 32768 present 32768 -- Node 0, zone Movable pages free 65501 min 160 low 225 high 290 spanned 196608 present 65536 so we will have a movable zone which spans 6 memblocks, 2 present and 4 representing a hole. Offlining both movable blocks will lead to the zone with no present pages which is the expected behavior I believe. # echo offline > /sys/devices/system/memory/memory39/state # echo offline > /sys/devices/system/memory/memory34/state # grep -A6 "Movable\|Normal" /proc/zoneinfo Node 0, zone Normal pages free 32735 min 90 low 122 high 154 spanned 32768 present 32768 -- Node 0, zone Movable pages free 0 min 0 low 0 high 0 spanned 196608 present 0 As a bonus we will get a nice cleanup in the memory hotplug codebase. This patch (of 16): init_currently_empty_zone doesn't have any error to return yet it is still an int and callers try to be defensive and try to handle potential error. Remove this nonsense and simplify all callers. This patch shouldn't have any visible effect Link: http://lkml.kernel.org/r/20170515085827.16474-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Acked-by: Balbir Singh <bsingharora@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Daniel Kiper <daniel.kiper@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Reza Arbab <arbab@linux.vnet.ibm.com> Cc: Tobias Regnery <tobias.regnery@gmail.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c4e1be9e |
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06-Jul-2017 |
Dave Hansen <dave.hansen@linux.intel.com> |
mm, sparsemem: break out of loops early There are a number of times that we loop over NR_MEM_SECTIONS, looking for section_present() on each section. But, when we have very large physical address spaces (large MAX_PHYSMEM_BITS), NR_MEM_SECTIONS becomes very large, making the loops quite long. With MAX_PHYSMEM_BITS=46 and a section size of 128MB, the current loops are 512k iterations, which we barely notice on modern hardware. But, raising MAX_PHYSMEM_BITS higher (like we will see on systems that support 5-level paging) makes this 64x longer and we start to notice, especially on slower systems like simulators. A 10-second delay for 512k iterations is annoying. But, a 640- second delay is crippling. This does not help if we have extremely sparse physical address spaces, but those are quite rare. We expect that most of the "slow" systems where this matters will also be quite small and non-sparse. To fix this, we track the highest section we've ever encountered. This lets us know when we will *never* see another section_present(), and lets us break out of the loops earlier. Doing the whole for_each_present_section_nr() macro is probably overkill, but it will ensure that any future loop iterations that we grow are more likely to be correct. Kirrill said "It shaved almost 40 seconds from boot time in qemu with 5-level paging enabled for me". Link: http://lkml.kernel.org/r/20170504174434.C45A4735@viggo.jf.intel.com Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
864b9a39 |
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02-Jun-2017 |
Michal Hocko <mhocko@suse.com> |
mm: consider memblock reservations for deferred memory initialization sizing We have seen an early OOM killer invocation on ppc64 systems with crashkernel=4096M: kthreadd invoked oom-killer: gfp_mask=0x16040c0(GFP_KERNEL|__GFP_COMP|__GFP_NOTRACK), nodemask=7, order=0, oom_score_adj=0 kthreadd cpuset=/ mems_allowed=7 CPU: 0 PID: 2 Comm: kthreadd Not tainted 4.4.68-1.gd7fe927-default #1 Call Trace: dump_stack+0xb0/0xf0 (unreliable) dump_header+0xb0/0x258 out_of_memory+0x5f0/0x640 __alloc_pages_nodemask+0xa8c/0xc80 kmem_getpages+0x84/0x1a0 fallback_alloc+0x2a4/0x320 kmem_cache_alloc_node+0xc0/0x2e0 copy_process.isra.25+0x260/0x1b30 _do_fork+0x94/0x470 kernel_thread+0x48/0x60 kthreadd+0x264/0x330 ret_from_kernel_thread+0x5c/0xa4 Mem-Info: active_anon:0 inactive_anon:0 isolated_anon:0 active_file:0 inactive_file:0 isolated_file:0 unevictable:0 dirty:0 writeback:0 unstable:0 slab_reclaimable:5 slab_unreclaimable:73 mapped:0 shmem:0 pagetables:0 bounce:0 free:0 free_pcp:0 free_cma:0 Node 7 DMA free:0kB min:0kB low:0kB high:0kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:52428800kB managed:110016kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:320kB slab_unreclaimable:4672kB kernel_stack:1152kB pagetables:0kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes lowmem_reserve[]: 0 0 0 0 Node 7 DMA: 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB 0*8192kB 0*16384kB = 0kB 0 total pagecache pages 0 pages in swap cache Swap cache stats: add 0, delete 0, find 0/0 Free swap = 0kB Total swap = 0kB 819200 pages RAM 0 pages HighMem/MovableOnly 817481 pages reserved 0 pages cma reserved 0 pages hwpoisoned the reason is that the managed memory is too low (only 110MB) while the rest of the the 50GB is still waiting for the deferred intialization to be done. update_defer_init estimates the initial memoty to initialize to 2GB at least but it doesn't consider any memory allocated in that range. In this particular case we've had Reserving 4096MB of memory at 128MB for crashkernel (System RAM: 51200MB) so the low 2GB is mostly depleted. Fix this by considering memblock allocations in the initial static initialization estimation. Move the max_initialise to reset_deferred_meminit and implement a simple memblock_reserved_memory helper which iterates all reserved blocks and sums the size of all that start below the given address. The cumulative size is than added on top of the initial estimation. This is still not ideal because reset_deferred_meminit doesn't consider holes and so reservation might be above the initial estimation whihch we ignore but let's make the logic simpler until we really need to handle more complicated cases. Fixes: 3a80a7fa7989 ("mm: meminit: initialise a subset of struct pages if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set") Link: http://lkml.kernel.org/r/20170531104010.GI27783@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Mel Gorman <mgorman@suse.de> Tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> [4.2+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b682debd |
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08-May-2017 |
Vlastimil Babka <vbabka@suse.cz> |
mm, compaction: change migrate_async_suitable() to suitable_migration_source() Preparation for making the decisions more complex and depending on compact_control flags. No functional change. Link: http://lkml.kernel.org/r/20170307131545.28577-6-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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2a2e4885 |
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03-May-2017 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: vmscan: fix IO/refault regression in cache workingset transition Since commit 59dc76b0d4df ("mm: vmscan: reduce size of inactive file list") we noticed bigger IO spikes during changes in cache access patterns. The patch in question shrunk the inactive list size to leave more room for the current workingset in the presence of streaming IO. However, workingset transitions that previously happened on the inactive list are now pushed out of memory and incur more refaults to complete. This patch disables active list protection when refaults are being observed. This accelerates workingset transitions, and allows more of the new set to establish itself from memory, without eating into the ability to protect the established workingset during stable periods. The workloads that were measurably affected for us were hit pretty bad by it, with refault/majfault rates doubling and tripling during cache transitions, and the machines sustaining half-hour periods of 100% IO utilization, where they'd previously have sub-minute peaks at 60-90%. Stateful services that handle user data tend to be more conservative with kernel upgrades. As a result we hit most page cache issues with some delay, as was the case here. The severity seemed to warrant a stable tag. Fixes: 59dc76b0d4df ("mm: vmscan: reduce size of inactive file list") Link: http://lkml.kernel.org/r/20170404220052.27593-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: <stable@vger.kernel.org> [4.7+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a6ffdc07 |
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03-May-2017 |
Xishi Qiu <qiuxishi@huawei.com> |
mm: use is_migrate_highatomic() to simplify the code Introduce two helpers, is_migrate_highatomic() and is_migrate_highatomic_page(). Simplify the code, no functional changes. [akpm@linux-foundation.org: use static inlines rather than macros, per mhocko] Link: http://lkml.kernel.org/r/58B94F15.6060606@huawei.com Signed-off-by: Xishi Qiu <qiuxishi@huawei.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Minchan Kim <minchan@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c822f622 |
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03-May-2017 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: delete NR_PAGES_SCANNED and pgdat_reclaimable() NR_PAGES_SCANNED counts number of pages scanned since the last page free event in the allocator. This was used primarily to measure the reclaimability of zones and nodes, and determine when reclaim should give up on them. In that role, it has been replaced in the preceding patches by a different mechanism. Being implemented as an efficient vmstat counter, it was automatically exported to userspace as well. It's however unlikely that anyone outside the kernel is using this counter in any meaningful way. Remove the counter and the unused pgdat_reclaimable(). Link: http://lkml.kernel.org/r/20170228214007.5621-8-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Jia He <hejianet@gmail.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c73322d0 |
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03-May-2017 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: fix 100% CPU kswapd busyloop on unreclaimable nodes Patch series "mm: kswapd spinning on unreclaimable nodes - fixes and cleanups". Jia reported a scenario in which the kswapd of a node indefinitely spins at 100% CPU usage. We have seen similar cases at Facebook. The kernel's current method of judging its ability to reclaim a node (or whether to back off and sleep) is based on the amount of scanned pages in proportion to the amount of reclaimable pages. In Jia's and our scenarios, there are no reclaimable pages in the node, however, and the condition for backing off is never met. Kswapd busyloops in an attempt to restore the watermarks while having nothing to work with. This series reworks the definition of an unreclaimable node based not on scanning but on whether kswapd is able to actually reclaim pages in MAX_RECLAIM_RETRIES (16) consecutive runs. This is the same criteria the page allocator uses for giving up on direct reclaim and invoking the OOM killer. If it cannot free any pages, kswapd will go to sleep and leave further attempts to direct reclaim invocations, which will either make progress and re-enable kswapd, or invoke the OOM killer. Patch #1 fixes the immediate problem Jia reported, the remainder are smaller fixlets, cleanups, and overall phasing out of the old method. Patch #6 is the odd one out. It's a nice cleanup to get_scan_count(), and directly related to #5, but in itself not relevant to the series. If the whole series is too ambitious for 4.11, I would consider the first three patches fixes, the rest cleanups. This patch (of 9): Jia He reports a problem with kswapd spinning at 100% CPU when requesting more hugepages than memory available in the system: $ echo 4000 >/proc/sys/vm/nr_hugepages top - 13:42:59 up 3:37, 1 user, load average: 1.09, 1.03, 1.01 Tasks: 1 total, 1 running, 0 sleeping, 0 stopped, 0 zombie %Cpu(s): 0.0 us, 12.5 sy, 0.0 ni, 85.5 id, 2.0 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem: 31371520 total, 30915136 used, 456384 free, 320 buffers KiB Swap: 6284224 total, 115712 used, 6168512 free. 48192 cached Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 76 root 20 0 0 0 0 R 100.0 0.000 217:17.29 kswapd3 At that time, there are no reclaimable pages left in the node, but as kswapd fails to restore the high watermarks it refuses to go to sleep. Kswapd needs to back away from nodes that fail to balance. Up until commit 1d82de618ddd ("mm, vmscan: make kswapd reclaim in terms of nodes") kswapd had such a mechanism. It considered zones whose theoretically reclaimable pages it had reclaimed six times over as unreclaimable and backed away from them. This guard was erroneously removed as the patch changed the definition of a balanced node. However, simply restoring this code wouldn't help in the case reported here: there *are* no reclaimable pages that could be scanned until the threshold is met. Kswapd would stay awake anyway. Introduce a new and much simpler way of backing off. If kswapd runs through MAX_RECLAIM_RETRIES (16) cycles without reclaiming a single page, make it back off from the node. This is the same number of shots direct reclaim takes before declaring OOM. Kswapd will go to sleep on that node until a direct reclaimer manages to reclaim some pages, thus proving the node reclaimable again. [hannes@cmpxchg.org: check kswapd failure against the cumulative nr_reclaimed count] Link: http://lkml.kernel.org/r/20170306162410.GB2090@cmpxchg.org [shakeelb@google.com: fix condition for throttle_direct_reclaim] Link: http://lkml.kernel.org/r/20170314183228.20152-1-shakeelb@google.com Link: http://lkml.kernel.org/r/20170228214007.5621-2-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Shakeel Butt <shakeelb@google.com> Reported-by: Jia He <hejianet@gmail.com> Tested-by: Jia He <hejianet@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1276ad68 |
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24-Feb-2017 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: vmscan: scan dirty pages even in laptop mode Patch series "mm: vmscan: fix kswapd writeback regression". We noticed a regression on multiple hadoop workloads when moving from 3.10 to 4.0 and 4.6, which involves kswapd getting tangled up in page writeout, causing direct reclaim herds that also don't make progress. I tracked it down to the thrash avoidance efforts after 3.10 that make the kernel better at keeping use-once cache and use-many cache sorted on the inactive and active list, with more aggressive protection of the active list as long as there is inactive cache. Unfortunately, our workload's use-once cache is mostly from streaming writes. Waiting for writes to avoid potential reloads in the future is not a good tradeoff. These patches do the following: 1. Wake the flushers when kswapd sees a lump of dirty pages. It's possible to be below the dirty background limit and still have cache velocity push them through the LRU. So start a-flushin'. 2. Let kswapd only write pages that have been rotated twice. This makes sure we really tried to get all the clean pages on the inactive list before resorting to horrible LRU-order writeback. 3. Move rotating dirty pages off the inactive list. Instead of churning or waiting on page writeback, we'll go after clean active cache. This might lead to thrashing, but in this state memory demand outstrips IO speed anyway, and reads are faster than writes. Mel backported the series to 4.10-rc5 with one minor conflict and ran a couple of tests on it. Mix of read/write random workload didn't show anything interesting. Write-only database didn't show much difference in performance but there were slight reductions in IO -- probably in the noise. simoop did show big differences although not as big as Mel expected. This is Chris Mason's workload that similate the VM activity of hadoop. Mel won't go through the full details but over the samples measured during an hour it reported 4.10.0-rc5 4.10.0-rc5 vanilla johannes-v1r1 Amean p50-Read 21346531.56 ( 0.00%) 21697513.24 ( -1.64%) Amean p95-Read 24700518.40 ( 0.00%) 25743268.98 ( -4.22%) Amean p99-Read 27959842.13 ( 0.00%) 28963271.11 ( -3.59%) Amean p50-Write 1138.04 ( 0.00%) 989.82 ( 13.02%) Amean p95-Write 1106643.48 ( 0.00%) 12104.00 ( 98.91%) Amean p99-Write 1569213.22 ( 0.00%) 36343.38 ( 97.68%) Amean p50-Allocation 85159.82 ( 0.00%) 79120.70 ( 7.09%) Amean p95-Allocation 204222.58 ( 0.00%) 129018.43 ( 36.82%) Amean p99-Allocation 278070.04 ( 0.00%) 183354.43 ( 34.06%) Amean final-p50-Read 21266432.00 ( 0.00%) 21921792.00 ( -3.08%) Amean final-p95-Read 24870912.00 ( 0.00%) 26116096.00 ( -5.01%) Amean final-p99-Read 28147712.00 ( 0.00%) 29523968.00 ( -4.89%) Amean final-p50-Write 1130.00 ( 0.00%) 977.00 ( 13.54%) Amean final-p95-Write 1033216.00 ( 0.00%) 2980.00 ( 99.71%) Amean final-p99-Write 1517568.00 ( 0.00%) 32672.00 ( 97.85%) Amean final-p50-Allocation 86656.00 ( 0.00%) 78464.00 ( 9.45%) Amean final-p95-Allocation 211712.00 ( 0.00%) 116608.00 ( 44.92%) Amean final-p99-Allocation 287232.00 ( 0.00%) 168704.00 ( 41.27%) The latencies are actually completely horrific in comparison to 4.4 (and 4.10-rc5 is worse than 4.9 according to historical data for reasons Mel hasn't analysed yet). Still, 95% of write latency (p95-write) is halved by the series and allocation latency is way down. Direct reclaim activity is one fifth of what it was according to vmstats. Kswapd activity is higher but this is not necessarily surprising. Kswapd efficiency is unchanged at 99% (99% of pages scanned were reclaimed) but direct reclaim efficiency went from 77% to 99% In the vanilla kernel, 627MB of data was written back from reclaim context. With the series, no data was written back. With or without the patch, pages are being immediately reclaimed after writeback completes. However, with the patch, only 1/8th of the pages are reclaimed like this. This patch (of 5): We have an elaborate dirty/writeback throttling mechanism inside the reclaim scanner, but for that to work the pages have to go through shrink_page_list() and get counted for what they are. Otherwise, we mess up the LRU order and don't match reclaim speed to writeback. Especially during deactivation, there is never a reason to skip dirty pages; nothing is even trying to write them out from there. Don't mess up the LRU order for nothing, shuffle these pages along. Link: http://lkml.kernel.org/r/20170123181641.23938-2-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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fd538803 |
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22-Feb-2017 |
Michal Hocko <mhocko@suse.com> |
mm, vmscan: cleanup lru size claculations lruvec_lru_size returns the full size of the LRU list while we sometimes need a value reduced only to eligible zones (e.g. for lowmem requests). inactive_list_is_low is one such user. Later patches will add more of them. Add a new parameter to lruvec_lru_size and allow it filter out zones which are not eligible for the given context. Link: http://lkml.kernel.org/r/20170117103702.28542-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ea57485a |
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24-Jan-2017 |
Vlastimil Babka <vbabka@suse.cz> |
mm, page_alloc: fix check for NULL preferred_zone Patch series "fix premature OOM regression in 4.7+ due to cpuset races". This is v2 of my attempt to fix the recent report based on LTP cpuset stress test [1]. The intention is to go to stable 4.9 LTSS with this, as triggering repeated OOMs is not nice. That's why the patches try to be not too intrusive. Unfortunately why investigating I found that modifying the testcase to use per-VMA policies instead of per-task policies will bring the OOM's back, but that seems to be much older and harder to fix problem. I have posted a RFC [2] but I believe that fixing the recent regressions has a higher priority. Longer-term we might try to think how to fix the cpuset mess in a better and less error prone way. I was for example very surprised to learn, that cpuset updates change not only task->mems_allowed, but also nodemask of mempolicies. Until now I expected the parameter to alloc_pages_nodemask() to be stable. I wonder why do we then treat cpusets specially in get_page_from_freelist() and distinguish HARDWALL etc, when there's unconditional intersection between mempolicy and cpuset. I would expect the nodemask adjustment for saving overhead in g_p_f(), but that clearly doesn't happen in the current form. So we have both crazy complexity and overhead, AFAICS. [1] https://lkml.kernel.org/r/CAFpQJXUq-JuEP=QPidy4p_=FN0rkH5Z-kfB4qBvsf6jMS87Edg@mail.gmail.com [2] https://lkml.kernel.org/r/7c459f26-13a6-a817-e508-b65b903a8378@suse.cz This patch (of 4): Since commit c33d6c06f60f ("mm, page_alloc: avoid looking up the first zone in a zonelist twice") we have a wrong check for NULL preferred_zone, which can theoretically happen due to concurrent cpuset modification. We check the zoneref pointer which is never NULL and we should check the zone pointer. Also document this in first_zones_zonelist() comment per Michal Hocko. Fixes: c33d6c06f60f ("mm, page_alloc: avoid looking up the first zone in a zonelist twice") Link: http://lkml.kernel.org/r/20170120103843.24587-2-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Ganapatrao Kulkarni <gpkulkarni@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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9efeccac |
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10-Dec-2016 |
Michael S. Tsirkin <mst@redhat.com> |
linux: drop __bitwise__ everywhere __bitwise__ used to mean "yes, please enable sparse checks unconditionally", but now that we dropped __CHECK_ENDIAN__ __bitwise is exactly the same. There aren't many users, replace it by __bitwise everywhere. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Stefan Schmidt <stefan@osg.samsung.com> Acked-by: Krzysztof Kozlowski <krzk@kernel.org> Akced-by: Lee Duncan <lduncan@suse.com>
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9dcb8b68 |
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26-Oct-2016 |
Linus Torvalds <torvalds@linux-foundation.org> |
mm: remove per-zone hashtable of bitlock waitqueues The per-zone waitqueues exist because of a scalability issue with the page waitqueues on some NUMA machines, but it turns out that they hurt normal loads, and now with the vmalloced stacks they also end up breaking gfs2 that uses a bit_wait on a stack object: wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE) where 'gh' can be a reference to the local variable 'mount_gh' on the stack of fill_super(). The reason the per-zone hash table breaks for this case is that there is no "zone" for virtual allocations, and trying to look up the physical page to get at it will fail (with a BUG_ON()). It turns out that I actually complained to the mm people about the per-zone hash table for another reason just a month ago: the zone lookup also hurts the regular use of "unlock_page()" a lot, because the zone lookup ends up forcing several unnecessary cache misses and generates horrible code. As part of that earlier discussion, we had a much better solution for the NUMA scalability issue - by just making the page lock have a separate contention bit, the waitqueue doesn't even have to be looked at for the normal case. Peter Zijlstra already has a patch for that, but let's see if anybody even notices. In the meantime, let's fix the actual gfs2 breakage by simplifying the bitlock waitqueues and removing the per-zone issue. Reported-by: Andreas Gruenbacher <agruenba@redhat.com> Tested-by: Bob Peterson <rpeterso@redhat.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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6aa303de |
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01-Sep-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, vmscan: only allocate and reclaim from zones with pages managed by the buddy allocator Firmware Assisted Dump (FA_DUMP) on ppc64 reserves substantial amounts of memory when booting a secondary kernel. Srikar Dronamraju reported that multiple nodes may have no memory managed by the buddy allocator but still return true for populated_zone(). Commit 1d82de618ddd ("mm, vmscan: make kswapd reclaim in terms of nodes") was reported to cause kswapd to spin at 100% CPU usage when fadump was enabled. The old code happened to deal with the situation of a populated node with zero free pages by co-incidence but the current code tries to reclaim populated zones without realising that is impossible. We cannot just convert populated_zone() as many existing users really need to check for present_pages. This patch introduces a managed_zone() helper and uses it in the few cases where it is critical that the check is made for managed pages -- zonelist construction and page reclaim. Link: http://lkml.kernel.org/r/20160831195104.GB8119@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d30dd8be |
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28-Jul-2016 |
Andy Lutomirski <luto@kernel.org> |
mm: track NR_KERNEL_STACK in KiB instead of number of stacks Currently, NR_KERNEL_STACK tracks the number of kernel stacks in a zone. This only makes sense if each kernel stack exists entirely in one zone, and allowing vmapped stacks could break this assumption. Since frv has THREAD_SIZE < PAGE_SIZE, we need to track kernel stack allocations in a unit that divides both THREAD_SIZE and PAGE_SIZE on all architectures. Keep it simple and use KiB. Link: http://lkml.kernel.org/r/083c71e642c5fa5f1b6898902e1b2db7b48940d4.1468523549.git.luto@kernel.org Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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5a1c84b4 |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm: remove reclaim and compaction retry approximations If per-zone LRU accounting is available then there is no point approximating whether reclaim and compaction should retry based on pgdat statistics. This is effectively a revert of "mm, vmstat: remove zone and node double accounting by approximating retries" with the difference that inactive/active stats are still available. This preserves the history of why the approximation was retried and why it had to be reverted to handle OOM kills on 32-bit systems. Link: http://lkml.kernel.org/r/1469110261-7365-4-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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71c799f4 |
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28-Jul-2016 |
Minchan Kim <minchan@kernel.org> |
mm: add per-zone lru list stat When I did stress test with hackbench, I got OOM message frequently which didn't ever happen in zone-lru. gfp_mask=0x26004c0(GFP_KERNEL|__GFP_REPEAT|__GFP_NOTRACK), order=0 .. .. __alloc_pages_nodemask+0xe52/0xe60 ? new_slab+0x39c/0x3b0 new_slab+0x39c/0x3b0 ___slab_alloc.constprop.87+0x6da/0x840 ? __alloc_skb+0x3c/0x260 ? _raw_spin_unlock_irq+0x27/0x60 ? trace_hardirqs_on_caller+0xec/0x1b0 ? finish_task_switch+0xa6/0x220 ? poll_select_copy_remaining+0x140/0x140 __slab_alloc.isra.81.constprop.86+0x40/0x6d ? __alloc_skb+0x3c/0x260 kmem_cache_alloc+0x22c/0x260 ? __alloc_skb+0x3c/0x260 __alloc_skb+0x3c/0x260 alloc_skb_with_frags+0x4e/0x1a0 sock_alloc_send_pskb+0x16a/0x1b0 ? wait_for_unix_gc+0x31/0x90 ? alloc_set_pte+0x2ad/0x310 unix_stream_sendmsg+0x28d/0x340 sock_sendmsg+0x2d/0x40 sock_write_iter+0x6c/0xc0 __vfs_write+0xc0/0x120 vfs_write+0x9b/0x1a0 ? __might_fault+0x49/0xa0 SyS_write+0x44/0x90 do_fast_syscall_32+0xa6/0x1e0 sysenter_past_esp+0x45/0x74 Mem-Info: active_anon:104698 inactive_anon:105791 isolated_anon:192 active_file:433 inactive_file:283 isolated_file:22 unevictable:0 dirty:0 writeback:296 unstable:0 slab_reclaimable:6389 slab_unreclaimable:78927 mapped:474 shmem:0 pagetables:101426 bounce:0 free:10518 free_pcp:334 free_cma:0 Node 0 active_anon:418792kB inactive_anon:423164kB active_file:1732kB inactive_file:1132kB unevictable:0kB isolated(anon):768kB isolated(file):88kB mapped:1896kB dirty:0kB writeback:1184kB shmem:0kB writeback_tmp:0kB unstable:0kB pages_scanned:1478632 all_unreclaimable? yes DMA free:3304kB min:68kB low:84kB high:100kB present:15992kB managed:15916kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:4088kB kernel_stack:0kB pagetables:2480kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB lowmem_reserve[]: 0 809 1965 1965 Normal free:3436kB min:3604kB low:4504kB high:5404kB present:897016kB managed:858460kB mlocked:0kB slab_reclaimable:25556kB slab_unreclaimable:311712kB kernel_stack:164608kB pagetables:30844kB bounce:0kB free_pcp:620kB local_pcp:104kB free_cma:0kB lowmem_reserve[]: 0 0 9247 9247 HighMem free:33808kB min:512kB low:1796kB high:3080kB present:1183736kB managed:1183736kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:372252kB bounce:0kB free_pcp:428kB local_pcp:72kB free_cma:0kB lowmem_reserve[]: 0 0 0 0 DMA: 2*4kB (UM) 2*8kB (UM) 0*16kB 1*32kB (U) 1*64kB (U) 2*128kB (UM) 1*256kB (U) 1*512kB (M) 0*1024kB 1*2048kB (U) 0*4096kB = 3192kB Normal: 33*4kB (MH) 79*8kB (ME) 11*16kB (M) 4*32kB (M) 2*64kB (ME) 2*128kB (EH) 7*256kB (EH) 0*512kB 0*1024kB 0*2048kB 0*4096kB = 3244kB HighMem: 2590*4kB (UM) 1568*8kB (UM) 491*16kB (UM) 60*32kB (UM) 6*64kB (M) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 33064kB Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB 25121 total pagecache pages 24160 pages in swap cache Swap cache stats: add 86371, delete 62211, find 42865/60187 Free swap = 4015560kB Total swap = 4192252kB 524186 pages RAM 295934 pages HighMem/MovableOnly 9658 pages reserved 0 pages cma reserved The order-0 allocation for normal zone failed while there are a lot of reclaimable memory(i.e., anonymous memory with free swap). I wanted to analyze the problem but it was hard because we removed per-zone lru stat so I couldn't know how many of anonymous memory there are in normal/dma zone. When we investigate OOM problem, reclaimable memory count is crucial stat to find a problem. Without it, it's hard to parse the OOM message so I believe we should keep it. With per-zone lru stat, gfp_mask=0x26004c0(GFP_KERNEL|__GFP_REPEAT|__GFP_NOTRACK), order=0 Mem-Info: active_anon:101103 inactive_anon:102219 isolated_anon:0 active_file:503 inactive_file:544 isolated_file:0 unevictable:0 dirty:0 writeback:34 unstable:0 slab_reclaimable:6298 slab_unreclaimable:74669 mapped:863 shmem:0 pagetables:100998 bounce:0 free:23573 free_pcp:1861 free_cma:0 Node 0 active_anon:404412kB inactive_anon:409040kB active_file:2012kB inactive_file:2176kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:3452kB dirty:0kB writeback:136kB shmem:0kB writeback_tmp:0kB unstable:0kB pages_scanned:1320845 all_unreclaimable? yes DMA free:3296kB min:68kB low:84kB high:100kB active_anon:5540kB inactive_anon:0kB active_file:0kB inactive_file:0kB present:15992kB managed:15916kB mlocked:0kB slab_reclaimable:248kB slab_unreclaimable:2628kB kernel_stack:792kB pagetables:2316kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB lowmem_reserve[]: 0 809 1965 1965 Normal free:3600kB min:3604kB low:4504kB high:5404kB active_anon:86304kB inactive_anon:0kB active_file:160kB inactive_file:376kB present:897016kB managed:858524kB mlocked:0kB slab_reclaimable:24944kB slab_unreclaimable:296048kB kernel_stack:163832kB pagetables:35892kB bounce:0kB free_pcp:3076kB local_pcp:656kB free_cma:0kB lowmem_reserve[]: 0 0 9247 9247 HighMem free:86156kB min:512kB low:1796kB high:3080kB active_anon:312852kB inactive_anon:410024kB active_file:1924kB inactive_file:2012kB present:1183736kB managed:1183736kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:365784kB bounce:0kB free_pcp:3868kB local_pcp:720kB free_cma:0kB lowmem_reserve[]: 0 0 0 0 DMA: 8*4kB (UM) 8*8kB (UM) 4*16kB (M) 2*32kB (UM) 2*64kB (UM) 1*128kB (M) 3*256kB (UME) 2*512kB (UE) 1*1024kB (E) 0*2048kB 0*4096kB = 3296kB Normal: 240*4kB (UME) 160*8kB (UME) 23*16kB (ME) 3*32kB (UE) 3*64kB (UME) 2*128kB (ME) 1*256kB (U) 0*512kB 0*1024kB 0*2048kB 0*4096kB = 3408kB HighMem: 10942*4kB (UM) 3102*8kB (UM) 866*16kB (UM) 76*32kB (UM) 11*64kB (UM) 4*128kB (UM) 1*256kB (M) 0*512kB 0*1024kB 0*2048kB 0*4096kB = 86344kB Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB 54409 total pagecache pages 53215 pages in swap cache Swap cache stats: add 300982, delete 247765, find 157978/226539 Free swap = 3803244kB Total swap = 4192252kB 524186 pages RAM 295934 pages HighMem/MovableOnly 9642 pages reserved 0 pages cma reserved With that, we can see normal zone has a 86M reclaimable memory so we can know something goes wrong(I will fix the problem in next patch) in reclaim. [mgorman@techsingularity.net: rename zone LRU stats in /proc/vmstat] Link: http://lkml.kernel.org/r/20160725072300.GK10438@techsingularity.net Link: http://lkml.kernel.org/r/1469110261-7365-2-git-send-email-mgorman@techsingularity.net Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bca67592 |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, vmstat: remove zone and node double accounting by approximating retries The number of LRU pages, dirty pages and writeback pages must be accounted for on both zones and nodes because of the reclaim retry logic, compaction retry logic and highmem calculations all depending on per-zone stats. Many lowmem allocations are immune from OOM kill due to a check in __alloc_pages_may_oom for (ac->high_zoneidx < ZONE_NORMAL) since commit 03668b3ceb0c ("oom: avoid oom killer for lowmem allocations"). The exception is costly high-order allocations or allocations that cannot fail. If the __alloc_pages_may_oom avoids OOM-kill for low-order lowmem allocations then it would fall through to __alloc_pages_direct_compact. This patch will blindly retry reclaim for zone-constrained allocations in should_reclaim_retry up to MAX_RECLAIM_RETRIES. This is not ideal but without per-zone stats there are not many alternatives. The impact it that zone-constrained allocations may delay before considering the OOM killer. As there is no guarantee enough memory can ever be freed to satisfy compaction, this patch avoids retrying compaction for zone-contrained allocations. In combination, that means that the per-node stats can be used when deciding whether to continue reclaim using a rough approximation. While it is possible this will make the wrong decision on occasion, it will not infinite loop as the number of reclaim attempts is capped by MAX_RECLAIM_RETRIES. The final step is calculating the number of dirtyable highmem pages. As those calculations only care about the global count of file pages in highmem. This patch uses a global counter used instead of per-zone stats as it is sufficient. In combination, this allows the per-zone LRU and dirty state counters to be removed. [mgorman@techsingularity.net: fix acct_highmem_file_pages()] Link: http://lkml.kernel.org/r/1468853426-12858-4-git-send-email-mgorman@techsingularity.netLink: http://lkml.kernel.org/r/1467970510-21195-35-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Suggested by: Michal Hocko <mhocko@kernel.org> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e6cbd7f2 |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, page_alloc: remove fair zone allocation policy The fair zone allocation policy interleaves allocation requests between zones to avoid an age inversion problem whereby new pages are reclaimed to balance a zone. Reclaim is now node-based so this should no longer be an issue and the fair zone allocation policy is not free. This patch removes it. Link: http://lkml.kernel.org/r/1467970510-21195-30-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a5f5f91d |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm: convert zone_reclaim to node_reclaim As reclaim is now per-node based, convert zone_reclaim to be node_reclaim. It is possible that a node will be reclaimed multiple times if it has multiple zones but this is unavoidable without caching all nodes traversed so far. The documentation and interface to userspace is the same from a configuration perspective and will will be similar in behaviour unless the node-local allocation requests were also limited to lower zones. Link: http://lkml.kernel.org/r/1467970510-21195-24-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c4a25635 |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm: move vmscan writes and file write accounting to the node As reclaim is now node-based, it follows that page write activity due to page reclaim should also be accounted for on the node. For consistency, also account page writes and page dirtying on a per-node basis. After this patch, there are a few remaining zone counters that may appear strange but are fine. NUMA stats are still per-zone as this is a user-space interface that tools consume. NR_MLOCK, NR_SLAB_*, NR_PAGETABLE, NR_KERNEL_STACK and NR_BOUNCE are all allocations that potentially pin low memory and cannot trivially be reclaimed on demand. This information is still useful for debugging a page allocation failure warning. Link: http://lkml.kernel.org/r/1467970510-21195-21-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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11fb9989 |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm: move most file-based accounting to the node There are now a number of accounting oddities such as mapped file pages being accounted for on the node while the total number of file pages are accounted on the zone. This can be coped with to some extent but it's confusing so this patch moves the relevant file-based accounted. Due to throttling logic in the page allocator for reliable OOM detection, it is still necessary to track dirty and writeback pages on a per-zone basis. [mgorman@techsingularity.net: fix NR_ZONE_WRITE_PENDING accounting] Link: http://lkml.kernel.org/r/1468404004-5085-5-git-send-email-mgorman@techsingularity.net Link: http://lkml.kernel.org/r/1467970510-21195-20-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4b9d0fab |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm: rename NR_ANON_PAGES to NR_ANON_MAPPED NR_FILE_PAGES is the number of file pages. NR_FILE_MAPPED is the number of mapped file pages. NR_ANON_PAGES is the number of mapped anon pages. This is unhelpful naming as it's easy to confuse NR_FILE_MAPPED and NR_ANON_PAGES for mapped pages. This patch renames NR_ANON_PAGES so we have NR_FILE_PAGES is the number of file pages. NR_FILE_MAPPED is the number of mapped file pages. NR_ANON_MAPPED is the number of mapped anon pages. Link: http://lkml.kernel.org/r/1467970510-21195-19-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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50658e2e |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm: move page mapped accounting to the node Reclaim makes decisions based on the number of pages that are mapped but it's mixing node and zone information. Account NR_FILE_MAPPED and NR_ANON_PAGES pages on the node. Link: http://lkml.kernel.org/r/1467970510-21195-18-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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281e3726 |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, page_alloc: consider dirtyable memory in terms of nodes Historically dirty pages were spread among zones but now that LRUs are per-node it is more appropriate to consider dirty pages in a node. Link: http://lkml.kernel.org/r/1467970510-21195-17-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1e6b1085 |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, workingset: make working set detection node-aware Working set and refault detection is still zone-based, fix it. Link: http://lkml.kernel.org/r/1467970510-21195-16-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a9dd0a83 |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, vmscan: make shrink_node decisions more node-centric Earlier patches focused on having direct reclaim and kswapd use data that is node-centric for reclaiming but shrink_node() itself still uses too much zone information. This patch removes unnecessary zone-based information with the most important decision being whether to continue reclaim or not. Some memcg APIs are adjusted as a result even though memcg itself still uses some zone information. [mgorman@techsingularity.net: optimization] Link: http://lkml.kernel.org/r/1468588165-12461-2-git-send-email-mgorman@techsingularity.net Link: http://lkml.kernel.org/r/1467970510-21195-14-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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38087d9b |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, vmscan: simplify the logic deciding whether kswapd sleeps kswapd goes through some complex steps trying to figure out if it should stay awake based on the classzone_idx and the requested order. It is unnecessarily complex and passes in an invalid classzone_idx to balance_pgdat(). What matters most of all is whether a larger order has been requsted and whether kswapd successfully reclaimed at the previous order. This patch irons out the logic to check just that and the end result is less headache inducing. Link: http://lkml.kernel.org/r/1467970510-21195-10-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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0f661148 |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, mmzone: clarify the usage of zone padding Zone padding separates write-intensive fields used by page allocation, compaction and vmstats but the comments are a little misleading and need clarification. Link: http://lkml.kernel.org/r/1467970510-21195-5-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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599d0c95 |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, vmscan: move LRU lists to node This moves the LRU lists from the zone to the node and related data such as counters, tracing, congestion tracking and writeback tracking. Unfortunately, due to reclaim and compaction retry logic, it is necessary to account for the number of LRU pages on both zone and node logic. Most reclaim logic is based on the node counters but the retry logic uses the zone counters which do not distinguish inactive and active sizes. It would be possible to leave the LRU counters on a per-zone basis but it's a heavier calculation across multiple cache lines that is much more frequent than the retry checks. Other than the LRU counters, this is mostly a mechanical patch but note that it introduces a number of anomalies. For example, the scans are per-zone but using per-node counters. We also mark a node as congested when a zone is congested. This causes weird problems that are fixed later but is easier to review. In the event that there is excessive overhead on 32-bit systems due to the nodes being on LRU then there are two potential solutions 1. Long-term isolation of highmem pages when reclaim is lowmem When pages are skipped, they are immediately added back onto the LRU list. If lowmem reclaim persisted for long periods of time, the same highmem pages get continually scanned. The idea would be that lowmem keeps those pages on a separate list until a reclaim for highmem pages arrives that splices the highmem pages back onto the LRU. It potentially could be implemented similar to the UNEVICTABLE list. That would reduce the skip rate with the potential corner case is that highmem pages have to be scanned and reclaimed to free lowmem slab pages. 2. Linear scan lowmem pages if the initial LRU shrink fails This will break LRU ordering but may be preferable and faster during memory pressure than skipping LRU pages. Link: http://lkml.kernel.org/r/1467970510-21195-4-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a52633d8 |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, vmscan: move lru_lock to the node Node-based reclaim requires node-based LRUs and locking. This is a preparation patch that just moves the lru_lock to the node so later patches are easier to review. It is a mechanical change but note this patch makes contention worse because the LRU lock is hotter and direct reclaim and kswapd can contend on the same lock even when reclaiming from different zones. Link: http://lkml.kernel.org/r/1467970510-21195-3-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Minchan Kim <minchan@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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75ef7184 |
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28-Jul-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, vmstat: add infrastructure for per-node vmstats Patchset: "Move LRU page reclaim from zones to nodes v9" This series moves LRUs from the zones to the node. While this is a current rebase, the test results were based on mmotm as of June 23rd. Conceptually, this series is simple but there are a lot of details. Some of the broad motivations for this are; 1. The residency of a page partially depends on what zone the page was allocated from. This is partially combatted by the fair zone allocation policy but that is a partial solution that introduces overhead in the page allocator paths. 2. Currently, reclaim on node 0 behaves slightly different to node 1. For example, direct reclaim scans in zonelist order and reclaims even if the zone is over the high watermark regardless of the age of pages in that LRU. Kswapd on the other hand starts reclaim on the highest unbalanced zone. A difference in distribution of file/anon pages due to when they were allocated results can result in a difference in again. While the fair zone allocation policy mitigates some of the problems here, the page reclaim results on a multi-zone node will always be different to a single-zone node. it was scheduled on as a result. 3. kswapd and the page allocator scan zones in the opposite order to avoid interfering with each other but it's sensitive to timing. This mitigates the page allocator using pages that were allocated very recently in the ideal case but it's sensitive to timing. When kswapd is allocating from lower zones then it's great but during the rebalancing of the highest zone, the page allocator and kswapd interfere with each other. It's worse if the highest zone is small and difficult to balance. 4. slab shrinkers are node-based which makes it harder to identify the exact relationship between slab reclaim and LRU reclaim. The reason we have zone-based reclaim is that we used to have large highmem zones in common configurations and it was necessary to quickly find ZONE_NORMAL pages for reclaim. Today, this is much less of a concern as machines with lots of memory will (or should) use 64-bit kernels. Combinations of 32-bit hardware and 64-bit hardware are rare. Machines that do use highmem should have relatively low highmem:lowmem ratios than we worried about in the past. Conceptually, moving to node LRUs should be easier to understand. The page allocator plays fewer tricks to game reclaim and reclaim behaves similarly on all nodes. The series has been tested on a 16 core UMA machine and a 2-socket 48 core NUMA machine. The UMA results are presented in most cases as the NUMA machine behaved similarly. pagealloc --------- This is a microbenchmark that shows the benefit of removing the fair zone allocation policy. It was tested uip to order-4 but only orders 0 and 1 are shown as the other orders were comparable. 4.7.0-rc4 4.7.0-rc4 mmotm-20160623 nodelru-v9 Min total-odr0-1 490.00 ( 0.00%) 457.00 ( 6.73%) Min total-odr0-2 347.00 ( 0.00%) 329.00 ( 5.19%) Min total-odr0-4 288.00 ( 0.00%) 273.00 ( 5.21%) Min total-odr0-8 251.00 ( 0.00%) 239.00 ( 4.78%) Min total-odr0-16 234.00 ( 0.00%) 222.00 ( 5.13%) Min total-odr0-32 223.00 ( 0.00%) 211.00 ( 5.38%) Min total-odr0-64 217.00 ( 0.00%) 208.00 ( 4.15%) Min total-odr0-128 214.00 ( 0.00%) 204.00 ( 4.67%) Min total-odr0-256 250.00 ( 0.00%) 230.00 ( 8.00%) Min total-odr0-512 271.00 ( 0.00%) 269.00 ( 0.74%) Min total-odr0-1024 291.00 ( 0.00%) 282.00 ( 3.09%) Min total-odr0-2048 303.00 ( 0.00%) 296.00 ( 2.31%) Min total-odr0-4096 311.00 ( 0.00%) 309.00 ( 0.64%) Min total-odr0-8192 316.00 ( 0.00%) 314.00 ( 0.63%) Min total-odr0-16384 317.00 ( 0.00%) 315.00 ( 0.63%) Min total-odr1-1 742.00 ( 0.00%) 712.00 ( 4.04%) Min total-odr1-2 562.00 ( 0.00%) 530.00 ( 5.69%) Min total-odr1-4 457.00 ( 0.00%) 433.00 ( 5.25%) Min total-odr1-8 411.00 ( 0.00%) 381.00 ( 7.30%) Min total-odr1-16 381.00 ( 0.00%) 356.00 ( 6.56%) Min total-odr1-32 372.00 ( 0.00%) 346.00 ( 6.99%) Min total-odr1-64 372.00 ( 0.00%) 343.00 ( 7.80%) Min total-odr1-128 375.00 ( 0.00%) 351.00 ( 6.40%) Min total-odr1-256 379.00 ( 0.00%) 351.00 ( 7.39%) Min total-odr1-512 385.00 ( 0.00%) 355.00 ( 7.79%) Min total-odr1-1024 386.00 ( 0.00%) 358.00 ( 7.25%) Min total-odr1-2048 390.00 ( 0.00%) 362.00 ( 7.18%) Min total-odr1-4096 390.00 ( 0.00%) 362.00 ( 7.18%) Min total-odr1-8192 388.00 ( 0.00%) 363.00 ( 6.44%) This shows a steady improvement throughout. The primary benefit is from reduced system CPU usage which is obvious from the overall times; 4.7.0-rc4 4.7.0-rc4 mmotm-20160623nodelru-v8 User 189.19 191.80 System 2604.45 2533.56 Elapsed 2855.30 2786.39 The vmstats also showed that the fair zone allocation policy was definitely removed as can be seen here; 4.7.0-rc3 4.7.0-rc3 mmotm-20160623 nodelru-v8 DMA32 allocs 28794729769 0 Normal allocs 48432501431 77227309877 Movable allocs 0 0 tiobench on ext4 ---------------- tiobench is a benchmark that artifically benefits if old pages remain resident while new pages get reclaimed. The fair zone allocation policy mitigates this problem so pages age fairly. While the benchmark has problems, it is important that tiobench performance remains constant as it implies that page aging problems that the fair zone allocation policy fixes are not re-introduced. 4.7.0-rc4 4.7.0-rc4 mmotm-20160623 nodelru-v9 Min PotentialReadSpeed 89.65 ( 0.00%) 90.21 ( 0.62%) Min SeqRead-MB/sec-1 82.68 ( 0.00%) 82.01 ( -0.81%) Min SeqRead-MB/sec-2 72.76 ( 0.00%) 72.07 ( -0.95%) Min SeqRead-MB/sec-4 75.13 ( 0.00%) 74.92 ( -0.28%) Min SeqRead-MB/sec-8 64.91 ( 0.00%) 65.19 ( 0.43%) Min SeqRead-MB/sec-16 62.24 ( 0.00%) 62.22 ( -0.03%) Min RandRead-MB/sec-1 0.88 ( 0.00%) 0.88 ( 0.00%) Min RandRead-MB/sec-2 0.95 ( 0.00%) 0.92 ( -3.16%) Min RandRead-MB/sec-4 1.43 ( 0.00%) 1.34 ( -6.29%) Min RandRead-MB/sec-8 1.61 ( 0.00%) 1.60 ( -0.62%) Min RandRead-MB/sec-16 1.80 ( 0.00%) 1.90 ( 5.56%) Min SeqWrite-MB/sec-1 76.41 ( 0.00%) 76.85 ( 0.58%) Min SeqWrite-MB/sec-2 74.11 ( 0.00%) 73.54 ( -0.77%) Min SeqWrite-MB/sec-4 80.05 ( 0.00%) 80.13 ( 0.10%) Min SeqWrite-MB/sec-8 72.88 ( 0.00%) 73.20 ( 0.44%) Min SeqWrite-MB/sec-16 75.91 ( 0.00%) 76.44 ( 0.70%) Min RandWrite-MB/sec-1 1.18 ( 0.00%) 1.14 ( -3.39%) Min RandWrite-MB/sec-2 1.02 ( 0.00%) 1.03 ( 0.98%) Min RandWrite-MB/sec-4 1.05 ( 0.00%) 0.98 ( -6.67%) Min RandWrite-MB/sec-8 0.89 ( 0.00%) 0.92 ( 3.37%) Min RandWrite-MB/sec-16 0.92 ( 0.00%) 0.93 ( 1.09%) 4.7.0-rc4 4.7.0-rc4 mmotm-20160623 approx-v9 User 645.72 525.90 System 403.85 331.75 Elapsed 6795.36 6783.67 This shows that the series has little or not impact on tiobench which is desirable and a reduction in system CPU usage. It indicates that the fair zone allocation policy was removed in a manner that didn't reintroduce one class of page aging bug. There were only minor differences in overall reclaim activity 4.7.0-rc4 4.7.0-rc4 mmotm-20160623nodelru-v8 Minor Faults 645838 647465 Major Faults 573 640 Swap Ins 0 0 Swap Outs 0 0 DMA allocs 0 0 DMA32 allocs 46041453 44190646 Normal allocs 78053072 79887245 Movable allocs 0 0 Allocation stalls 24 67 Stall zone DMA 0 0 Stall zone DMA32 0 0 Stall zone Normal 0 2 Stall zone HighMem 0 0 Stall zone Movable 0 65 Direct pages scanned 10969 30609 Kswapd pages scanned 93375144 93492094 Kswapd pages reclaimed 93372243 93489370 Direct pages reclaimed 10969 30609 Kswapd efficiency 99% 99% Kswapd velocity 13741.015 13781.934 Direct efficiency 100% 100% Direct velocity 1.614 4.512 Percentage direct scans 0% 0% kswapd activity was roughly comparable. There were differences in direct reclaim activity but negligible in the context of the overall workload (velocity of 4 pages per second with the patches applied, 1.6 pages per second in the baseline kernel). pgbench read-only large configuration on ext4 --------------------------------------------- pgbench is a database benchmark that can be sensitive to page reclaim decisions. This also checks if removing the fair zone allocation policy is safe pgbench Transactions 4.7.0-rc4 4.7.0-rc4 mmotm-20160623 nodelru-v8 Hmean 1 188.26 ( 0.00%) 189.78 ( 0.81%) Hmean 5 330.66 ( 0.00%) 328.69 ( -0.59%) Hmean 12 370.32 ( 0.00%) 380.72 ( 2.81%) Hmean 21 368.89 ( 0.00%) 369.00 ( 0.03%) Hmean 30 382.14 ( 0.00%) 360.89 ( -5.56%) Hmean 32 428.87 ( 0.00%) 432.96 ( 0.95%) Negligible differences again. As with tiobench, overall reclaim activity was comparable. bonnie++ on ext4 ---------------- No interesting performance difference, negligible differences on reclaim stats. paralleldd on ext4 ------------------ This workload uses varying numbers of dd instances to read large amounts of data from disk. 4.7.0-rc3 4.7.0-rc3 mmotm-20160623 nodelru-v9 Amean Elapsd-1 186.04 ( 0.00%) 189.41 ( -1.82%) Amean Elapsd-3 192.27 ( 0.00%) 191.38 ( 0.46%) Amean Elapsd-5 185.21 ( 0.00%) 182.75 ( 1.33%) Amean Elapsd-7 183.71 ( 0.00%) 182.11 ( 0.87%) Amean Elapsd-12 180.96 ( 0.00%) 181.58 ( -0.35%) Amean Elapsd-16 181.36 ( 0.00%) 183.72 ( -1.30%) 4.7.0-rc4 4.7.0-rc4 mmotm-20160623 nodelru-v9 User 1548.01 1552.44 System 8609.71 8515.08 Elapsed 3587.10 3594.54 There is little or no change in performance but some drop in system CPU usage. 4.7.0-rc3 4.7.0-rc3 mmotm-20160623 nodelru-v9 Minor Faults 362662 367360 Major Faults 1204 1143 Swap Ins 22 0 Swap Outs 2855 1029 DMA allocs 0 0 DMA32 allocs 31409797 28837521 Normal allocs 46611853 49231282 Movable allocs 0 0 Direct pages scanned 0 0 Kswapd pages scanned 40845270 40869088 Kswapd pages reclaimed 40830976 40855294 Direct pages reclaimed 0 0 Kswapd efficiency 99% 99% Kswapd velocity 11386.711 11369.769 Direct efficiency 100% 100% Direct velocity 0.000 0.000 Percentage direct scans 0% 0% Page writes by reclaim 2855 1029 Page writes file 0 0 Page writes anon 2855 1029 Page reclaim immediate 771 1628 Sector Reads 293312636 293536360 Sector Writes 18213568 18186480 Page rescued immediate 0 0 Slabs scanned 128257 132747 Direct inode steals 181 56 Kswapd inode steals 59 1131 It basically shows that kswapd was active at roughly the same rate in both kernels. There was also comparable slab scanning activity and direct reclaim was avoided in both cases. There appears to be a large difference in numbers of inodes reclaimed but the workload has few active inodes and is likely a timing artifact. stutter ------- stutter simulates a simple workload. One part uses a lot of anonymous memory, a second measures mmap latency and a third copies a large file. The primary metric is checking for mmap latency. stutter 4.7.0-rc4 4.7.0-rc4 mmotm-20160623 nodelru-v8 Min mmap 16.6283 ( 0.00%) 13.4258 ( 19.26%) 1st-qrtle mmap 54.7570 ( 0.00%) 34.9121 ( 36.24%) 2nd-qrtle mmap 57.3163 ( 0.00%) 46.1147 ( 19.54%) 3rd-qrtle mmap 58.9976 ( 0.00%) 47.1882 ( 20.02%) Max-90% mmap 59.7433 ( 0.00%) 47.4453 ( 20.58%) Max-93% mmap 60.1298 ( 0.00%) 47.6037 ( 20.83%) Max-95% mmap 73.4112 ( 0.00%) 82.8719 (-12.89%) Max-99% mmap 92.8542 ( 0.00%) 88.8870 ( 4.27%) Max mmap 1440.6569 ( 0.00%) 121.4201 ( 91.57%) Mean mmap 59.3493 ( 0.00%) 42.2991 ( 28.73%) Best99%Mean mmap 57.2121 ( 0.00%) 41.8207 ( 26.90%) Best95%Mean mmap 55.9113 ( 0.00%) 39.9620 ( 28.53%) Best90%Mean mmap 55.6199 ( 0.00%) 39.3124 ( 29.32%) Best50%Mean mmap 53.2183 ( 0.00%) 33.1307 ( 37.75%) Best10%Mean mmap 45.9842 ( 0.00%) 20.4040 ( 55.63%) Best5%Mean mmap 43.2256 ( 0.00%) 17.9654 ( 58.44%) Best1%Mean mmap 32.9388 ( 0.00%) 16.6875 ( 49.34%) This shows a number of improvements with the worst-case outlier greatly improved. Some of the vmstats are interesting 4.7.0-rc4 4.7.0-rc4 mmotm-20160623nodelru-v8 Swap Ins 163 502 Swap Outs 0 0 DMA allocs 0 0 DMA32 allocs 618719206 1381662383 Normal allocs 891235743 564138421 Movable allocs 0 0 Allocation stalls 2603 1 Direct pages scanned 216787 2 Kswapd pages scanned 50719775 41778378 Kswapd pages reclaimed 41541765 41777639 Direct pages reclaimed 209159 0 Kswapd efficiency 81% 99% Kswapd velocity 16859.554 14329.059 Direct efficiency 96% 0% Direct velocity 72.061 0.001 Percentage direct scans 0% 0% Page writes by reclaim 6215049 0 Page writes file 6215049 0 Page writes anon 0 0 Page reclaim immediate 70673 90 Sector Reads 81940800 81680456 Sector Writes 100158984 98816036 Page rescued immediate 0 0 Slabs scanned 1366954 22683 While this is not guaranteed in all cases, this particular test showed a large reduction in direct reclaim activity. It's also worth noting that no page writes were issued from reclaim context. This series is not without its hazards. There are at least three areas that I'm concerned with even though I could not reproduce any problems in that area. 1. Reclaim/compaction is going to be affected because the amount of reclaim is no longer targetted at a specific zone. Compaction works on a per-zone basis so there is no guarantee that reclaiming a few THP's worth page pages will have a positive impact on compaction success rates. 2. The Slab/LRU reclaim ratio is affected because the frequency the shrinkers are called is now different. This may or may not be a problem but if it is, it'll be because shrinkers are not called enough and some balancing is required. 3. The anon/file reclaim ratio may be affected. Pages about to be dirtied are distributed between zones and the fair zone allocation policy used to do something very similar for anon. The distribution is now different but not necessarily in any way that matters but it's still worth bearing in mind. VM statistic counters for reclaim decisions are zone-based. If the kernel is to reclaim on a per-node basis then we need to track per-node statistics but there is no infrastructure for that. The most notable change is that the old node_page_state is renamed to sum_zone_node_page_state. The new node_page_state takes a pglist_data and uses per-node stats but none exist yet. There is some renaming such as vm_stat to vm_zone_stat and the addition of vm_node_stat and the renaming of mod_state to mod_zone_state. Otherwise, this is mostly a mechanical patch with no functional change. There is a lot of similarity between the node and zone helpers which is unfortunate but there was no obvious way of reusing the code and maintaining type safety. Link: http://lkml.kernel.org/r/1467970510-21195-2-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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65c45377 |
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26-Jul-2016 |
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> |
mm, rmap: account shmem thp pages Let's add ShmemHugePages and ShmemPmdMapped fields into meminfo and smaps. It indicates how many times we allocate and map shmem THP. NR_ANON_TRANSPARENT_HUGEPAGES is renamed to NR_ANON_THPS. Link: http://lkml.kernel.org/r/1466021202-61880-27-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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91537fee |
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26-Jul-2016 |
Minchan Kim <minchan@kernel.org> |
mm: add NR_ZSMALLOC to vmstat zram is very popular for some of the embedded world (e.g., TV, mobile phones). On those system, zsmalloc's consumed memory size is never trivial (one of example from real product system, total memory: 800M, zsmalloc consumed: 150M), so we have used this out of tree patch to monitor system memory behavior via /proc/vmstat. With zsmalloc in vmstat, it helps in tracking down system behavior due to memory usage. [minchan@kernel.org: zsmalloc: follow up zsmalloc vmstat] Link: http://lkml.kernel.org/r/20160607091737.GC23435@bbox [akpm@linux-foundation.org: fix build with CONFIG_ZSMALLOC=m] Link: http://lkml.kernel.org/r/1464919731-13255-1-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Sangseok Lee <sangseok.lee@lge.com> Cc: Chanho Min <chanho.min@lge.com> Cc: Chan Gyun Jeong <chan.jeong@lge.com> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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798fd756 |
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26-Jul-2016 |
Vladimir Davydov <vdavydov.dev@gmail.com> |
mm: zap ZONE_OOM_LOCKED Not used since oom_lock was instroduced. Link: http://lkml.kernel.org/r/1464358093-22663-1-git-send-email-vdavydov@virtuozzo.com Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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7c15d9bb |
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19-Jul-2016 |
Laura Abbott <labbott@redhat.com> |
mm: Add is_migrate_cma_page Code such as hardened user copy[1] needs a way to tell if a page is CMA or not. Add is_migrate_cma_page in a similar way to is_migrate_isolate_page. [1]http://article.gmane.org/gmane.linux.kernel.mm/155238 Signed-off-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org>
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0c9ad804 |
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20-May-2016 |
Weijie Yang <weijie.yang@samsung.com> |
mm fix commmets: if SPARSEMEM, pgdata doesn't have page_ext If SPARSEMEM, use page_ext in mem_section if !SPARSEMEM, use page_ext in pgdata Signed-off-by: Weijie Yang <weijie.yang@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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86a294a8 |
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20-May-2016 |
Michal Hocko <mhocko@suse.com> |
mm, oom, compaction: prevent from should_compact_retry looping for ever for costly orders "mm: consider compaction feedback also for costly allocation" has removed the upper bound for the reclaim/compaction retries based on the number of reclaimed pages for costly orders. While this is desirable the patch did miss a mis interaction between reclaim, compaction and the retry logic. The direct reclaim tries to get zones over min watermark while compaction backs off and returns COMPACT_SKIPPED when all zones are below low watermark + 1<<order gap. If we are getting really close to OOM then __compaction_suitable can keep returning COMPACT_SKIPPED a high order request (e.g. hugetlb order-9) while the reclaim is not able to release enough pages to get us over low watermark. The reclaim is still able to make some progress (usually trashing over few remaining pages) so we are not able to break out from the loop. I have seen this happening with the same test described in "mm: consider compaction feedback also for costly allocation" on a swapless system. The original problem got resolved by "vmscan: consider classzone_idx in compaction_ready" but it shows how things might go wrong when we approach the oom event horizont. The reason why compaction requires being over low rather than min watermark is not clear to me. This check was there essentially since 56de7263fcf3 ("mm: compaction: direct compact when a high-order allocation fails"). It is clearly an implementation detail though and we shouldn't pull it into the generic retry logic while we should be able to cope with such eventuality. The only place in should_compact_retry where we retry without any upper bound is for compaction_withdrawn() case. Introduce compaction_zonelist_suitable function which checks the given zonelist and returns true only if there is at least one zone which would would unblock __compaction_suitable if more memory got reclaimed. In this implementation it checks __compaction_suitable with NR_FREE_PAGES plus part of the reclaimable memory as the target for the watermark check. The reclaimable memory is reduced linearly by the allocation order. The idea is that we do not want to reclaim all the remaining memory for a single allocation request just unblock __compaction_suitable which doesn't guarantee we will make a further progress. The new helper is then used if compaction_withdrawn() feedback was provided so we do not retry if there is no outlook for a further progress. !costly requests shouldn't be affected much - e.g. order-2 pages would require to have at least 64kB on the reclaimable LRUs while order-9 would need at least 32M which should be enough to not lock up. [vbabka@suse.cz: fix classzone_idx vs. high_zoneidx usage in compaction_zonelist_suitable] [akpm@linux-foundation.org: fix it for Mel's mm-page_alloc-remove-field-from-alloc_context.patch] Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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0b423ca2 |
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19-May-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, page_alloc: inline pageblock lookup in page free fast paths The function call overhead of get_pfnblock_flags_mask() is measurable in the page free paths. This patch uses an inlined version that is faster. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
c33d6c06 |
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19-May-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, page_alloc: avoid looking up the first zone in a zonelist twice The allocator fast path looks up the first usable zone in a zonelist and then get_page_from_freelist does the same job in the zonelist iterator. This patch preserves the necessary information. 4.6.0-rc2 4.6.0-rc2 fastmark-v1r20 initonce-v1r20 Min alloc-odr0-1 364.00 ( 0.00%) 359.00 ( 1.37%) Min alloc-odr0-2 262.00 ( 0.00%) 260.00 ( 0.76%) Min alloc-odr0-4 214.00 ( 0.00%) 214.00 ( 0.00%) Min alloc-odr0-8 186.00 ( 0.00%) 186.00 ( 0.00%) Min alloc-odr0-16 173.00 ( 0.00%) 173.00 ( 0.00%) Min alloc-odr0-32 165.00 ( 0.00%) 165.00 ( 0.00%) Min alloc-odr0-64 161.00 ( 0.00%) 162.00 ( -0.62%) Min alloc-odr0-128 159.00 ( 0.00%) 161.00 ( -1.26%) Min alloc-odr0-256 168.00 ( 0.00%) 170.00 ( -1.19%) Min alloc-odr0-512 180.00 ( 0.00%) 181.00 ( -0.56%) Min alloc-odr0-1024 190.00 ( 0.00%) 190.00 ( 0.00%) Min alloc-odr0-2048 196.00 ( 0.00%) 196.00 ( 0.00%) Min alloc-odr0-4096 202.00 ( 0.00%) 202.00 ( 0.00%) Min alloc-odr0-8192 206.00 ( 0.00%) 205.00 ( 0.49%) Min alloc-odr0-16384 206.00 ( 0.00%) 205.00 ( 0.49%) The benefit is negligible and the results are within the noise but each cycle counts. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
c603844b |
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19-May-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, page_alloc: convert alloc_flags to unsigned alloc_flags is a bitmask of flags but it is signed which does not necessarily generate the best code depending on the compiler. Even without an impact, it makes more sense that this be unsigned. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
682a3385 |
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19-May-2016 |
Mel Gorman <mgorman@techsingularity.net> |
mm, page_alloc: inline the fast path of the zonelist iterator The page allocator iterates through a zonelist for zones that match the addressing limitations and nodemask of the caller but many allocations will not be restricted. Despite this, there is always functional call overhead which builds up. This patch inlines the optimistic basic case and only calls the iterator function for the complex case. A hindrance was the fact that cpuset_current_mems_allowed is used in the fastpath as the allowed nodemask even though all nodes are allowed on most systems. The patch handles this by only considering cpuset_current_mems_allowed if a cpuset exists. As well as being faster in the fast-path, this removes some junk in the slowpath. The performance difference on a page allocator microbenchmark is; 4.6.0-rc2 4.6.0-rc2 statinline-v1r20 optiter-v1r20 Min alloc-odr0-1 412.00 ( 0.00%) 382.00 ( 7.28%) Min alloc-odr0-2 301.00 ( 0.00%) 282.00 ( 6.31%) Min alloc-odr0-4 247.00 ( 0.00%) 233.00 ( 5.67%) Min alloc-odr0-8 215.00 ( 0.00%) 203.00 ( 5.58%) Min alloc-odr0-16 199.00 ( 0.00%) 188.00 ( 5.53%) Min alloc-odr0-32 191.00 ( 0.00%) 182.00 ( 4.71%) Min alloc-odr0-64 187.00 ( 0.00%) 177.00 ( 5.35%) Min alloc-odr0-128 185.00 ( 0.00%) 175.00 ( 5.41%) Min alloc-odr0-256 193.00 ( 0.00%) 184.00 ( 4.66%) Min alloc-odr0-512 207.00 ( 0.00%) 197.00 ( 4.83%) Min alloc-odr0-1024 213.00 ( 0.00%) 203.00 ( 4.69%) Min alloc-odr0-2048 220.00 ( 0.00%) 209.00 ( 5.00%) Min alloc-odr0-4096 226.00 ( 0.00%) 214.00 ( 5.31%) Min alloc-odr0-8192 229.00 ( 0.00%) 218.00 ( 4.80%) Min alloc-odr0-16384 229.00 ( 0.00%) 219.00 ( 4.37%) perf indicated that next_zones_zonelist disappeared in the profile and __next_zones_zonelist did not appear. This is expected as the micro-benchmark would hit the inlined fast-path every time. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
29f9cb53 |
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19-May-2016 |
Chanho Min <chanho.min@lge.com> |
mm/highmem: simplify is_highmem() is_highmem() can be simplified by use of is_highmem_idx(). This patch removes redundant code and will make it easier to maintain if the zone policy is changed or a new zone is added. (akpm: saves me 25 bytes of text per is_highmem() callsite) Signed-off-by: Chanho Min <chanho.min@lge.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
795ae7a0 |
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17-Mar-2016 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: scale kswapd watermarks in proportion to memory In machines with 140G of memory and enterprise flash storage, we have seen read and write bursts routinely exceed the kswapd watermarks and cause thundering herds in direct reclaim. Unfortunately, the only way to tune kswapd aggressiveness is through adjusting min_free_kbytes - the system's emergency reserves - which is entirely unrelated to the system's latency requirements. In order to get kswapd to maintain a 250M buffer of free memory, the emergency reserves need to be set to 1G. That is a lot of memory wasted for no good reason. On the other hand, it's reasonable to assume that allocation bursts and overall allocation concurrency scale with memory capacity, so it makes sense to make kswapd aggressiveness a function of that as well. Change the kswapd watermark scale factor from the currently fixed 25% of the tunable emergency reserve to a tunable 0.1% of memory. Beyond 1G of memory, this will produce bigger watermark steps than the current formula in default settings. Ensure that the new formula never chooses steps smaller than that, i.e. 25% of the emergency reserve. On a 140G machine, this raises the default watermark steps - the distance between min and low, and low and high - from 16M to 143M. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
698b1b30 |
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17-Mar-2016 |
Vlastimil Babka <vbabka@suse.cz> |
mm, compaction: introduce kcompactd Memory compaction can be currently performed in several contexts: - kswapd balancing a zone after a high-order allocation failure - direct compaction to satisfy a high-order allocation, including THP page fault attemps - khugepaged trying to collapse a hugepage - manually from /proc The purpose of compaction is two-fold. The obvious purpose is to satisfy a (pending or future) high-order allocation, and is easy to evaluate. The other purpose is to keep overal memory fragmentation low and help the anti-fragmentation mechanism. The success wrt the latter purpose is more The current situation wrt the purposes has a few drawbacks: - compaction is invoked only when a high-order page or hugepage is not available (or manually). This might be too late for the purposes of keeping memory fragmentation low. - direct compaction increases latency of allocations. Again, it would be better if compaction was performed asynchronously to keep fragmentation low, before the allocation itself comes. - (a special case of the previous) the cost of compaction during THP page faults can easily offset the benefits of THP. - kswapd compaction appears to be complex, fragile and not working in some scenarios. It could also end up compacting for a high-order allocation request when it should be reclaiming memory for a later order-0 request. To improve the situation, we should be able to benefit from an equivalent of kswapd, but for compaction - i.e. a background thread which responds to fragmentation and the need for high-order allocations (including hugepages) somewhat proactively. One possibility is to extend the responsibilities of kswapd, which could however complicate its design too much. It should be better to let kswapd handle reclaim, as order-0 allocations are often more critical than high-order ones. Another possibility is to extend khugepaged, but this kthread is a single instance and tied to THP configs. This patch goes with the option of a new set of per-node kthreads called kcompactd, and lays the foundations, without introducing any new tunables. The lifecycle mimics kswapd kthreads, including the memory hotplug hooks. For compaction, kcompactd uses the standard compaction_suitable() and ompact_finished() criteria and the deferred compaction functionality. Unlike direct compaction, it uses only sync compaction, as there's no allocation latency to minimize. This patch doesn't yet add a call to wakeup_kcompactd. The kswapd compact/reclaim loop for high-order pages will be replaced by waking up kcompactd in the next patch with the description of what's wrong with the old approach. Waking up of the kcompactd threads is also tied to kswapd activity and follows these rules: - we don't want to affect any fastpaths, so wake up kcompactd only from the slowpath, as it's done for kswapd - if kswapd is doing reclaim, it's more important than compaction, so don't invoke kcompactd until kswapd goes to sleep - the target order used for kswapd is passed to kcompactd Future possible future uses for kcompactd include the ability to wake up kcompactd on demand in special situations, such as when hugepages are not available (currently not done due to __GFP_NO_KSWAPD) or when a fragmentation event (i.e. __rmqueue_fallback()) occurs. It's also possible to perform periodic compaction with kcompactd. [arnd@arndb.de: fix build errors with kcompactd] [paul.gortmaker@windriver.com: don't use modular references for non modular code] Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: David Rientjes <rientjes@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
7cf91a98 |
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15-Mar-2016 |
Joonsoo Kim <iamjoonsoo.kim@lge.com> |
mm/compaction: speed up pageblock_pfn_to_page() when zone is contiguous There is a performance drop report due to hugepage allocation and in there half of cpu time are spent on pageblock_pfn_to_page() in compaction [1]. In that workload, compaction is triggered to make hugepage but most of pageblocks are un-available for compaction due to pageblock type and skip bit so compaction usually fails. Most costly operations in this case is to find valid pageblock while scanning whole zone range. To check if pageblock is valid to compact, valid pfn within pageblock is required and we can obtain it by calling pageblock_pfn_to_page(). This function checks whether pageblock is in a single zone and return valid pfn if possible. Problem is that we need to check it every time before scanning pageblock even if we re-visit it and this turns out to be very expensive in this workload. Although we have no way to skip this pageblock check in the system where hole exists at arbitrary position, we can use cached value for zone continuity and just do pfn_to_page() in the system where hole doesn't exist. This optimization considerably speeds up in above workload. Before vs After Max: 1096 MB/s vs 1325 MB/s Min: 635 MB/s 1015 MB/s Avg: 899 MB/s 1194 MB/s Avg is improved by roughly 30% [2]. [1]: http://www.spinics.net/lists/linux-mm/msg97378.html [2]: https://lkml.org/lkml/2015/12/9/23 [akpm@linux-foundation.org: don't forget to restore zone->contiguous on error path, per Vlastimil] Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Reported-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Aaron Lu <aaron.lu@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
23047a96 |
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15-Mar-2016 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: workingset: per-cgroup cache thrash detection Cache thrash detection (see a528910e12ec "mm: thrash detection-based file cache sizing" for details) currently only works on the system level, not inside cgroups. Worse, as the refaults are compared to the global number of active cache, cgroups might wrongfully get all their refaults activated when their pages are hotter than those of others. Move the refault machinery from the zone to the lruvec, and then tag eviction entries with the memcg ID. This makes the thrash detection work correctly inside cgroups. [sergey.senozhatsky@gmail.com: do not return from workingset_activation() with locked rcu and page] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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60f30350 |
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15-Mar-2016 |
Vlastimil Babka <vbabka@suse.cz> |
mm, page_owner: print migratetype of page and pageblock, symbolic flags The information in /sys/kernel/debug/page_owner includes the migratetype of the pageblock the page belongs to. This is also checked against the page's migratetype (as declared by gfp_flags during its allocation), and the page is reported as Fallback if its migratetype differs from the pageblock's one. t This is somewhat misleading because in fact fallback allocation is not the only reason why these two can differ. It also doesn't direcly provide the page's migratetype, although it's possible to derive that from the gfp_flags. It's arguably better to print both page and pageblock's migratetype and leave the interpretation to the consumer than to suggest fallback allocation as the only possible reason. While at it, we can print the migratetypes as string the same way as /proc/pagetypeinfo does, as some of the numeric values depend on kernel configuration. For that, this patch moves the migratetype_names array from #ifdef CONFIG_PROC_FS part of mm/vmstat.c to mm/page_alloc.c and exports it. With the new format strings for flags, we can now also provide symbolic page and gfp flags in the /sys/kernel/debug/page_owner file. This replaces the positional printing of page flags as single letters, which might have looked nicer, but was limited to a subset of flags, and required the user to remember the letters. Example page_owner entry after the patch: Page allocated via order 0, mask 0x24213ca(GFP_HIGHUSER_MOVABLE|__GFP_COLD|__GFP_NOWARN|__GFP_NORETRY) PFN 520 type Movable Block 1 type Movable Flags 0xfffff8001006c(referenced|uptodate|lru|active|mappedtodisk) [<ffffffff811682c4>] __alloc_pages_nodemask+0x134/0x230 [<ffffffff811b4058>] alloc_pages_current+0x88/0x120 [<ffffffff8115e386>] __page_cache_alloc+0xe6/0x120 [<ffffffff8116ba6c>] __do_page_cache_readahead+0xdc/0x240 [<ffffffff8116bd05>] ondemand_readahead+0x135/0x260 [<ffffffff8116bfb1>] page_cache_sync_readahead+0x31/0x50 [<ffffffff81160523>] generic_file_read_iter+0x453/0x760 [<ffffffff811e0d57>] __vfs_read+0xa7/0xd0 Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a3d0a918 |
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02-Feb-2016 |
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> |
thp: make split_queue per-node Andrea Arcangeli suggested to make split queue per-node to improve scalability. Let's do it. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Suggested-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a8d01437 |
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14-Jan-2016 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: page_alloc: generalize the dirty balance reserve The dirty balance reserve that dirty throttling has to consider is merely memory not available to userspace allocations. There is nothing writeback-specific about it. Generalize the name so that it's reusable outside of that context. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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5b80287a |
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14-Jan-2016 |
Yaowei Bai <baiyaowei@cmss.chinamobile.com> |
mm/mmzone.c: memmap_valid_within() can be boolean Make memmap_valid_within return bool due to this particular function only using either one or zero as its return value. No functional change. Signed-off-by: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c00eb15a |
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14-Jan-2016 |
Yaowei Bai <baiyaowei@cmss.chinamobile.com> |
mm/zonelist: enumerate zonelists array index Hardcoding index to zonelists array in gfp_zonelist() is not a good idea, let's enumerate it to improve readability. No functional change. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix CONFIG_NUMA=n build] [n-horiguchi@ah.jp.nec.com: fix warning in comparing enumerator] Signed-off-by: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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06640290 |
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14-Jan-2016 |
Yaowei Bai <baiyaowei@cmss.chinamobile.com> |
include/linux/mmzone.h: remove unused is_unevictable_lru() Since commit a0b8cab3b9b2 ("mm: remove lru parameter from __pagevec_lru_add and remove parts of pagevec API") there's no user of this function anymore, so remove it. Signed-off-by: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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89903327 |
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06-Nov-2015 |
Andrew Morton <akpm@linux-foundation.org> |
include/linux/mmzone.h: reflow comment Someone has an 86 column display. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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0aaa29a5 |
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06-Nov-2015 |
Mel Gorman <mgorman@techsingularity.net> |
mm, page_alloc: reserve pageblocks for high-order atomic allocations on demand High-order watermark checking exists for two reasons -- kswapd high-order awareness and protection for high-order atomic requests. Historically the kernel depended on MIGRATE_RESERVE to preserve min_free_kbytes as high-order free pages for as long as possible. This patch introduces MIGRATE_HIGHATOMIC that reserves pageblocks for high-order atomic allocations on demand and avoids using those blocks for order-0 allocations. This is more flexible and reliable than MIGRATE_RESERVE was. A MIGRATE_HIGHORDER pageblock is created when an atomic high-order allocation request steals a pageblock but limits the total number to 1% of the zone. Callers that speculatively abuse atomic allocations for long-lived high-order allocations to access the reserve will quickly fail. Note that SLUB is currently not such an abuser as it reclaims at least once. It is possible that the pageblock stolen has few suitable high-order pages and will need to steal again in the near future but there would need to be strong justification to search all pageblocks for an ideal candidate. The pageblocks are unreserved if an allocation fails after a direct reclaim attempt. The watermark checks account for the reserved pageblocks when the allocation request is not a high-order atomic allocation. The reserved pageblocks can not be used for order-0 allocations. This may allow temporary wastage until a failed reclaim reassigns the pageblock. This is deliberate as the intent of the reservation is to satisfy a limited number of atomic high-order short-lived requests if the system requires them. The stutter benchmark was used to evaluate this but while it was running there was a systemtap script that randomly allocated between 1 high-order page and 12.5% of memory's worth of order-3 pages using GFP_ATOMIC. This is much larger than the potential reserve and it does not attempt to be realistic. It is intended to stress random high-order allocations from an unknown source, show that there is a reduction in failures without introducing an anomaly where atomic allocations are more reliable than regular allocations. The amount of memory reserved varied throughout the workload as reserves were created and reclaimed under memory pressure. The allocation failures once the workload warmed up were as follows; 4.2-rc5-vanilla 70% 4.2-rc5-atomic-reserve 56% The failure rate was also measured while building multiple kernels. The failure rate was 14% but is 6% with this patch applied. Overall, this is a small reduction but the reserves are small relative to the number of allocation requests. In early versions of the patch, the failure rate reduced by a much larger amount but that required much larger reserves and perversely made atomic allocations seem more reliable than regular allocations. [yalin.wang2010@gmail.com: fix redundant check and a memory leak] Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: yalin wang <yalin.wang2010@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
974a786e |
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06-Nov-2015 |
Mel Gorman <mgorman@techsingularity.net> |
mm, page_alloc: remove MIGRATE_RESERVE MIGRATE_RESERVE preserves an old property of the buddy allocator that existed prior to fragmentation avoidance -- min_free_kbytes worth of pages tended to remain contiguous until the only alternative was to fail the allocation. At the time it was discovered that high-order atomic allocations relied on this property so MIGRATE_RESERVE was introduced. A later patch will introduce an alternative MIGRATE_HIGHATOMIC so this patch deletes MIGRATE_RESERVE and supporting code so it'll be easier to review. Note that this patch in isolation may look like a false regression if someone was bisecting high-order atomic allocation failures. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f77cf4e4 |
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06-Nov-2015 |
Mel Gorman <mgorman@techsingularity.net> |
mm, page_alloc: delete the zonelist_cache The zonelist cache (zlc) was introduced to skip over zones that were recently known to be full. This avoided expensive operations such as the cpuset checks, watermark calculations and zone_reclaim. The situation today is different and the complexity of zlc is harder to justify. 1) The cpuset checks are no-ops unless a cpuset is active and in general are a lot cheaper. 2) zone_reclaim is now disabled by default and I suspect that was a large source of the cost that zlc wanted to avoid. When it is enabled, it's known to be a major source of stalling when nodes fill up and it's unwise to hit every other user with the overhead. 3) Watermark checks are expensive to calculate for high-order allocation requests. Later patches in this series will reduce the cost of the watermark checking. 4) The most important issue is that in the current implementation it is possible for a failed THP allocation to mark a zone full for order-0 allocations and cause a fallback to remote nodes. The last issue could be addressed with additional complexity but as the benefit of zlc is questionable, it is better to remove it. If stalls due to zone_reclaim are ever reported then an alternative would be to introduce deferring logic based on a timeout inside zone_reclaim itself and leave the page allocator fast paths alone. The impact on page-allocator microbenchmarks is negligible as they don't hit the paths where the zlc comes into play. Most page-reclaim related workloads showed no noticeable difference as a result of the removal. The impact was noticeable in a workload called "stutter". One part uses a lot of anonymous memory, a second measures mmap latency and a third copies a large file. In an ideal world the latency application would not notice the mmap latency. On a 2-node machine the results of this patch are stutter 4.3.0-rc1 4.3.0-rc1 baseline nozlc-v4 Min mmap 20.9243 ( 0.00%) 20.7716 ( 0.73%) 1st-qrtle mmap 22.0612 ( 0.00%) 22.0680 ( -0.03%) 2nd-qrtle mmap 22.3291 ( 0.00%) 22.3809 ( -0.23%) 3rd-qrtle mmap 25.2244 ( 0.00%) 25.2396 ( -0.06%) Max-90% mmap 48.0995 ( 0.00%) 28.3713 ( 41.02%) Max-93% mmap 52.5557 ( 0.00%) 36.0170 ( 31.47%) Max-95% mmap 55.8173 ( 0.00%) 47.3163 ( 15.23%) Max-99% mmap 67.3781 ( 0.00%) 70.1140 ( -4.06%) Max mmap 24447.6375 ( 0.00%) 12915.1356 ( 47.17%) Mean mmap 33.7883 ( 0.00%) 27.7944 ( 17.74%) Best99%Mean mmap 27.7825 ( 0.00%) 25.2767 ( 9.02%) Best95%Mean mmap 26.3912 ( 0.00%) 23.7994 ( 9.82%) Best90%Mean mmap 24.9886 ( 0.00%) 23.2251 ( 7.06%) Best50%Mean mmap 22.0157 ( 0.00%) 22.0261 ( -0.05%) Best10%Mean mmap 21.6705 ( 0.00%) 21.6083 ( 0.29%) Best5%Mean mmap 21.5581 ( 0.00%) 21.4611 ( 0.45%) Best1%Mean mmap 21.3079 ( 0.00%) 21.1631 ( 0.68%) Note that the maximum stall latency went from 24 seconds to 12 which is still bad but an improvement. The milage varies considerably 2-node machine on an earlier test went from 494 seconds to 47 seconds and a 4-node machine that tested an earlier version of this patch went from a worst case stall time of 6 seconds to 67ms. The nature of the benchmark is inherently unpredictable as it is hammering the system and the milage will vary between machines. There is a secondary impact with potentially more direct reclaim because zones are now being considered instead of being skipped by zlc. In this particular test run it did not occur so will not be described. However, in at least one test the following was observed 1. Direct reclaim rates were higher. This was likely due to direct reclaim being entered instead of the zlc disabling a zone and busy looping. Busy looping may have the effect of allowing kswapd to make more progress and in some cases may be better overall. If this is found then the correct action is to put direct reclaimers to sleep on a waitqueue and allow kswapd make forward progress. Busy looping on the zlc is even worse than when the allocator used to blindly call congestion_wait(). 2. There was higher swap activity as direct reclaim was active. 3. Direct reclaim efficiency was lower. This is related to 1 as more scanning activity also encountered more pages that could not be immediately reclaimed In that case, the direct page scan and reclaim rates are noticeable but it is not considered a problem for a few reasons 1. The test is primarily concerned with latency. The mmap attempts are also faulted which means there are THP allocation requests. The ZLC could cause zones to be disabled causing the process to busy loop instead of reclaiming. This looks like elevated direct reclaim activity but it's the correct action to take based on what processes requested. 2. The test hammers reclaim and compaction heavily. The number of successful THP faults is highly variable but affects the reclaim stats. It's not a realistic or reasonable measure of page reclaim activity. 3. No other page-reclaim intensive workload that was tested showed a problem. 4. If a workload is identified that benefitted from the busy looping then it should be fixed by having direct reclaimers sleep on a wait queue until woken by kswapd instead of busy looping. We had this class of problem before when congestion_waits() with a fixed timeout was a brain damaged decision but happened to benefit some workloads. If a workload is identified that relied on the zlc to busy loop then it should be fixed correctly and have a direct reclaimer sleep on a waitqueue until woken by kswapd. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Christoph Lameter <cl@linux.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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016c13da |
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06-Nov-2015 |
Mel Gorman <mgorman@techsingularity.net> |
mm, page_alloc: use masks and shifts when converting GFP flags to migrate types This patch redefines which GFP bits are used for specifying mobility and the order of the migrate types. Once redefined it's possible to convert GFP flags to a migrate type with a simple mask and shift. The only downside is that readers of OOM kill messages and allocation failures may have been used to the existing values but scripts/gfp-translate will help. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e2b19197 |
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06-Nov-2015 |
Mel Gorman <mgorman@techsingularity.net> |
mm, page_alloc: remove unnecessary parameter from zone_watermark_ok_safe Overall, the intent of this series is to remove the zonelist cache which was introduced to avoid high overhead in the page allocator. Once this is done, it is necessary to reduce the cost of watermark checks. The series starts with minor micro-optimisations. Next it notes that GFP flags that affect watermark checks are abused. __GFP_WAIT historically identified callers that could not sleep and could access reserves. This was later abused to identify callers that simply prefer to avoid sleeping and have other options. A patch distinguishes between atomic callers, high-priority callers and those that simply wish to avoid sleep. The zonelist cache has been around for a long time but it is of dubious merit with a lot of complexity and some issues that are explained. The most important issue is that a failed THP allocation can cause a zone to be treated as "full". This potentially causes unnecessary stalls, reclaim activity or remote fallbacks. The issues could be fixed but it's not worth it. The series places a small number of other micro-optimisations on top before examining GFP flags watermarks. High-order watermarks enforcement can cause high-order allocations to fail even though pages are free. The watermark checks both protect high-order atomic allocations and make kswapd aware of high-order pages but there is a much better way that can be handled using migrate types. This series uses page grouping by mobility to reserve pageblocks for high-order allocations with the size of the reservation depending on demand. kswapd awareness is maintained by examining the free lists. By patch 12 in this series, there are no high-order watermark checks while preserving the properties that motivated the introduction of the watermark checks. This patch (of 10): No user of zone_watermark_ok_safe() specifies alloc_flags. This patch removes the unnecessary parameter. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Christoph Lameter <cl@linux.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b171e409 |
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05-Nov-2015 |
Yaowei Bai <bywxiaobai@163.com> |
mm/page_alloc: remove unused parameter in init_currently_empty_zone() Commit a2f3aa025766 ("[PATCH] Fix sparsemem on Cell") fixed an oops experienced on the Cell architecture when init-time functions, early_*(), are called at runtime by introducing an 'enum memmap_context' parameter to memmap_init_zone() and init_currently_empty_zone(). This parameter is intended to be used to tell whether the call of these two functions is being made on behalf of a hotplug event, or happening at boot-time. However, init_currently_empty_zone() does not use this parameter at all, so remove it. Signed-off-by: Yaowei Bai <bywxiaobai@163.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4e6dab42 |
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04-Sep-2015 |
minkyung88.kim <minkyung88.kim@lge.com> |
mm: remove struct node_active_region struct node_active_region is not used anymore. Remove it. Signed-off-by: minkyung88.kim <minkyung88.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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033fbae9 |
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09-Aug-2015 |
Dan Williams <dan.j.williams@intel.com> |
mm: ZONE_DEVICE for "device memory" While pmem is usable as a block device or via DAX mappings to userspace there are several usage scenarios that can not target pmem due to its lack of struct page coverage. In preparation for "hot plugging" pmem into the vmemmap add ZONE_DEVICE as a new zone to tag these pages separately from the ones that are subject to standard page allocations. Importantly "device memory" can be removed at will by userspace unbinding the driver of the device. Having a separate zone prevents allocation and otherwise marks these pages that are distinct from typical uniform memory. Device memory has different lifetime and performance characteristics than RAM. However, since we have run out of ZONES_SHIFT bits this functionality currently depends on sacrificing ZONE_DMA. Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Jerome Glisse <j.glisse@gmail.com> [hch: various simplifications in the arch interface] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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3a80a7fa |
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30-Jun-2015 |
Mel Gorman <mgorman@suse.de> |
mm: meminit: initialise a subset of struct pages if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set This patch initalises all low memory struct pages and 2G of the highest zone on each node during memory initialisation if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set. That config option cannot be set but will be available in a later patch. Parallel initialisation of struct page depends on some features from memory hotplug and it is necessary to alter alter section annotations. Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Nate Zimmer <nzimmer@sgi.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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75a592a4 |
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30-Jun-2015 |
Mel Gorman <mgorman@suse.de> |
mm: meminit: inline some helper functions early_pfn_in_nid() and meminit_pfn_in_nid() are small functions that are unnecessarily visible outside memory initialisation. As well as unnecessary visibility, it's unnecessary function call overhead when initialising pages. This patch moves the helpers inline. [akpm@linux-foundation.org: fix build] [mhocko@suse.cz: fix build] Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Nate Zimmer <nzimmer@sgi.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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8a942fde |
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30-Jun-2015 |
Mel Gorman <mgorman@suse.de> |
mm: meminit: make __early_pfn_to_nid SMP-safe and introduce meminit_pfn_in_nid __early_pfn_to_nid() use static variables to cache recent lookups as memblock lookups are very expensive but it assumes that memory initialisation is single-threaded. Parallel initialisation of struct pages will break that assumption so this patch makes __early_pfn_to_nid() SMP-safe by requiring the caller to cache recent search information. early_pfn_to_nid() keeps the same interface but is only safe to use early in boot due to the use of a global static variable. meminit_pfn_in_nid() is an SMP-safe version that callers must maintain their own state for. Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Nate Zimmer <nzimmer@sgi.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d7e4a2ea |
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15-Apr-2015 |
Zhang Zhen <zhenzhang.zhang@huawei.com> |
mm: refactor zone_movable_is_highmem() All callers of zone_movable_is_highmem are under #ifdef CONFIG_HIGHMEM, so the else branch return 0 is not needed. Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a368ab67 |
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07-Apr-2015 |
Mel Gorman <mgorman@suse.de> |
mm: move zone lock to a different cache line than order-0 free page lists Huang Ying reported the following problem due to commit 3484b2de9499 ("mm: rearrange zone fields into read-only, page alloc, statistics and page reclaim lines") from the Intel performance tests 24b7e5819ad5cbef 3484b2de9499df23c4604a513b ---------------- -------------------------- %stddev %change %stddev \ | \ 152288 \261 0% -46.2% 81911 \261 0% aim7.jobs-per-min 237 \261 0% +85.6% 440 \261 0% aim7.time.elapsed_time 237 \261 0% +85.6% 440 \261 0% aim7.time.elapsed_time.max 25026 \261 0% +70.7% 42712 \261 0% aim7.time.system_time 2186645 \261 5% +32.0% 2885949 \261 4% aim7.time.voluntary_context_switches 4576561 \261 1% +24.9% 5715773 \261 0% aim7.time.involuntary_context_switches The problem is specific to very large machines under stress. It was not reproducible with the machines I had used to justify the original patch because large numbers of CPUs are required. When pressure is high enough, the cache line is bouncing between CPUs trying to acquire the lock and the holder of the lock adjusting free lists. The intention was that the acquirer of the lock would automatically have the cache line holding the free lists but according to Huang, this is not a universal win. One possibility is to move the zone lock to its own cache line but it increases the size of the zone. This patch moves the lock to the other end of the free lists where they do not contend under high pressure. It does mean the page allocator paths now require more cache lines but Huang reports that it restores performance to previous levels on large machines %stddev %change %stddev \ | \ 84568 \261 1% +94.3% 164280 \261 1% aim7.jobs-per-min 2881944 \261 2% -35.1% 1870386 \261 8% aim7.time.voluntary_context_switches 681 \261 1% -3.4% 658 \261 0% aim7.time.user_time 5538139 \261 0% -12.1% 4867884 \261 0% aim7.time.involuntary_context_switches 44174 \261 1% -46.0% 23848 \261 1% aim7.time.system_time 426 \261 1% -48.4% 219 \261 1% aim7.time.elapsed_time 426 \261 1% -48.4% 219 \261 1% aim7.time.elapsed_time.max 468 \261 1% -43.1% 266 \261 2% uptime.boot Signed-off-by: Mel Gorman <mgorman@suse.de> Reported-by: Huang Ying <ying.huang@intel.com> Tested-by: Huang Ying <ying.huang@intel.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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05891fb0 |
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11-Feb-2015 |
Vlastimil Babka <vbabka@suse.cz> |
mm: microoptimize zonelist operations next_zones_zonelist() returns a zoneref pointer, as well as a zone pointer via extra parameter. Since the latter can be trivially obtained by dereferencing the former, the overhead of the extra parameter is unjustified. This patch thus removes the zone parameter from next_zones_zonelist(). Both callers happen to be in the same header file, so it's simple to add the zoneref dereference inline. We save some bytes of code size. add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-105 (-105) function old new delta nr_free_zone_pages 129 115 -14 __alloc_pages_nodemask 2300 2285 -15 get_page_from_freelist 2652 2576 -76 add/remove: 0/0 grow/shrink: 1/0 up/down: 10/0 (10) function old new delta try_to_compact_pages 569 579 +10 Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Minchan Kim <minchan@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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44628d97 |
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11-Feb-2015 |
Baoquan He <bhe@redhat.com> |
mm: fix typo of MIGRATE_RESERVE in comment Found it when I want to jump to the definition of MIGRATE_RESERVE ctags. Signed-off-by: Baoquan He <bhe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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eefa864b |
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12-Dec-2014 |
Joonsoo Kim <iamjoonsoo.kim@lge.com> |
mm/page_ext: resurrect struct page extending code for debugging When we debug something, we'd like to insert some information to every page. For this purpose, we sometimes modify struct page itself. But, this has drawbacks. First, it requires re-compile. This makes us hesitate to use the powerful debug feature so development process is slowed down. And, second, sometimes it is impossible to rebuild the kernel due to third party module dependency. At third, system behaviour would be largely different after re-compile, because it changes size of struct page greatly and this structure is accessed by every part of kernel. Keeping this as it is would be better to reproduce errornous situation. This feature is intended to overcome above mentioned problems. This feature allocates memory for extended data per page in certain place rather than the struct page itself. This memory can be accessed by the accessor functions provided by this code. During the boot process, it checks whether allocation of huge chunk of memory is needed or not. If not, it avoids allocating memory at all. With this advantage, we can include this feature into the kernel in default and can avoid rebuild and solve related problems. Until now, memcg uses this technique. But, now, memcg decides to embed their variable to struct page itself and it's code to extend struct page has been removed. I'd like to use this code to develop debug feature, so this patch resurrect it. To help these things to work well, this patch introduces two callbacks for clients. One is the need callback which is mandatory if user wants to avoid useless memory allocation at boot-time. The other is optional, init callback, which is used to do proper initialization after memory is allocated. Detailed explanation about purpose of these functions is in code comment. Please refer it. Others are completely same with previous extension code in memcg. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Dave Hansen <dave@sr71.net> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Jungsoo Son <jungsoo.son@lge.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1306a85a |
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10-Dec-2014 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: embed the memcg pointer directly into struct page Memory cgroups used to have 5 per-page pointers. To allow users to disable that amount of overhead during runtime, those pointers were allocated in a separate array, with a translation layer between them and struct page. There is now only one page pointer remaining: the memcg pointer, that indicates which cgroup the page is associated with when charged. The complexity of runtime allocation and the runtime translation overhead is no longer justified to save that *potential* 0.19% of memory. With CONFIG_SLUB, page->mem_cgroup actually sits in the doubleword padding after the page->private member and doesn't even increase struct page, and then this patch actually saves space. Remaining users that care can still compile their kernels without CONFIG_MEMCG. text data bss dec hex filename 8828345 1725264 983040 11536649 b00909 vmlinux.old 8827425 1725264 966656 11519345 afc571 vmlinux.new [mhocko@suse.cz: update Documentation/cgroups/memory.txt] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Vladimir Davydov <vdavydov@parallels.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Tejun Heo <tj@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ad53f92e |
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13-Nov-2014 |
Joonsoo Kim <iamjoonsoo.kim@lge.com> |
mm/page_alloc: fix incorrect isolation behavior by rechecking migratetype Before describing bugs itself, I first explain definition of freepage. 1. pages on buddy list are counted as freepage. 2. pages on isolate migratetype buddy list are *not* counted as freepage. 3. pages on cma buddy list are counted as CMA freepage, too. Now, I describe problems and related patch. Patch 1: There is race conditions on getting pageblock migratetype that it results in misplacement of freepages on buddy list, incorrect freepage count and un-availability of freepage. Patch 2: Freepages on pcp list could have stale cached information to determine migratetype of buddy list to go. This causes misplacement of freepages on buddy list and incorrect freepage count. Patch 4: Merging between freepages on different migratetype of pageblocks will cause freepages accouting problem. This patch fixes it. Without patchset [3], above problem doesn't happens on my CMA allocation test, because CMA reserved pages aren't used at all. So there is no chance for above race. With patchset [3], I did simple CMA allocation test and get below result: - Virtual machine, 4 cpus, 1024 MB memory, 256 MB CMA reservation - run kernel build (make -j16) on background - 30 times CMA allocation(8MB * 30 = 240MB) attempts in 5 sec interval - Result: more than 5000 freepage count are missed With patchset [3] and this patchset, I found that no freepage count are missed so that I conclude that problems are solved. On my simple memory offlining test, these problems also occur on that environment, too. This patch (of 4): There are two paths to reach core free function of buddy allocator, __free_one_page(), one is free_one_page()->__free_one_page() and the other is free_hot_cold_page()->free_pcppages_bulk()->__free_one_page(). Each paths has race condition causing serious problems. At first, this patch is focused on first type of freepath. And then, following patch will solve the problem in second type of freepath. In the first type of freepath, we got migratetype of freeing page without holding the zone lock, so it could be racy. There are two cases of this race. 1. pages are added to isolate buddy list after restoring orignal migratetype CPU1 CPU2 get migratetype => return MIGRATE_ISOLATE call free_one_page() with MIGRATE_ISOLATE grab the zone lock unisolate pageblock release the zone lock grab the zone lock call __free_one_page() with MIGRATE_ISOLATE freepage go into isolate buddy list, although pageblock is already unisolated This may cause two problems. One is that we can't use this page anymore until next isolation attempt of this pageblock, because freepage is on isolate buddy list. The other is that freepage accouting could be wrong due to merging between different buddy list. Freepages on isolate buddy list aren't counted as freepage, but ones on normal buddy list are counted as freepage. If merge happens, buddy freepage on normal buddy list is inevitably moved to isolate buddy list without any consideration of freepage accouting so it could be incorrect. 2. pages are added to normal buddy list while pageblock is isolated. It is similar with above case. This also may cause two problems. One is that we can't keep these freepages from being allocated. Although this pageblock is isolated, freepage would be added to normal buddy list so that it could be allocated without any restriction. And the other problem is same as case 1, that it, incorrect freepage accouting. This race condition would be prevented by checking migratetype again with holding the zone lock. Because it is somewhat heavy operation and it isn't needed in common case, we want to avoid rechecking as much as possible. So this patch introduce new variable, nr_isolate_pageblock in struct zone to check if there is isolated pageblock. With this, we can avoid to re-check migratetype in common case and do it only if there is isolated pageblock or migratetype is MIGRATE_ISOLATE. This solve above mentioned problems. Changes from v3: Add one more check in free_one_page() that checks whether migratetype is MIGRATE_ISOLATE or not. Without this, abovementioned case 1 could happens. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Michal Nazarewicz <mina86@mina86.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Heesub Shin <heesub.shin@samsung.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Ritesh Harjani <ritesh.list@gmail.com> Cc: Gioh Kim <gioh.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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57054651 |
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09-Oct-2014 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: clean up zone flags Page reclaim tests zone_is_reclaim_dirty(), but the site that actually sets this state does zone_set_flag(zone, ZONE_TAIL_LRU_DIRTY), sending the reader through layers indirection just to track down a simple bit. Remove all zone flag wrappers and just use bitops against zone->flags directly. It's just as readable and the lines are barely any longer. Also rename ZONE_TAIL_LRU_DIRTY to ZONE_DIRTY to match ZONE_WRITEBACK, and remove the zone_flags_t typedef. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4ffeaf35 |
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06-Aug-2014 |
Mel Gorman <mgorman@suse.de> |
mm: page_alloc: reduce cost of the fair zone allocation policy The fair zone allocation policy round-robins allocations between zones within a node to avoid age inversion problems during reclaim. If the first allocation fails, the batch counts are reset and a second attempt made before entering the slow path. One assumption made with this scheme is that batches expire at roughly the same time and the resets each time are justified. This assumption does not hold when zones reach their low watermark as the batches will be consumed at uneven rates. Allocation failure due to watermark depletion result in additional zonelist scans for the reset and another watermark check before hitting the slowpath. On UMA, the benefit is negligible -- around 0.25%. On 4-socket NUMA machine it's variable due to the variability of measuring overhead with the vmstat changes. The system CPU overhead comparison looks like 3.16.0-rc3 3.16.0-rc3 3.16.0-rc3 vanilla vmstat-v5 lowercost-v5 User 746.94 774.56 802.00 System 65336.22 32847.27 40852.33 Elapsed 27553.52 27415.04 27368.46 However it is worth noting that the overall benchmark still completed faster and intuitively it makes sense to take as few passes as possible through the zonelists. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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0d5d823a |
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06-Aug-2014 |
Mel Gorman <mgorman@suse.de> |
mm: move zone->pages_scanned into a vmstat counter zone->pages_scanned is a write-intensive cache line during page reclaim and it's also updated during page free. Move the counter into vmstat to take advantage of the per-cpu updates and do not update it in the free paths unless necessary. On a small UMA machine running tiobench the difference is marginal. On a 4-node machine the overhead is more noticable. Note that automatic NUMA balancing was disabled for this test as otherwise the system CPU overhead is unpredictable. 3.16.0-rc3 3.16.0-rc3 3.16.0-rc3 vanillarearrange-v5 vmstat-v5 User 746.94 759.78 774.56 System 65336.22 58350.98 32847.27 Elapsed 27553.52 27282.02 27415.04 Note that the overhead reduction will vary depending on where exactly pages are allocated and freed. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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3484b2de |
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06-Aug-2014 |
Mel Gorman <mgorman@suse.de> |
mm: rearrange zone fields into read-only, page alloc, statistics and page reclaim lines The arrangement of struct zone has changed over time and now it has reached the point where there is some inappropriate sharing going on. On x86-64 for example o The zone->node field is shared with the zone lock and zone->node is accessed frequently from the page allocator due to the fair zone allocation policy. o span_seqlock is almost never used by shares a line with free_area o Some zone statistics share a cache line with the LRU lock so reclaim-intensive and allocator-intensive workloads can bounce the cache line on a stat update This patch rearranges struct zone to put read-only and read-mostly fields together and then splits the page allocator intensive fields, the zone statistics and the page reclaim intensive fields into their own cache lines. Note that the type of lowmem_reserve changes due to the watermark calculations being signed and avoiding a signed/unsigned conversion there. On the test configuration I used the overall size of struct zone shrunk by one cache line. On smaller machines, this is not likely to be noticable. However, on a 4-node NUMA machine running tiobench the system CPU overhead is reduced by this patch. 3.16.0-rc3 3.16.0-rc3 vanillarearrange-v5r9 User 746.94 759.78 System 65336.22 58350.98 Elapsed 27553.52 27282.02 Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1a4dc5bc |
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06-Aug-2014 |
Wang Nan <wangnan0@huawei.com> |
mem-hotplug: improve zone_movable_is_highmem logic In original code, zone_movable_is_highmem() assumes ZONE_MOVABLE not highmem if CONFIG_HAVE_MEMBLOCK_NODE_MAP is not set. In online_pages, it extracts pages from the previous zone before ZONE_MOVABLE. Which is logically inconsistent: If HAVE_MEMBLOCK_NODE_MAP is turned off but HIGHMEM is on, zone_movable_is_highmem() makes movable zone not highmem, but online_pages() extracts pages from ZONE_HIGHMEM. This inconsistency doesn't cause real problem currently, because all architectures support online_pages also have HAVE_MEMBLOCK_NODE_MAP. However, fixing it makes code clear, and also helps futher coding. Signed-off-by: Wang Nan <wangnan0@huawei.com> Cc: Zhang Zhen <zhangzhen@huawei.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Jiang Liu <liuj97@gmail.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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7aeb09f9 |
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04-Jun-2014 |
Mel Gorman <mgorman@suse.de> |
mm: page_alloc: use unsigned int for order in more places X86 prefers the use of unsigned types for iterators and there is a tendency to mix whether a signed or unsigned type if used for page order. This converts a number of sites in mm/page_alloc.c to use unsigned int for order where possible. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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dc4b0caf |
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04-Jun-2014 |
Mel Gorman <mgorman@suse.de> |
mm: page_alloc: reduce number of times page_to_pfn is called In the free path we calculate page_to_pfn multiple times. Reduce that. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e58469ba |
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04-Jun-2014 |
Mel Gorman <mgorman@suse.de> |
mm: page_alloc: use word-based accesses for get/set pageblock bitmaps The test_bit operations in get/set pageblock flags are expensive. This patch reads the bitmap on a word basis and use shifts and masks to isolate the bits of interest. Similarly masks are used to set a local copy of the bitmap and then use cmpxchg to update the bitmap if there have been no other changes made in parallel. In a test running dd onto tmpfs the overhead of the pageblock-related functions went from 1.27% in profiles to 0.5%. In addition to the performance benefits, this patch closes races that are possible between: a) get_ and set_pageblock_migratetype(), where get_pageblock_migratetype() reads part of the bits before and other part of the bits after set_pageblock_migratetype() has updated them. b) set_pageblock_migratetype() and set_pageblock_skip(), where the non-atomic read-modify-update set bit operation in set_pageblock_skip() will cause lost updates to some bits changed in the set_pageblock_migratetype(). Joonsoo Kim first reported the case a) via code inspection. Vlastimil Babka's testing with a debug patch showed that either a) or b) occurs roughly once per mmtests' stress-highalloc benchmark (although not necessarily in the same pageblock). Furthermore during development of unrelated compaction patches, it was observed that frequent calls to {start,undo}_isolate_page_range() the race occurs several thousands of times and has resulted in NULL pointer dereferences in move_freepages() and free_one_page() in places where free_list[migratetype] is manipulated by e.g. list_move(). Further debugging confirmed that migratetype had invalid value of 6, causing out of bounds access to the free_list array. That confirmed that the race exist, although it may be extremely rare, and currently only fatal where page isolation is performed due to memory hot remove. Races on pageblocks being updated by set_pageblock_migratetype(), where both old and new migratetype are lower MIGRATE_RESERVE, currently cannot result in an invalid value being observed, although theoretically they may still lead to unexpected creation or destruction of MIGRATE_RESERVE pageblocks. Furthermore, things could get suddenly worse when memory isolation is used more, or when new migratetypes are added. After this patch, the race has no longer been observed in testing. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Reported-and-tested-by: Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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35979ef3 |
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04-Jun-2014 |
David Rientjes <rientjes@google.com> |
mm, compaction: add per-zone migration pfn cache for async compaction Each zone has a cached migration scanner pfn for memory compaction so that subsequent calls to memory compaction can start where the previous call left off. Currently, the compaction migration scanner only updates the per-zone cached pfn when pageblocks were not skipped for async compaction. This creates a dependency on calling sync compaction to avoid having subsequent calls to async compaction from scanning an enormous amount of non-MOVABLE pageblocks each time it is called. On large machines, this could be potentially very expensive. This patch adds a per-zone cached migration scanner pfn only for async compaction. It is updated everytime a pageblock has been scanned in its entirety and when no pages from it were successfully isolated. The cached migration scanner pfn for sync compaction is updated only when called for sync compaction. Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Greg Thelen <gthelen@google.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bfc8c901 |
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04-Jun-2014 |
Vladimir Davydov <vdavydov.dev@gmail.com> |
mem-hotplug: implement get/put_online_mems kmem_cache_{create,destroy,shrink} need to get a stable value of cpu/node online mask, because they init/destroy/access per-cpu/node kmem_cache parts, which can be allocated or destroyed on cpu/mem hotplug. To protect against cpu hotplug, these functions use {get,put}_online_cpus. However, they do nothing to synchronize with memory hotplug - taking the slab_mutex does not eliminate the possibility of race as described in patch 2. What we need there is something like get_online_cpus, but for memory. We already have lock_memory_hotplug, which serves for the purpose, but it's a bit of a hammer right now, because it's backed by a mutex. As a result, it imposes some limitations to locking order, which are not desirable, and can't be used just like get_online_cpus. That's why in patch 1 I substitute it with get/put_online_mems, which work exactly like get/put_online_cpus except they block not cpu, but memory hotplug. [ v1 can be found at https://lkml.org/lkml/2014/4/6/68. I NAK'ed it by myself, because it used an rw semaphore for get/put_online_mems, making them dead lock prune. ] This patch (of 2): {un}lock_memory_hotplug, which is used to synchronize against memory hotplug, is currently backed by a mutex, which makes it a bit of a hammer - threads that only want to get a stable value of online nodes mask won't be able to proceed concurrently. Also, it imposes some strong locking ordering rules on it, which narrows down the set of its usage scenarios. This patch introduces get/put_online_mems, which are the same as get/put_online_cpus, but for memory hotplug, i.e. executing a code inside a get/put_online_mems section will guarantee a stable value of online nodes, present pages, etc. lock_memory_hotplug()/unlock_memory_hotplug() are removed altogether. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Toshi Kani <toshi.kani@hp.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: Jiang Liu <liuj97@gmail.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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5f7a75ac |
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04-Jun-2014 |
Mel Gorman <mgorman@suse.de> |
mm: page_alloc: do not cache reclaim distances pgdat->reclaim_nodes tracks if a remote node is allowed to be reclaimed by zone_reclaim due to its distance. As it is expected that zone_reclaim_mode will be rarely enabled it is unreasonable for all machines to take a penalty. Fortunately, the zone_reclaim_mode() path is already slow and it is the path that takes the hit. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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449dd698 |
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03-Apr-2014 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: keep page cache radix tree nodes in check Previously, page cache radix tree nodes were freed after reclaim emptied out their page pointers. But now reclaim stores shadow entries in their place, which are only reclaimed when the inodes themselves are reclaimed. This is problematic for bigger files that are still in use after they have a significant amount of their cache reclaimed, without any of those pages actually refaulting. The shadow entries will just sit there and waste memory. In the worst case, the shadow entries will accumulate until the machine runs out of memory. To get this under control, the VM will track radix tree nodes exclusively containing shadow entries on a per-NUMA node list. Per-NUMA rather than global because we expect the radix tree nodes themselves to be allocated node-locally and we want to reduce cross-node references of otherwise independent cache workloads. A simple shrinker will then reclaim these nodes on memory pressure. A few things need to be stored in the radix tree node to implement the shadow node LRU and allow tree deletions coming from the list: 1. There is no index available that would describe the reverse path from the node up to the tree root, which is needed to perform a deletion. To solve this, encode in each node its offset inside the parent. This can be stored in the unused upper bits of the same member that stores the node's height at no extra space cost. 2. The number of shadow entries needs to be counted in addition to the regular entries, to quickly detect when the node is ready to go to the shadow node LRU list. The current entry count is an unsigned int but the maximum number of entries is 64, so a shadow counter can easily be stored in the unused upper bits. 3. Tree modification needs tree lock and tree root, which are located in the address space, so store an address_space backpointer in the node. The parent pointer of the node is in a union with the 2-word rcu_head, so the backpointer comes at no extra cost as well. 4. The node needs to be linked to an LRU list, which requires a list head inside the node. This does increase the size of the node, but it does not change the number of objects that fit into a slab page. [akpm@linux-foundation.org: export the right function] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Metin Doslu <metin@citusdata.com> Cc: Michel Lespinasse <walken@google.com> Cc: Ozgun Erdogan <ozgun@citusdata.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin <klamm@yandex-team.ru> Cc: Ryan Mallon <rmallon@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a528910e |
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03-Apr-2014 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: thrash detection-based file cache sizing The VM maintains cached filesystem pages on two types of lists. One list holds the pages recently faulted into the cache, the other list holds pages that have been referenced repeatedly on that first list. The idea is to prefer reclaiming young pages over those that have shown to benefit from caching in the past. We call the recently usedbut ultimately was not significantly better than a FIFO policy and still thrashed cache based on eviction speed, rather than actual demand for cache. This patch solves one half of the problem by decoupling the ability to detect working set changes from the inactive list size. By maintaining a history of recently evicted file pages it can detect frequently used pages with an arbitrarily small inactive list size, and subsequently apply pressure on the active list based on actual demand for cache, not just overall eviction speed. Every zone maintains a counter that tracks inactive list aging speed. When a page is evicted, a snapshot of this counter is stored in the now-empty page cache radix tree slot. On refault, the minimum access distance of the page can be assessed, to evaluate whether the page should be part of the active list or not. This fixes the VM's blindness towards working set changes in excess of the inactive list. And it's the foundation to further improve the protection ability and reduce the minimum inactive list size of 50%. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Bob Liu <bob.liu@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Metin Doslu <metin@citusdata.com> Cc: Michel Lespinasse <walken@google.com> Cc: Ozgun Erdogan <ozgun@citusdata.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin <klamm@yandex-team.ru> Cc: Ryan Mallon <rmallon@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e97ca8e5 |
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10-Mar-2014 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: fix GFP_THISNODE callers and clarify GFP_THISNODE is for callers that implement their own clever fallback to remote nodes. It restricts the allocation to the specified node and does not invoke reclaim, assuming that the caller will take care of it when the fallback fails, e.g. through a subsequent allocation request without GFP_THISNODE set. However, many current GFP_THISNODE users only want the node exclusive aspect of the flag, without actually implementing their own fallback or triggering reclaim if necessary. This results in things like page migration failing prematurely even when there is easily reclaimable memory available, unless kswapd happens to be running already or a concurrent allocation attempt triggers the necessary reclaim. Convert all callsites that don't implement their own fallback strategy to __GFP_THISNODE. This restricts the allocation a single node too, but at the same time allows the allocator to enter the slowpath, wake kswapd, and invoke direct reclaim if necessary, to make the allocation happen when memory is full. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Rik van Riel <riel@redhat.com> Cc: Jan Stancek <jstancek@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1c5e9c27 |
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21-Jan-2014 |
Mel Gorman <mgorman@suse.de> |
mm: numa: limit scope of lock for NUMA migrate rate limiting NUMA migrate rate limiting protects a migration counter and window using a lock but in some cases this can be a contended lock. It is not critical that the number of pages be perfect, lost updates are acceptable. Reduce the importance of this lock. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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943dca1a |
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21-Jan-2014 |
Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> |
mm: get rid of unnecessary pageblock scanning in setup_zone_migrate_reserve Yasuaki Ishimatsu reported memory hot-add spent more than 5 _hours_ on 9TB memory machine since onlining memory sections is too slow. And we found out setup_zone_migrate_reserve spent >90% of the time. The problem is, setup_zone_migrate_reserve scans all pageblocks unconditionally, but it is only necessary if the number of reserved block was reduced (i.e. memory hot remove). Moreover, maximum MIGRATE_RESERVE per zone is currently 2. It means that the number of reserved pageblocks is almost always unchanged. This patch adds zone->nr_migrate_reserve_block to maintain the number of MIGRATE_RESERVE pageblocks and it reduces the overhead of setup_zone_migrate_reserve dramatically. The following table shows time of onlining a memory section. Amount of memory | 128GB | 192GB | 256GB| --------------------------------------------- linux-3.12 | 23.9 | 31.4 | 44.5 | This patch | 8.3 | 8.3 | 8.6 | Mel's proposal patch | 10.9 | 19.2 | 31.3 | --------------------------------------------- (millisecond) 128GB : 4 nodes and each node has 32GB of memory 192GB : 6 nodes and each node has 32GB of memory 256GB : 8 nodes and each node has 32GB of memory (*1) Mel proposed his idea by the following threads. https://lkml.org/lkml/2013/10/30/272 [akpm@linux-foundation.org: tweak comment] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Reported-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Tested-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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6e543d57 |
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11-Sep-2013 |
Lisa Du <cldu@marvell.com> |
mm: vmscan: fix do_try_to_free_pages() livelock This patch is based on KOSAKI's work and I add a little more description, please refer https://lkml.org/lkml/2012/6/14/74. Currently, I found system can enter a state that there are lots of free pages in a zone but only order-0 and order-1 pages which means the zone is heavily fragmented, then high order allocation could make direct reclaim path's long stall(ex, 60 seconds) especially in no swap and no compaciton enviroment. This problem happened on v3.4, but it seems issue still lives in current tree, the reason is do_try_to_free_pages enter live lock: kswapd will go to sleep if the zones have been fully scanned and are still not balanced. As kswapd thinks there's little point trying all over again to avoid infinite loop. Instead it changes order from high-order to 0-order because kswapd think order-0 is the most important. Look at 73ce02e9 in detail. If watermarks are ok, kswapd will go back to sleep and may leave zone->all_unreclaimable =3D 0. It assume high-order users can still perform direct reclaim if they wish. Direct reclaim continue to reclaim for a high order which is not a COSTLY_ORDER without oom-killer until kswapd turn on zone->all_unreclaimble= . This is because to avoid too early oom-kill. So it means direct_reclaim depends on kswapd to break this loop. In worst case, direct-reclaim may continue to page reclaim forever when kswapd sleeps forever until someone like watchdog detect and finally kill the process. As described in: http://thread.gmane.org/gmane.linux.kernel.mm/103737 We can't turn on zone->all_unreclaimable from direct reclaim path because direct reclaim path don't take any lock and this way is racy. Thus this patch removes zone->all_unreclaimable field completely and recalculates zone reclaimable state every time. Note: we can't take the idea that direct-reclaim see zone->pages_scanned directly and kswapd continue to use zone->all_unreclaimable. Because, it is racy. commit 929bea7c71 (vmscan: all_unreclaimable() use zone->all_unreclaimable as a name) describes the detail. [akpm@linux-foundation.org: uninline zone_reclaimable_pages() and zone_reclaimable()] Cc: Aaditya Kumar <aaditya.kumar.30@gmail.com> Cc: Ying Han <yinghan@google.com> Cc: Nick Piggin <npiggin@gmail.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux.com> Cc: Bob Liu <lliubbo@gmail.com> Cc: Neil Zhang <zhangwm@marvell.com> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Lisa Du <cldu@marvell.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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81c0a2bb |
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11-Sep-2013 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: page_alloc: fair zone allocator policy Each zone that holds userspace pages of one workload must be aged at a speed proportional to the zone size. Otherwise, the time an individual page gets to stay in memory depends on the zone it happened to be allocated in. Asymmetry in the zone aging creates rather unpredictable aging behavior and results in the wrong pages being reclaimed, activated etc. But exactly this happens right now because of the way the page allocator and kswapd interact. The page allocator uses per-node lists of all zones in the system, ordered by preference, when allocating a new page. When the first iteration does not yield any results, kswapd is woken up and the allocator retries. Due to the way kswapd reclaims zones below the high watermark while a zone can be allocated from when it is above the low watermark, the allocator may keep kswapd running while kswapd reclaim ensures that the page allocator can keep allocating from the first zone in the zonelist for extended periods of time. Meanwhile the other zones rarely see new allocations and thus get aged much slower in comparison. The result is that the occasional page placed in lower zones gets relatively more time in memory, even gets promoted to the active list after its peers have long been evicted. Meanwhile, the bulk of the working set may be thrashing on the preferred zone even though there may be significant amounts of memory available in the lower zones. Even the most basic test -- repeatedly reading a file slightly bigger than memory -- shows how broken the zone aging is. In this scenario, no single page should be able stay in memory long enough to get referenced twice and activated, but activation happens in spades: $ grep active_file /proc/zoneinfo nr_inactive_file 0 nr_active_file 0 nr_inactive_file 0 nr_active_file 8 nr_inactive_file 1582 nr_active_file 11994 $ cat data data data data >/dev/null $ grep active_file /proc/zoneinfo nr_inactive_file 0 nr_active_file 70 nr_inactive_file 258753 nr_active_file 443214 nr_inactive_file 149793 nr_active_file 12021 Fix this with a very simple round robin allocator. Each zone is allowed a batch of allocations that is proportional to the zone's size, after which it is treated as full. The batch counters are reset when all zones have been tried and the allocator enters the slowpath and kicks off kswapd reclaim. Allocation and reclaim is now fairly spread out to all available/allowable zones: $ grep active_file /proc/zoneinfo nr_inactive_file 0 nr_active_file 0 nr_inactive_file 174 nr_active_file 4865 nr_inactive_file 53 nr_active_file 860 $ cat data data data data >/dev/null $ grep active_file /proc/zoneinfo nr_inactive_file 0 nr_active_file 0 nr_inactive_file 666622 nr_active_file 4988 nr_inactive_file 190969 nr_active_file 937 When zone_reclaim_mode is enabled, allocations will now spread out to all zones on the local node, not just the first preferred zone (which on a 4G node might be a tiny Normal zone). Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Paul Bolle <paul.bollee@gmail.com> Cc: Zlatko Calusic <zcalusic@bitsync.net> Tested-by: Kevin Hilman <khilman@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b21fbccd |
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08-Jul-2013 |
Zhang Yanfei <zhangyanfei@cn.fujitsu.com> |
mm: remove unused functions is_{normal_idx, normal, dma32, dma} These functions are nowhere used, so remove them. Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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55878e88 |
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03-Jul-2013 |
Cody P Schafer <cody@linux.vnet.ibm.com> |
sparsemem: add BUILD_BUG_ON when sizeof mem_section is non-power-of-2 Instead of leaving a hidden trap for the next person who comes along and wants to add something to mem_section, add a big fat warning about it needing to be a power-of-2, and insert a BUILD_BUG_ON() in sparse_init() to catch mistakes. Right now non-power-of-2 mem_sections cause a number of WARNs at boot (which don't clearly point to the size of mem_section as an issue), but the system limps on (temporarily, at least). This is based upon Dave Hansen's earlier RFC where he ran into the same issue: "sparsemem: fix boot when SECTIONS_PER_ROOT is not power-of-2" http://lkml.indiana.edu/hypermail/linux/kernel/1205.2/03077.html Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jiang Liu <liuj97@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c3d5f5f0 |
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03-Jul-2013 |
Jiang Liu <liuj97@gmail.com> |
mm: use a dedicated lock to protect totalram_pages and zone->managed_pages Currently lock_memory_hotplug()/unlock_memory_hotplug() are used to protect totalram_pages and zone->managed_pages. Other than the memory hotplug driver, totalram_pages and zone->managed_pages may also be modified at runtime by other drivers, such as Xen balloon, virtio_balloon etc. For those cases, memory hotplug lock is a little too heavy, so introduce a dedicated lock to protect totalram_pages and zone->managed_pages. Now we have a simplified locking rules totalram_pages and zone->managed_pages as: 1) no locking for read accesses because they are unsigned long. 2) no locking for write accesses at boot time in single-threaded context. 3) serialize write accesses at runtime by acquiring the dedicated managed_page_count_lock. Also adjust zone->managed_pages when freeing reserved pages into the buddy system, to keep totalram_pages and zone->managed_pages in consistence. [akpm@linux-foundation.org: don't export adjust_managed_page_count to modules (for now)] Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: <sworddragon2@aol.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: David Howells <dhowells@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Jianguo Wu <wujianguo@huawei.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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114d4b79 |
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03-Jul-2013 |
Cody P Schafer <cody@linux.vnet.ibm.com> |
mmzone: note that node_size_lock should be manipulated via pgdat_resize_lock() Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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72c3b51b |
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03-Jul-2013 |
Cody P Schafer <cody@linux.vnet.ibm.com> |
mm: fix comment referring to non-existent size_seqlock, change to span_seqlock Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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283aba9f |
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03-Jul-2013 |
Mel Gorman <mgorman@suse.de> |
mm: vmscan: block kswapd if it is encountering pages under writeback Historically, kswapd used to congestion_wait() at higher priorities if it was not making forward progress. This made no sense as the failure to make progress could be completely independent of IO. It was later replaced by wait_iff_congested() and removed entirely by commit 258401a6 (mm: don't wait on congested zones in balance_pgdat()) as it was duplicating logic in shrink_inactive_list(). This is problematic. If kswapd encounters many pages under writeback and it continues to scan until it reaches the high watermark then it will quickly skip over the pages under writeback and reclaim clean young pages or push applications out to swap. The use of wait_iff_congested() is not suited to kswapd as it will only stall if the underlying BDI is really congested or a direct reclaimer was unable to write to the underlying BDI. kswapd bypasses the BDI congestion as it sets PF_SWAPWRITE but even if this was taken into account then it would cause direct reclaimers to stall on writeback which is not desirable. This patch sets a ZONE_WRITEBACK flag if direct reclaim or kswapd is encountering too many pages under writeback. If this flag is set and kswapd encounters a PageReclaim page under writeback then it'll assume that the LRU lists are being recycled too quickly before IO can complete and block waiting for some IO to complete. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Tested-by: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d43006d5 |
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03-Jul-2013 |
Mel Gorman <mgorman@suse.de> |
mm: vmscan: have kswapd writeback pages based on dirty pages encountered, not priority Currently kswapd queues dirty pages for writeback if scanning at an elevated priority but the priority kswapd scans at is not related to the number of unqueued dirty encountered. Since commit "mm: vmscan: Flatten kswapd priority loop", the priority is related to the size of the LRU and the zone watermark which is no indication as to whether kswapd should write pages or not. This patch tracks if an excessive number of unqueued dirty pages are being encountered at the end of the LRU. If so, it indicates that dirty pages are being recycled before flusher threads can clean them and flags the zone so that kswapd will start writing pages until the zone is balanced. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Tested-by: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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8761e31c |
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26-Mar-2013 |
Cody P Schafer <cody@linux.vnet.ibm.com> |
mmzone: correct "pags" to "pages" in comment. Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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f9228b20 |
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22-Mar-2013 |
Russ Anderson <rja@sgi.com> |
mm: zone_end_pfn is too small Booting with 32 TBytes memory hits BUG at mm/page_alloc.c:552! (output below). The key hint is "page 4294967296 outside zone". 4294967296 = 0x100000000 (bit 32 is set). The problem is in include/linux/mmzone.h: 530 static inline unsigned zone_end_pfn(const struct zone *zone) 531 { 532 return zone->zone_start_pfn + zone->spanned_pages; 533 } zone_end_pfn is "unsigned" (32 bits). Changing it to "unsigned long" (64 bits) fixes the problem. zone_end_pfn() was added recently in commit 108bcc96ef70 ("mm: add & use zone_end_pfn() and zone_spans_pfn()") Output from the failure. No AGP bridge found page 4294967296 outside zone [ 4294967296 - 4327469056 ] ------------[ cut here ]------------ kernel BUG at mm/page_alloc.c:552! invalid opcode: 0000 [#1] SMP Modules linked in: CPU 0 Pid: 0, comm: swapper Not tainted 3.9.0-rc2.dtp+ #10 RIP: free_one_page+0x382/0x430 Process swapper (pid: 0, threadinfo ffffffff81942000, task ffffffff81955420) Call Trace: __free_pages_ok+0x96/0xb0 __free_pages+0x25/0x50 __free_pages_bootmem+0x8a/0x8c __free_memory_core+0xea/0x131 free_low_memory_core_early+0x4a/0x98 free_all_bootmem+0x45/0x47 mem_init+0x7b/0x14c start_kernel+0x216/0x433 x86_64_start_reservations+0x2a/0x2c x86_64_start_kernel+0x144/0x153 Code: 89 f1 ba 01 00 00 00 31 f6 d3 e2 4c 89 ef e8 66 a4 01 00 e9 2c fe ff ff 0f 0b eb fe 0f 0b 66 66 2e 0f 1f 84 00 00 00 00 00 eb f3 <0f> 0b eb fe 0f 0b 0f 1f 84 00 00 00 00 00 eb f6 0f 0b eb fe 49 Signed-off-by: Russ Anderson <rja@sgi.com> Reported-by: George Beshers <gbeshers@sgi.com> Acked-by: Hedi Berriche <hedi@sgi.com> Cc: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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da3649e1 |
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22-Feb-2013 |
Cody P Schafer <cody@linux.vnet.ibm.com> |
mmzone: add pgdat_{end_pfn,is_empty}() helpers & consolidate. Add pgdat_end_pfn() and pgdat_is_empty() helpers which match the similar zone_*() functions. Change node_end_pfn() to be a wrapper of pgdat_end_pfn(). Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: David Hansen <dave@linux.vnet.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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2a6e3ebe |
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22-Feb-2013 |
Cody P Schafer <cody@linux.vnet.ibm.com> |
mm: add zone_is_empty() and zone_is_initialized() Factoring out these 2 checks makes it more clear what we are actually checking for. Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: David Hansen <dave@linux.vnet.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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108bcc96 |
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22-Feb-2013 |
Cody P Schafer <cody@linux.vnet.ibm.com> |
mm: add & use zone_end_pfn() and zone_spans_pfn() Add 2 helpers (zone_end_pfn() and zone_spans_pfn()) to reduce code duplication. This also switches to using them in compaction (where an additional variable needed to be renamed), page_alloc, vmstat, memory_hotplug, and kmemleak. Note that in compaction.c I avoid calling zone_end_pfn() repeatedly because I expect at some point the sycronization issues with start_pfn & spanned_pages will need fixing, either by actually using the seqlock or clever memory barrier usage. Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: David Hansen <dave@linux.vnet.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bbeae5b0 |
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22-Feb-2013 |
Peter Zijlstra <a.p.zijlstra@chello.nl> |
mm: move page flags layout to separate header This is a preparation patch for moving page->_last_nid into page->flags that moves page flag layout information to a separate header. This patch is necessary because otherwise there would be a circular dependency between mm_types.h and mm.h. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Simon Jeons <simon.jeons@gmail.com> Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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194159fb |
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22-Feb-2013 |
Minchan Kim <minchan@kernel.org> |
mm: remove MIGRATE_ISOLATE check in hotpath Several functions test MIGRATE_ISOLATE and some of those are hotpath but MIGRATE_ISOLATE is used only if we enable CONFIG_MEMORY_ISOLATION(ie, CMA, memory-hotplug and memory-failure) which are not common config option. So let's not add unnecessary overhead and code when we don't enable CONFIG_MEMORY_ISOLATION. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a458431e |
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04-Jan-2013 |
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> |
mm: fix zone_watermark_ok_safe() accounting of isolated pages Commit 702d1a6e0766 ("memory-hotplug: fix kswapd looping forever problem") added an isolated pageblocks counter (nr_pageblock_isolate in struct zone) and used it to adjust free pages counter in zone_watermark_ok_safe() to prevent kswapd looping forever problem. Then later, commit 2139cbe627b8 ("cma: fix counting of isolated pages") fixed accounting of isolated pages in global free pages counter. It made the previous zone_watermark_ok_safe() fix unnecessary and potentially harmful (cause now isolated pages may be accounted twice making free pages counter incorrect). This patch removes the special isolated pageblocks counter altogether which fixes zone_watermark_ok_safe() free pages check. Reported-by: Tomasz Stanislawski <t.stanislaws@samsung.com> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Cc: Minchan Kim <minchan@kernel.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Aaditya Kumar <aaditya.kumar.30@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
9feedc9d |
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12-Dec-2012 |
Jiang Liu <liuj97@gmail.com> |
mm: introduce new field "managed_pages" to struct zone Currently a zone's present_pages is calcuated as below, which is inaccurate and may cause trouble to memory hotplug. spanned_pages - absent_pages - memmap_pages - dma_reserve. During fixing bugs caused by inaccurate zone->present_pages, we found zone->present_pages has been abused. The field zone->present_pages may have different meanings in different contexts: 1) pages existing in a zone. 2) pages managed by the buddy system. For more discussions about the issue, please refer to: http://lkml.org/lkml/2012/11/5/866 https://patchwork.kernel.org/patch/1346751/ This patchset tries to introduce a new field named "managed_pages" to struct zone, which counts "pages managed by the buddy system". And revert zone->present_pages to count "physical pages existing in a zone", which also keep in consistence with pgdat->node_present_pages. We will set an initial value for zone->managed_pages in function free_area_init_core() and will adjust it later if the initial value is inaccurate. For DMA/normal zones, the initial value is set to: (spanned_pages - absent_pages - memmap_pages - dma_reserve) Later zone->managed_pages will be adjusted to the accurate value when the bootmem allocator frees all free pages to the buddy system in function free_all_bootmem_node() and free_all_bootmem(). The bootmem allocator doesn't touch highmem pages, so highmem zones' managed_pages is set to the accurate value "spanned_pages - absent_pages" in function free_area_init_core() and won't be updated anymore. This patch also adds a new field "managed_pages" to /proc/zoneinfo and sysrq showmem. [akpm@linux-foundation.org: small comment tweaks] Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Maciej Rutecki <maciej.rutecki@gmail.com> Tested-by: Chris Clayton <chris2553@googlemail.com> Cc: "Rafael J . Wysocki" <rjw@sisk.pl> Cc: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan@kernel.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Jianguo Wu <wujianguo@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
bc357f43 |
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11-Dec-2012 |
Marek Szyprowski <m.szyprowski@samsung.com> |
mm: cma: remove watermark hacks Commits 2139cbe627b8 ("cma: fix counting of isolated pages") and d95ea5d18e69 ("cma: fix watermark checking") introduced a reliable method of free page accounting when memory is being allocated from CMA regions, so the workaround introduced earlier by commit 49f223a9cd96 ("mm: trigger page reclaim in alloc_contig_range() to stabilise watermarks") can be finally removed. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Mel Gorman <mel@csn.ul.ie> Acked-by: Michal Nazarewicz <mina86@mina86.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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8177a420 |
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23-Mar-2012 |
Andrea Arcangeli <aarcange@redhat.com> |
mm: numa: Structures for Migrate On Fault per NUMA migration rate limiting This defines the per-node data used by Migrate On Fault in order to rate limit the migration. The rate limiting is applied independently to each destination node. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de>
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bea8c150 |
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16-Nov-2012 |
Hugh Dickins <hughd@google.com> |
memcg: fix hotplugged memory zone oops When MEMCG is configured on (even when it's disabled by boot option), when adding or removing a page to/from its lru list, the zone pointer used for stats updates is nowadays taken from the struct lruvec. (On many configurations, calculating zone from page is slower.) But we have no code to update all the lruvecs (per zone, per memcg) when a memory node is hotadded. Here's an extract from the oops which results when running numactl to bind a program to a newly onlined node: BUG: unable to handle kernel NULL pointer dereference at 0000000000000f60 IP: __mod_zone_page_state+0x9/0x60 Pid: 1219, comm: numactl Not tainted 3.6.0-rc5+ #180 Bochs Bochs Process numactl (pid: 1219, threadinfo ffff880039abc000, task ffff8800383c4ce0) Call Trace: __pagevec_lru_add_fn+0xdf/0x140 pagevec_lru_move_fn+0xb1/0x100 __pagevec_lru_add+0x1c/0x30 lru_add_drain_cpu+0xa3/0x130 lru_add_drain+0x2f/0x40 ... The natural solution might be to use a memcg callback whenever memory is hotadded; but that solution has not been scoped out, and it happens that we do have an easy location at which to update lruvec->zone. The lruvec pointer is discovered either by mem_cgroup_zone_lruvec() or by mem_cgroup_page_lruvec(), and both of those do know the right zone. So check and set lruvec->zone in those; and remove the inadequate attempt to set lruvec->zone from lruvec_init(), which is called before NODE_DATA(node) has been allocated in such cases. Ah, there was one exceptionr. For no particularly good reason, mem_cgroup_force_empty_list() has its own code for deciding lruvec. Change it to use the standard mem_cgroup_zone_lruvec() and mem_cgroup_get_lru_size() too. In fact it was already safe against such an oops (the lru lists in danger could only be empty), but we're better proofed against future changes this way. I've marked this for stable (3.6) since we introduced the problem in 3.5 (now closed to stable); but I have no idea if this is the only fix needed to get memory hotadd working with memcg in 3.6, and received no answer when I enquired twice before. Reported-by: Tang Chen <tangchen@cn.fujitsu.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e46a2879 |
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08-Oct-2012 |
Minchan Kim <minchan@kernel.org> |
CMA: migrate mlocked pages Presently CMA cannot migrate mlocked pages so it ends up failing to allocate contiguous memory space. This patch makes mlocked pages be migrated out. Of course, it can affect realtime processes but in CMA usecase, contiguous memory allocation failing is far worse than access latency to an mlocked page being variable while CMA is running. If someone wants to make the system realtime, he shouldn't enable CMA because stalls can still happen at random times. [akpm@linux-foundation.org: tweak comment text, per Mel] Signed-off-by: Minchan Kim <minchan@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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957f822a |
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08-Oct-2012 |
David Rientjes <rientjes@google.com> |
mm, numa: reclaim from all nodes within reclaim distance RECLAIM_DISTANCE represents the distance between nodes at which it is deemed too costly to allocate from; it's preferred to try to reclaim from a local zone before falling back to allocating on a remote node with such a distance. To do this, zone_reclaim_mode is set if the distance between any two nodes on the system is greather than this distance. This, however, ends up causing the page allocator to reclaim from every zone regardless of its affinity. What we really want is to reclaim only from zones that are closer than RECLAIM_DISTANCE. This patch adds a nodemask to each node that represents the set of nodes that are within this distance. During the zone iteration, if the bit for a zone's node is set for the local node, then reclaim is attempted; otherwise, the zone is skipped. [akpm@linux-foundation.org: fix CONFIG_NUMA=n build] Signed-off-by: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan@kernel.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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62997027 |
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08-Oct-2012 |
Mel Gorman <mgorman@suse.de> |
mm: compaction: clear PG_migrate_skip based on compaction and reclaim activity Compaction caches if a pageblock was scanned and no pages were isolated so that the pageblocks can be skipped in the future to reduce scanning. This information is not cleared by the page allocator based on activity due to the impact it would have to the page allocator fast paths. Hence there is a requirement that something clear the cache or pageblocks will be skipped forever. Currently the cache is cleared if there were a number of recent allocation failures and it has not been cleared within the last 5 seconds. Time-based decisions like this are terrible as they have no relationship to VM activity and is basically a big hammer. Unfortunately, accurate heuristics would add cost to some hot paths so this patch implements a rough heuristic. There are two cases where the cache is cleared. 1. If a !kswapd process completes a compaction cycle (migrate and free scanner meet), the zone is marked compact_blockskip_flush. When kswapd goes to sleep, it will clear the cache. This is expected to be the common case where the cache is cleared. It does not really matter if kswapd happens to be asleep or going to sleep when the flag is set as it will be woken on the next allocation request. 2. If there have been multiple failures recently and compaction just finished being deferred then a process will clear the cache and start a full scan. This situation happens if there are multiple high-order allocation requests under heavy memory pressure. The clearing of the PG_migrate_skip bits and other scans is inherently racy but the race is harmless. For allocations that can fail such as THP, they will simply fail. For requests that cannot fail, they will retry the allocation. Tests indicated that scanning rates were roughly similar to when the time-based heuristic was used and the allocation success rates were similar. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Richard Davies <richard@arachsys.com> Cc: Shaohua Li <shli@kernel.org> Cc: Avi Kivity <avi@redhat.com> Cc: Rafael Aquini <aquini@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c89511ab |
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08-Oct-2012 |
Mel Gorman <mgorman@suse.de> |
mm: compaction: Restart compaction from near where it left off This is almost entirely based on Rik's previous patches and discussions with him about how this might be implemented. Order > 0 compaction stops when enough free pages of the correct page order have been coalesced. When doing subsequent higher order allocations, it is possible for compaction to be invoked many times. However, the compaction code always starts out looking for things to compact at the start of the zone, and for free pages to compact things to at the end of the zone. This can cause quadratic behaviour, with isolate_freepages starting at the end of the zone each time, even though previous invocations of the compaction code already filled up all free memory on that end of the zone. This can cause isolate_freepages to take enormous amounts of CPU with certain workloads on larger memory systems. This patch caches where the migration and free scanner should start from on subsequent compaction invocations using the pageblock-skip information. When compaction starts it begins from the cached restart points and will update the cached restart points until a page is isolated or a pageblock is skipped that would have been scanned by synchronous compaction. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: Richard Davies <richard@arachsys.com> Cc: Shaohua Li <shli@kernel.org> Cc: Avi Kivity <avi@redhat.com> Acked-by: Rafael Aquini <aquini@redhat.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bb13ffeb |
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08-Oct-2012 |
Mel Gorman <mgorman@suse.de> |
mm: compaction: cache if a pageblock was scanned and no pages were isolated When compaction was implemented it was known that scanning could potentially be excessive. The ideal was that a counter be maintained for each pageblock but maintaining this information would incur a severe penalty due to a shared writable cache line. It has reached the point where the scanning costs are a serious problem, particularly on long-lived systems where a large process starts and allocates a large number of THPs at the same time. Instead of using a shared counter, this patch adds another bit to the pageblock flags called PG_migrate_skip. If a pageblock is scanned by either migrate or free scanner and 0 pages were isolated, the pageblock is marked to be skipped in the future. When scanning, this bit is checked before any scanning takes place and the block skipped if set. The main difficulty with a patch like this is "when to ignore the cached information?" If it's ignored too often, the scanning rates will still be excessive. If the information is too stale then allocations will fail that might have otherwise succeeded. In this patch o CMA always ignores the information o If the migrate and free scanner meet then the cached information will be discarded if it's at least 5 seconds since the last time the cache was discarded o If there are a large number of allocation failures, discard the cache. The time-based heuristic is very clumsy but there are few choices for a better event. Depending solely on multiple allocation failures still allows excessive scanning when THP allocations are failing in quick succession due to memory pressure. Waiting until memory pressure is relieved would cause compaction to continually fail instead of using reclaim/compaction to try allocate the page. The time-based mechanism is clumsy but a better option is not obvious. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: Richard Davies <richard@arachsys.com> Cc: Shaohua Li <shli@kernel.org> Cc: Avi Kivity <avi@redhat.com> Acked-by: Rafael Aquini <aquini@redhat.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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753341a4 |
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08-Oct-2012 |
Mel Gorman <mgorman@suse.de> |
revert "mm: have order > 0 compaction start off where it left" This reverts commit 7db8889ab05b ("mm: have order > 0 compaction start off where it left") and commit de74f1cc ("mm: have order > 0 compaction start near a pageblock with free pages"). These patches were a good idea and tests confirmed that they massively reduced the amount of scanning but the implementation is complex and tricky to understand. A later patch will cache what pageblocks should be skipped and reimplements the concept of compact_cached_free_pfn on top for both migration and free scanners. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: Richard Davies <richard@arachsys.com> Cc: Shaohua Li <shli@kernel.org> Cc: Avi Kivity <avi@redhat.com> Acked-by: Rafael Aquini <aquini@redhat.com> Acked-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d1ce749a |
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08-Oct-2012 |
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> |
cma: count free CMA pages Add NR_FREE_CMA_PAGES counter to be later used for checking watermark in __zone_watermark_ok(). For simplicity and to avoid #ifdef hell make this counter always available (not only when CONFIG_CMA=y). [akpm@linux-foundation.org: use conventional migratetype naming] Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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5515061d |
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31-Jul-2012 |
Mel Gorman <mgorman@suse.de> |
mm: throttle direct reclaimers if PF_MEMALLOC reserves are low and swap is backed by network storage If swap is backed by network storage such as NBD, there is a risk that a large number of reclaimers can hang the system by consuming all PF_MEMALLOC reserves. To avoid these hangs, the administrator must tune min_free_kbytes in advance which is a bit fragile. This patch throttles direct reclaimers if half the PF_MEMALLOC reserves are in use. If the system is routinely getting throttled the system administrator can increase min_free_kbytes so degradation is smoother but the system will keep running. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: David Miller <davem@davemloft.net> Cc: Neil Brown <neilb@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Eric B Munson <emunson@mgebm.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Cc: Mel Gorman <mgorman@suse.de> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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702d1a6e |
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31-Jul-2012 |
Minchan Kim <minchan@kernel.org> |
memory-hotplug: fix kswapd looping forever problem When hotplug offlining happens on zone A, it starts to mark freed page as MIGRATE_ISOLATE type in buddy for preventing further allocation. (MIGRATE_ISOLATE is very irony type because it's apparently on buddy but we can't allocate them). When the memory shortage happens during hotplug offlining, current task starts to reclaim, then wake up kswapd. Kswapd checks watermark, then go sleep because current zone_watermark_ok_safe doesn't consider MIGRATE_ISOLATE freed page count. Current task continue to reclaim in direct reclaim path without kswapd's helping. The problem is that zone->all_unreclaimable is set by only kswapd so that current task would be looping forever like below. __alloc_pages_slowpath restart: wake_all_kswapd rebalance: __alloc_pages_direct_reclaim do_try_to_free_pages if global_reclaim && !all_unreclaimable return 1; /* It means we did did_some_progress */ skip __alloc_pages_may_oom should_alloc_retry goto rebalance; If we apply KOSAKI's patch[1] which doesn't depends on kswapd about setting zone->all_unreclaimable, we can solve this problem by killing some task in direct reclaim path. But it doesn't wake up kswapd, still. It could be a problem still if other subsystem needs GFP_ATOMIC request. So kswapd should consider MIGRATE_ISOLATE when it calculate free pages BEFORE going sleep. This patch counts the number of MIGRATE_ISOLATE page block and zone_watermark_ok_safe will consider it if the system has such blocks (fortunately, it's very rare so no problem in POV overhead and kswapd is never hotpath). Copy/modify from Mel's quote " Ideal solution would be "allocating" the pageblock. It would keep the free space accounting as it is but historically, memory hotplug didn't allocate pages because it would be difficult to detect if a pageblock was isolated or if part of some balloon. Allocating just full pageblocks would work around this, However, it would play very badly with CMA. " [1] http://lkml.org/lkml/2012/6/14/74 [akpm@linux-foundation.org: simplify nr_zone_isolate_freepages(), rework zone_watermark_ok_safe() comment, simplify set_pageblock_isolate() and restore_pageblock_isolate()] [akpm@linux-foundation.org: fix CONFIG_MEMORY_ISOLATION=n build] Signed-off-by: Minchan Kim <minchan@kernel.org> Suggested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Tested-by: Aaditya Kumar <aaditya.kumar.30@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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9adb62a5 |
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31-Jul-2012 |
Jiang Liu <jiang.liu@huawei.com> |
mm/hotplug: correctly setup fallback zonelists when creating new pgdat When hotadd_new_pgdat() is called to create new pgdat for a new node, a fallback zonelist should be created for the new node. There's code to try to achieve that in hotadd_new_pgdat() as below: /* * The node we allocated has no zone fallback lists. For avoiding * to access not-initialized zonelist, build here. */ mutex_lock(&zonelists_mutex); build_all_zonelists(pgdat, NULL); mutex_unlock(&zonelists_mutex); But it doesn't work as expected. When hotadd_new_pgdat() is called, the new node is still in offline state because node_set_online(nid) hasn't been called yet. And build_all_zonelists() only builds zonelists for online nodes as: for_each_online_node(nid) { pg_data_t *pgdat = NODE_DATA(nid); build_zonelists(pgdat); build_zonelist_cache(pgdat); } Though we hope to create zonelist for the new pgdat, but it doesn't. So add a new parameter "pgdat" the build_all_zonelists() to build pgdat for the new pgdat too. Signed-off-by: Jiang Liu <liuj97@gmail.com> Signed-off-by: Xishi Qiu <qiuxishi@huawei.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Tony Luck <tony.luck@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Keping Chen <chenkeping@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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fe03025d |
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31-Jul-2012 |
Rabin Vincent <rabin@rab.in> |
mm: CONFIG_HAVE_MEMBLOCK_NODE -> CONFIG_HAVE_MEMBLOCK_NODE_MAP 0ee332c14518699 ("memblock: Kill early_node_map[]") wanted to replace CONFIG_ARCH_POPULATES_NODE_MAP with CONFIG_HAVE_MEMBLOCK_NODE_MAP but ended up replacing one occurence with a reference to the non-existent symbol CONFIG_HAVE_MEMBLOCK_NODE. The resulting omission of code would probably have been causing problems to 32-bit machines with memory hotplug. Signed-off-by: Rabin Vincent <rabin@rab.in> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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7db8889a |
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31-Jul-2012 |
Rik van Riel <riel@redhat.com> |
mm: have order > 0 compaction start off where it left Order > 0 compaction stops when enough free pages of the correct page order have been coalesced. When doing subsequent higher order allocations, it is possible for compaction to be invoked many times. However, the compaction code always starts out looking for things to compact at the start of the zone, and for free pages to compact things to at the end of the zone. This can cause quadratic behaviour, with isolate_freepages starting at the end of the zone each time, even though previous invocations of the compaction code already filled up all free memory on that end of the zone. This can cause isolate_freepages to take enormous amounts of CPU with certain workloads on larger memory systems. The obvious solution is to have isolate_freepages remember where it left off last time, and continue at that point the next time it gets invoked for an order > 0 compaction. This could cause compaction to fail if cc->free_pfn and cc->migrate_pfn are close together initially, in that case we restart from the end of the zone and try once more. Forced full (order == -1) compactions are left alone. [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: s/laste/last/, use 80 cols] Signed-off-by: Rik van Riel <riel@redhat.com> Reported-by: Jim Schutt <jaschut@sandia.gov> Tested-by: Jim Schutt <jaschut@sandia.gov> Cc: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ca28ddc9 |
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31-Jul-2012 |
Wanpeng Li <liwp@linux.vnet.ibm.com> |
mm: remove unused LRU_ALL_EVICTABLE Signed-off-by: Wanpeng Li <liwp.linux@gmail.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
c255a458 |
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31-Jul-2012 |
Andrew Morton <akpm@linux-foundation.org> |
memcg: rename config variables Sanity: CONFIG_CGROUP_MEM_RES_CTLR -> CONFIG_MEMCG CONFIG_CGROUP_MEM_RES_CTLR_SWAP -> CONFIG_MEMCG_SWAP CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED -> CONFIG_MEMCG_SWAP_ENABLED CONFIG_CGROUP_MEM_RES_CTLR_KMEM -> CONFIG_MEMCG_KMEM [mhocko@suse.cz: fix missed bits] Cc: Glauber Costa <glommer@parallels.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
d8adde17 |
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11-Jul-2012 |
Jiang Liu <jiang.liu@huawei.com> |
memory hotplug: fix invalid memory access caused by stale kswapd pointer kswapd_stop() is called to destroy the kswapd work thread when all memory of a NUMA node has been offlined. But kswapd_stop() only terminates the work thread without resetting NODE_DATA(nid)->kswapd to NULL. The stale pointer will prevent kswapd_run() from creating a new work thread when adding memory to the memory-less NUMA node again. Eventually the stale pointer may cause invalid memory access. An example stack dump as below. It's reproduced with 2.6.32, but latest kernel has the same issue. BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff81051a94>] exit_creds+0x12/0x78 PGD 0 Oops: 0000 [#1] SMP last sysfs file: /sys/devices/system/memory/memory391/state CPU 11 Modules linked in: cpufreq_conservative cpufreq_userspace cpufreq_powersave acpi_cpufreq microcode fuse loop dm_mod tpm_tis rtc_cmos i2c_i801 rtc_core tpm serio_raw pcspkr sg tpm_bios igb i2c_core iTCO_wdt rtc_lib mptctl iTCO_vendor_support button dca bnx2 usbhid hid uhci_hcd ehci_hcd usbcore sd_mod crc_t10dif edd ext3 mbcache jbd fan ide_pci_generic ide_core ata_generic ata_piix libata thermal processor thermal_sys hwmon mptsas mptscsih mptbase scsi_transport_sas scsi_mod Pid: 7949, comm: sh Not tainted 2.6.32.12-qiuxishi-5-default #92 Tecal RH2285 RIP: 0010:exit_creds+0x12/0x78 RSP: 0018:ffff8806044f1d78 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff880604f22140 RCX: 0000000000019502 RDX: 0000000000000000 RSI: 0000000000000202 RDI: 0000000000000000 RBP: ffff880604f22150 R08: 0000000000000000 R09: ffffffff81a4dc10 R10: 00000000000032a0 R11: ffff880006202500 R12: 0000000000000000 R13: 0000000000c40000 R14: 0000000000008000 R15: 0000000000000001 FS: 00007fbc03d066f0(0000) GS:ffff8800282e0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000000 CR3: 000000060f029000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process sh (pid: 7949, threadinfo ffff8806044f0000, task ffff880603d7c600) Stack: ffff880604f22140 ffffffff8103aac5 ffff880604f22140 ffffffff8104d21e ffff880006202500 0000000000008000 0000000000c38000 ffffffff810bd5b1 0000000000000000 ffff880603d7c600 00000000ffffdd29 0000000000000003 Call Trace: __put_task_struct+0x5d/0x97 kthread_stop+0x50/0x58 offline_pages+0x324/0x3da memory_block_change_state+0x179/0x1db store_mem_state+0x9e/0xbb sysfs_write_file+0xd0/0x107 vfs_write+0xad/0x169 sys_write+0x45/0x6e system_call_fastpath+0x16/0x1b Code: ff 4d 00 0f 94 c0 84 c0 74 08 48 89 ef e8 1f fd ff ff 5b 5d 31 c0 41 5c c3 53 48 8b 87 20 06 00 00 48 89 fb 48 8b bf 18 06 00 00 <8b> 00 48 c7 83 18 06 00 00 00 00 00 00 f0 ff 0f 0f 94 c0 84 c0 RIP exit_creds+0x12/0x78 RSP <ffff8806044f1d78> CR2: 0000000000000000 [akpm@linux-foundation.org: add pglist_data.kswapd locking comments] Signed-off-by: Xishi Qiu <qiuxishi@huawei.com> Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
46028e6d |
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15-Jun-2012 |
Wanpeng Li <liwp@linux.vnet.ibm.com> |
mm: cleanup on the comments of zone_reclaim_stat Signed-off-by: Wanpeng Li <liwp.linux@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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#
7f5e86c2 |
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29-May-2012 |
Konstantin Khlebnikov <khlebnikov@openvz.org> |
mm: add link from struct lruvec to struct zone This is the first stage of struct mem_cgroup_zone removal. Further patches replace struct mem_cgroup_zone with a pointer to struct lruvec. If CONFIG_CGROUP_MEM_RES_CTLR=n lruvec_zone() is just container_of(). Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
89abfab1 |
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29-May-2012 |
Hugh Dickins <hughd@google.com> |
mm/memcg: move reclaim_stat into lruvec With mem_cgroup_disabled() now explicit, it becomes clear that the zone_reclaim_stat structure actually belongs in lruvec, per-zone when memcg is disabled but per-memcg per-zone when it's enabled. We can delete mem_cgroup_get_reclaim_stat(), and change update_page_reclaim_stat() to update just the one set of stats, the one which get_scan_count() will actually use. Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@parallels.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
f3fd4a61 |
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29-May-2012 |
Konstantin Khlebnikov <khlebnikov@openvz.org> |
mm: remove lru type checks from __isolate_lru_page() After patch "mm: forbid lumpy-reclaim in shrink_active_list()" we can completely remove anon/file and active/inactive lru type filters from __isolate_lru_page(), because isolation for 0-order reclaim always isolates pages from right lru list. And pages-isolation for lumpy shrink_inactive_list() or memory-compaction anyway allowed to isolate pages from all evictable lru lists. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@parallels.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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49f223a9 |
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24-Jan-2012 |
Marek Szyprowski <m.szyprowski@samsung.com> |
mm: trigger page reclaim in alloc_contig_range() to stabilise watermarks alloc_contig_range() performs memory allocation so it also should keep track on keeping the correct level of memory watermarks. This commit adds a call to *_slowpath style reclaim to grab enough pages to make sure that the final collection of contiguous pages from freelists will not starve the system. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> CC: Michal Nazarewicz <mina86@mina86.com> Tested-by: Rob Clark <rob.clark@linaro.org> Tested-by: Ohad Ben-Cohen <ohad@wizery.com> Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Tested-by: Robert Nelson <robertcnelson@gmail.com> Tested-by: Barry Song <Baohua.Song@csr.com>
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#
47118af0 |
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29-Dec-2011 |
Michal Nazarewicz <mina86@mina86.com> |
mm: mmzone: MIGRATE_CMA migration type added The MIGRATE_CMA migration type has two main characteristics: (i) only movable pages can be allocated from MIGRATE_CMA pageblocks and (ii) page allocator will never change migration type of MIGRATE_CMA pageblocks. This guarantees (to some degree) that page in a MIGRATE_CMA page block can always be migrated somewhere else (unless there's no memory left in the system). It is designed to be used for allocating big chunks (eg. 10MiB) of physically contiguous memory. Once driver requests contiguous memory, pages from MIGRATE_CMA pageblocks may be migrated away to create a contiguous block. To minimise number of migrations, MIGRATE_CMA migration type is the last type tried when page allocator falls back to other migration types when requested. Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: Rob Clark <rob.clark@linaro.org> Tested-by: Ohad Ben-Cohen <ohad@wizery.com> Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Tested-by: Robert Nelson <robertcnelson@gmail.com> Tested-by: Barry Song <Baohua.Song@csr.com>
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#
35fca53e |
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15-Apr-2012 |
Wang YanQing <udknight@gmail.com> |
mmzone: fix comment typo coelesce -> coalesce Signed-off-by: Wang YanQing <udknight@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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#
aff62249 |
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21-Mar-2012 |
Rik van Riel <riel@redhat.com> |
vmscan: only defer compaction for failed order and higher Currently a failed order-9 (transparent hugepage) compaction can lead to memory compaction being temporarily disabled for a memory zone. Even if we only need compaction for an order 2 allocation, eg. for jumbo frames networking. The fix is relatively straightforward: keep track of the highest order at which compaction is succeeding, and only defer compaction for orders at which compaction is failing. Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hillf Danton <dhillf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
4111304d |
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12-Jan-2012 |
Hugh Dickins <hughd@google.com> |
mm: enum lru_list lru Mostly we use "enum lru_list lru": change those few "l"s to "lru"s. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
c8244935 |
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12-Jan-2012 |
Mel Gorman <mgorman@suse.de> |
mm: compaction: make isolate_lru_page() filter-aware again Commit 39deaf85 ("mm: compaction: make isolate_lru_page() filter-aware") noted that compaction does not migrate dirty or writeback pages and that is was meaningless to pick the page and re-add it to the LRU list. This had to be partially reverted because some dirty pages can be migrated by compaction without blocking. This patch updates "mm: compaction: make isolate_lru_page" by skipping over pages that migration has no possibility of migrating to minimise LRU disruption. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel<riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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6290df54 |
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12-Jan-2012 |
Johannes Weiner <jweiner@redhat.com> |
mm: collect LRU list heads into struct lruvec Having a unified structure with a LRU list set for both global zones and per-memcg zones allows to keep that code simple which deals with LRU lists and does not care about the container itself. Once the per-memcg LRU lists directly link struct pages, the isolation function and all other list manipulations are shared between the memcg case and the global LRU case. Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Ying Han <yinghan@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
ab8fabd4 |
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10-Jan-2012 |
Johannes Weiner <jweiner@redhat.com> |
mm: exclude reserved pages from dirtyable memory Per-zone dirty limits try to distribute page cache pages allocated for writing across zones in proportion to the individual zone sizes, to reduce the likelihood of reclaim having to write back individual pages from the LRU lists in order to make progress. This patch: The amount of dirtyable pages should not include the full number of free pages: there is a number of reserved pages that the page allocator and kswapd always try to keep free. The closer (reclaimable pages - dirty pages) is to the number of reserved pages, the more likely it becomes for reclaim to run into dirty pages: +----------+ --- | anon | | +----------+ | | | | | | -- dirty limit new -- flusher new | file | | | | | | | | | -- dirty limit old -- flusher old | | | +----------+ --- reclaim | reserved | +----------+ | kernel | +----------+ This patch introduces a per-zone dirty reserve that takes both the lowmem reserve as well as the high watermark of the zone into account, and a global sum of those per-zone values that is subtracted from the global amount of dirtyable pages. The lowmem reserve is unavailable to page cache allocations and kswapd tries to keep the high watermark free. We don't want to end up in a situation where reclaim has to clean pages in order to balance zones. Not treating reserved pages as dirtyable on a global level is only a conceptual fix. In reality, dirty pages are not distributed equally across zones and reclaim runs into dirty pages on a regular basis. But it is important to get this right before tackling the problem on a per-zone level, where the distance between reclaim and the dirty pages is mostly much smaller in absolute numbers. [akpm@linux-foundation.org: fix highmem build] Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Chris Mason <chris.mason@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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0ee332c1 |
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08-Dec-2011 |
Tejun Heo <tj@kernel.org> |
memblock: Kill early_node_map[] Now all ARCH_POPULATES_NODE_MAP archs select HAVE_MEBLOCK_NODE_MAP - there's no user of early_node_map[] left. Kill early_node_map[] and replace ARCH_POPULATES_NODE_MAP with HAVE_MEMBLOCK_NODE_MAP. Also, relocate for_each_mem_pfn_range() and helper from mm.h to memblock.h as page_alloc.c would no longer host an alternative implementation. This change is ultimately one to one mapping and shouldn't cause any observable difference; however, after the recent changes, there are some functions which now would fit memblock.c better than page_alloc.c and dependency on HAVE_MEMBLOCK_NODE_MAP instead of HAVE_MEMBLOCK doesn't make much sense on some of them. Further cleanups for functions inside HAVE_MEMBLOCK_NODE_MAP in mm.h would be nice. -v2: Fix compile bug introduced by mis-spelling CONFIG_HAVE_MEMBLOCK_NODE_MAP to CONFIG_MEMBLOCK_HAVE_NODE_MAP in mmzone.h. Reported by Stephen Rothwell. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Chen Liqin <liqin.chen@sunplusct.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: "H. Peter Anvin" <hpa@zytor.com>
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49ea7eb6 |
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31-Oct-2011 |
Mel Gorman <mgorman@suse.de> |
mm: vmscan: immediately reclaim end-of-LRU dirty pages when writeback completes When direct reclaim encounters a dirty page, it gets recycled around the LRU for another cycle. This patch marks the page PageReclaim similar to deactivate_page() so that the page gets reclaimed almost immediately after the page gets cleaned. This is to avoid reclaiming clean pages that are younger than a dirty page encountered at the end of the LRU that might have been something like a use-once page. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <jweiner@redhat.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Alex Elder <aelder@sgi.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Chris Mason <chris.mason@oracle.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
ee72886d |
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31-Oct-2011 |
Mel Gorman <mel@csn.ul.ie> |
mm: vmscan: do not writeback filesystem pages in direct reclaim Testing from the XFS folk revealed that there is still too much I/O from the end of the LRU in kswapd. Previously it was considered acceptable by VM people for a small number of pages to be written back from reclaim with testing generally showing about 0.3% of pages reclaimed were written back (higher if memory was low). That writing back a small number of pages is ok has been heavily disputed for quite some time and Dave Chinner explained it well; It doesn't have to be a very high number to be a problem. IO is orders of magnitude slower than the CPU time it takes to flush a page, so the cost of making a bad flush decision is very high. And single page writeback from the LRU is almost always a bad flush decision. To complicate matters, filesystems respond very differently to requests from reclaim according to Christoph Hellwig; xfs tries to write it back if the requester is kswapd ext4 ignores the request if it's a delayed allocation btrfs ignores the request As a result, each filesystem has different performance characteristics when under memory pressure and there are many pages being dirtied. In some cases, the request is ignored entirely so the VM cannot depend on the IO being dispatched. The objective of this series is to reduce writing of filesystem-backed pages from reclaim, play nicely with writeback that is already in progress and throttle reclaim appropriately when writeback pages are encountered. The assumption is that the flushers will always write pages faster than if reclaim issues the IO. A secondary goal is to avoid the problem whereby direct reclaim splices two potentially deep call stacks together. There is a potential new problem as reclaim has less control over how long before a page in a particularly zone or container is cleaned and direct reclaimers depend on kswapd or flusher threads to do the necessary work. However, as filesystems sometimes ignore direct reclaim requests already, it is not expected to be a serious issue. Patch 1 disables writeback of filesystem pages from direct reclaim entirely. Anonymous pages are still written. Patch 2 removes dead code in lumpy reclaim as it is no longer able to synchronously write pages. This hurts lumpy reclaim but there is an expectation that compaction is used for hugepage allocations these days and lumpy reclaim's days are numbered. Patches 3-4 add warnings to XFS and ext4 if called from direct reclaim. With patch 1, this "never happens" and is intended to catch regressions in this logic in the future. Patch 5 disables writeback of filesystem pages from kswapd unless the priority is raised to the point where kswapd is considered to be in trouble. Patch 6 throttles reclaimers if too many dirty pages are being encountered and the zones or backing devices are congested. Patch 7 invalidates dirty pages found at the end of the LRU so they are reclaimed quickly after being written back rather than waiting for a reclaimer to find them I consider this series to be orthogonal to the writeback work but it is worth noting that the writeback work affects the viability of patch 8 in particular. I tested this on ext4 and xfs using fs_mark, a simple writeback test based on dd and a micro benchmark that does a streaming write to a large mapping (exercises use-once LRU logic) followed by streaming writes to a mix of anonymous and file-backed mappings. The command line for fs_mark when botted with 512M looked something like ./fs_mark -d /tmp/fsmark-2676 -D 100 -N 150 -n 150 -L 25 -t 1 -S0 -s 10485760 The number of files was adjusted depending on the amount of available memory so that the files created was about 3xRAM. For multiple threads, the -d switch is specified multiple times. The test machine is x86-64 with an older generation of AMD processor with 4 cores. The underlying storage was 4 disks configured as RAID-0 as this was the best configuration of storage I had available. Swap is on a separate disk. Dirty ratio was tuned to 40% instead of the default of 20%. Testing was run with and without monitors to both verify that the patches were operating as expected and that any performance gain was real and not due to interference from monitors. Here is a summary of results based on testing XFS. 512M1P-xfs Files/s mean 32.69 ( 0.00%) 34.44 ( 5.08%) 512M1P-xfs Elapsed Time fsmark 51.41 48.29 512M1P-xfs Elapsed Time simple-wb 114.09 108.61 512M1P-xfs Elapsed Time mmap-strm 113.46 109.34 512M1P-xfs Kswapd efficiency fsmark 62% 63% 512M1P-xfs Kswapd efficiency simple-wb 56% 61% 512M1P-xfs Kswapd efficiency mmap-strm 44% 42% 512M-xfs Files/s mean 30.78 ( 0.00%) 35.94 (14.36%) 512M-xfs Elapsed Time fsmark 56.08 48.90 512M-xfs Elapsed Time simple-wb 112.22 98.13 512M-xfs Elapsed Time mmap-strm 219.15 196.67 512M-xfs Kswapd efficiency fsmark 54% 56% 512M-xfs Kswapd efficiency simple-wb 54% 55% 512M-xfs Kswapd efficiency mmap-strm 45% 44% 512M-4X-xfs Files/s mean 30.31 ( 0.00%) 33.33 ( 9.06%) 512M-4X-xfs Elapsed Time fsmark 63.26 55.88 512M-4X-xfs Elapsed Time simple-wb 100.90 90.25 512M-4X-xfs Elapsed Time mmap-strm 261.73 255.38 512M-4X-xfs Kswapd efficiency fsmark 49% 50% 512M-4X-xfs Kswapd efficiency simple-wb 54% 56% 512M-4X-xfs Kswapd efficiency mmap-strm 37% 36% 512M-16X-xfs Files/s mean 60.89 ( 0.00%) 65.22 ( 6.64%) 512M-16X-xfs Elapsed Time fsmark 67.47 58.25 512M-16X-xfs Elapsed Time simple-wb 103.22 90.89 512M-16X-xfs Elapsed Time mmap-strm 237.09 198.82 512M-16X-xfs Kswapd efficiency fsmark 45% 46% 512M-16X-xfs Kswapd efficiency simple-wb 53% 55% 512M-16X-xfs Kswapd efficiency mmap-strm 33% 33% Up until 512-4X, the FSmark improvements were statistically significant. For the 4X and 16X tests the results were within standard deviations but just barely. The time to completion for all tests is improved which is an important result. In general, kswapd efficiency is not affected by skipping dirty pages. 1024M1P-xfs Files/s mean 39.09 ( 0.00%) 41.15 ( 5.01%) 1024M1P-xfs Elapsed Time fsmark 84.14 80.41 1024M1P-xfs Elapsed Time simple-wb 210.77 184.78 1024M1P-xfs Elapsed Time mmap-strm 162.00 160.34 1024M1P-xfs Kswapd efficiency fsmark 69% 75% 1024M1P-xfs Kswapd efficiency simple-wb 71% 77% 1024M1P-xfs Kswapd efficiency mmap-strm 43% 44% 1024M-xfs Files/s mean 35.45 ( 0.00%) 37.00 ( 4.19%) 1024M-xfs Elapsed Time fsmark 94.59 91.00 1024M-xfs Elapsed Time simple-wb 229.84 195.08 1024M-xfs Elapsed Time mmap-strm 405.38 440.29 1024M-xfs Kswapd efficiency fsmark 79% 71% 1024M-xfs Kswapd efficiency simple-wb 74% 74% 1024M-xfs Kswapd efficiency mmap-strm 39% 42% 1024M-4X-xfs Files/s mean 32.63 ( 0.00%) 35.05 ( 6.90%) 1024M-4X-xfs Elapsed Time fsmark 103.33 97.74 1024M-4X-xfs Elapsed Time simple-wb 204.48 178.57 1024M-4X-xfs Elapsed Time mmap-strm 528.38 511.88 1024M-4X-xfs Kswapd efficiency fsmark 81% 70% 1024M-4X-xfs Kswapd efficiency simple-wb 73% 72% 1024M-4X-xfs Kswapd efficiency mmap-strm 39% 38% 1024M-16X-xfs Files/s mean 42.65 ( 0.00%) 42.97 ( 0.74%) 1024M-16X-xfs Elapsed Time fsmark 103.11 99.11 1024M-16X-xfs Elapsed Time simple-wb 200.83 178.24 1024M-16X-xfs Elapsed Time mmap-strm 397.35 459.82 1024M-16X-xfs Kswapd efficiency fsmark 84% 69% 1024M-16X-xfs Kswapd efficiency simple-wb 74% 73% 1024M-16X-xfs Kswapd efficiency mmap-strm 39% 40% All FSMark tests up to 16X had statistically significant improvements. For the most part, tests are completing faster with the exception of the streaming writes to a mixture of anonymous and file-backed mappings which were slower in two cases In the cases where the mmap-strm tests were slower, there was more swapping due to dirty pages being skipped. The number of additional pages swapped is almost identical to the fewer number of pages written from reclaim. In other words, roughly the same number of pages were reclaimed but swapping was slower. As the test is a bit unrealistic and stresses memory heavily, the small shift is acceptable. 4608M1P-xfs Files/s mean 29.75 ( 0.00%) 30.96 ( 3.91%) 4608M1P-xfs Elapsed Time fsmark 512.01 492.15 4608M1P-xfs Elapsed Time simple-wb 618.18 566.24 4608M1P-xfs Elapsed Time mmap-strm 488.05 465.07 4608M1P-xfs Kswapd efficiency fsmark 93% 86% 4608M1P-xfs Kswapd efficiency simple-wb 88% 84% 4608M1P-xfs Kswapd efficiency mmap-strm 46% 45% 4608M-xfs Files/s mean 27.60 ( 0.00%) 28.85 ( 4.33%) 4608M-xfs Elapsed Time fsmark 555.96 532.34 4608M-xfs Elapsed Time simple-wb 659.72 571.85 4608M-xfs Elapsed Time mmap-strm 1082.57 1146.38 4608M-xfs Kswapd efficiency fsmark 89% 91% 4608M-xfs Kswapd efficiency simple-wb 88% 82% 4608M-xfs Kswapd efficiency mmap-strm 48% 46% 4608M-4X-xfs Files/s mean 26.00 ( 0.00%) 27.47 ( 5.35%) 4608M-4X-xfs Elapsed Time fsmark 592.91 564.00 4608M-4X-xfs Elapsed Time simple-wb 616.65 575.07 4608M-4X-xfs Elapsed Time mmap-strm 1773.02 1631.53 4608M-4X-xfs Kswapd efficiency fsmark 90% 94% 4608M-4X-xfs Kswapd efficiency simple-wb 87% 82% 4608M-4X-xfs Kswapd efficiency mmap-strm 43% 43% 4608M-16X-xfs Files/s mean 26.07 ( 0.00%) 26.42 ( 1.32%) 4608M-16X-xfs Elapsed Time fsmark 602.69 585.78 4608M-16X-xfs Elapsed Time simple-wb 606.60 573.81 4608M-16X-xfs Elapsed Time mmap-strm 1549.75 1441.86 4608M-16X-xfs Kswapd efficiency fsmark 98% 98% 4608M-16X-xfs Kswapd efficiency simple-wb 88% 82% 4608M-16X-xfs Kswapd efficiency mmap-strm 44% 42% Unlike the other tests, the fsmark results are not statistically significant but the min and max times are both improved and for the most part, tests completed faster. There are other indications that this is an improvement as well. For example, in the vast majority of cases, there were fewer pages scanned by direct reclaim implying in many cases that stalls due to direct reclaim are reduced. KSwapd is scanning more due to skipping dirty pages which is unfortunate but the CPU usage is still acceptable In an earlier set of tests, I used blktrace and in almost all cases throughput throughout the entire test was higher. However, I ended up discarding those results as recording blktrace data was too heavy for my liking. On a laptop, I plugged in a USB stick and ran a similar tests of tests using it as backing storage. A desktop environment was running and for the entire duration of the tests, firefox and gnome terminal were launching and exiting to vaguely simulate a user. 1024M-xfs Files/s mean 0.41 ( 0.00%) 0.44 ( 6.82%) 1024M-xfs Elapsed Time fsmark 2053.52 1641.03 1024M-xfs Elapsed Time simple-wb 1229.53 768.05 1024M-xfs Elapsed Time mmap-strm 4126.44 4597.03 1024M-xfs Kswapd efficiency fsmark 84% 85% 1024M-xfs Kswapd efficiency simple-wb 92% 81% 1024M-xfs Kswapd efficiency mmap-strm 60% 51% 1024M-xfs Avg wait ms fsmark 5404.53 4473.87 1024M-xfs Avg wait ms simple-wb 2541.35 1453.54 1024M-xfs Avg wait ms mmap-strm 3400.25 3852.53 The mmap-strm results were hurt because firefox launching had a tendency to push the test out of memory. On the postive side, firefox launched marginally faster with the patches applied. Time to completion for many tests was faster but more importantly - the "Avg wait" time as measured by iostat was far lower implying the system would be more responsive. It was also the case that "Avg wait ms" on the root filesystem was lower. I tested it manually and while the system felt slightly more responsive while copying data to a USB stick, it was marginal enough that it could be my imagination. This patch: do not writeback filesystem pages in direct reclaim. When kswapd is failing to keep zones above the min watermark, a process will enter direct reclaim in the same manner kswapd does. If a dirty page is encountered during the scan, this page is written to backing storage using mapping->writepage. This causes two problems. First, it can result in very deep call stacks, particularly if the target storage or filesystem are complex. Some filesystems ignore write requests from direct reclaim as a result. The second is that a single-page flush is inefficient in terms of IO. While there is an expectation that the elevator will merge requests, this does not always happen. Quoting Christoph Hellwig; The elevator has a relatively small window it can operate on, and can never fix up a bad large scale writeback pattern. This patch prevents direct reclaim writing back filesystem pages by checking if current is kswapd. Anonymous pages are still written to swap as there is not the equivalent of a flusher thread for anonymous pages. If the dirty pages cannot be written back, they are placed back on the LRU lists. There is now a direct dependency on dirty page balancing to prevent too many pages in the system being dirtied which would prevent reclaim making forward progress. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Alex Elder <aelder@sgi.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Chris Mason <chris.mason@oracle.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f80c0673 |
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31-Oct-2011 |
Minchan Kim <minchan.kim@gmail.com> |
mm: zone_reclaim: make isolate_lru_page() filter-aware In __zone_reclaim case, we don't want to shrink mapped page. Nonetheless, we have isolated mapped page and re-add it into LRU's head. It's unnecessary CPU overhead and makes LRU churning. Of course, when we isolate the page, the page might be mapped but when we try to migrate the page, the page would be not mapped. So it could be migrated. But race is rare and although it happens, it's no big deal. Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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39deaf85 |
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31-Oct-2011 |
Minchan Kim <minchan.kim@gmail.com> |
mm: compaction: make isolate_lru_page() filter-aware In async mode, compaction doesn't migrate dirty or writeback pages. So, it's meaningless to pick the page and re-add it to lru list. Of course, when we isolate the page in compaction, the page might be dirty or writeback but when we try to migrate the page, the page would be not dirty, writeback. So it could be migrated. But it's very unlikely as isolate and migration cycle is much faster than writeout. So, this patch helps cpu overhead and prevent unnecessary LRU churning. Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4356f21d |
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31-Oct-2011 |
Minchan Kim <minchan.kim@gmail.com> |
mm: change isolate mode from #define to bitwise type Change ISOLATE_XXX macro with bitwise isolate_mode_t type. Normally, macro isn't recommended as it's type-unsafe and making debugging harder as symbol cannot be passed throught to the debugger. Quote from Johannes " Hmm, it would probably be cleaner to fully convert the isolation mode into independent flags. INACTIVE, ACTIVE, BOTH is currently a tri-state among flags, which is a bit ugly." This patch moves isolate mode from swap.h to mmzone.h by memcontrol.h Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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60063497 |
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26-Jul-2011 |
Arun Sharma <asharma@fb.com> |
atomic: use <linux/atomic.h> This allows us to move duplicated code in <asm/atomic.h> (atomic_inc_not_zero() for now) to <linux/atomic.h> Signed-off-by: Arun Sharma <asharma@fb.com> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bb2a0de9 |
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26-Jul-2011 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
memcg: consolidate memory cgroup lru stat functions In mm/memcontrol.c, there are many lru stat functions as.. mem_cgroup_zone_nr_lru_pages mem_cgroup_node_nr_file_lru_pages mem_cgroup_nr_file_lru_pages mem_cgroup_node_nr_anon_lru_pages mem_cgroup_nr_anon_lru_pages mem_cgroup_node_nr_unevictable_lru_pages mem_cgroup_nr_unevictable_lru_pages mem_cgroup_node_nr_lru_pages mem_cgroup_nr_lru_pages mem_cgroup_get_local_zonestat Some of them are under #ifdef MAX_NUMNODES >1 and others are not. This seems bad. This patch consolidates all functions into mem_cgroup_zone_nr_lru_pages() mem_cgroup_node_nr_lru_pages() mem_cgroup_nr_lru_pages() For these functions, "which LRU?" information is passed by a mask. example: mem_cgroup_nr_lru_pages(mem, BIT(LRU_ACTIVE_ANON)) And I added some macro as ALL_LRU, ALL_LRU_FILE, ALL_LRU_ANON. example: mem_cgroup_nr_lru_pages(mem, ALL_LRU) BTW, considering layout of NUMA memory placement of counters, this patch seems to be better. Now, when we gather all LRU information, we scan in following orer for_each_lru -> for_each_node -> for_each_zone. This means we'll touch cache lines in different node in turn. After patch, we'll scan for_each_node -> for_each_zone -> for_each_lru(mask) Then, we'll gather information in the same cacheline at once. [akpm@linux-foundation.org: fix warnigns, build error] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c6830c22 |
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16-Jun-2011 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
Fix node_start/end_pfn() definition for mm/page_cgroup.c commit 21a3c96 uses node_start/end_pfn(nid) for detection start/end of nodes. But, it's not defined in linux/mmzone.h but defined in /arch/???/include/mmzone.h which is included only under CONFIG_NEED_MULTIPLE_NODES=y. Then, we see mm/page_cgroup.c: In function 'page_cgroup_init': mm/page_cgroup.c:308: error: implicit declaration of function 'node_start_pfn' mm/page_cgroup.c:309: error: implicit declaration of function 'node_end_pfn' So, fixiing page_cgroup.c is an idea... But node_start_pfn()/node_end_pfn() is a very generic macro and should be implemented in the same manner for all archs. (m32r has different implementation...) This patch removes definitions of node_start/end_pfn() in each archs and defines a unified one in linux/mmzone.h. It's not under CONFIG_NEED_MULTIPLE_NODES, now. A result of macro expansion is here (mm/page_cgroup.c) for !NUMA start_pfn = ((&contig_page_data)->node_start_pfn); end_pfn = ({ pg_data_t *__pgdat = (&contig_page_data); __pgdat->node_start_pfn + __pgdat->node_spanned_pages;}); for NUMA (x86-64) start_pfn = ((node_data[nid])->node_start_pfn); end_pfn = ({ pg_data_t *__pgdat = (node_data[nid]); __pgdat->node_start_pfn + __pgdat->node_spanned_pages;}); Changelog: - fixed to avoid using "nid" twice in node_end_pfn() macro. Reported-and-acked-by: Randy Dunlap <randy.dunlap@oracle.com> Reported-and-tested-by: Ingo Molnar <mingo@elte.hu> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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246e87a9 |
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26-May-2011 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
memcg: fix get_scan_count() for small targets During memory reclaim we determine the number of pages to be scanned per zone as (anon + file) >> priority. Assume scan = (anon + file) >> priority. If scan < SWAP_CLUSTER_MAX, the scan will be skipped for this time and priority gets higher. This has some problems. 1. This increases priority as 1 without any scan. To do scan in this priority, amount of pages should be larger than 512M. If pages>>priority < SWAP_CLUSTER_MAX, it's recorded and scan will be batched, later. (But we lose 1 priority.) If memory size is below 16M, pages >> priority is 0 and no scan in DEF_PRIORITY forever. 2. If zone->all_unreclaimabe==true, it's scanned only when priority==0. So, x86's ZONE_DMA will never be recoverred until the user of pages frees memory by itself. 3. With memcg, the limit of memory can be small. When using small memcg, it gets priority < DEF_PRIORITY-2 very easily and need to call wait_iff_congested(). For doing scan before priorty=9, 64MB of memory should be used. Then, this patch tries to scan SWAP_CLUSTER_MAX of pages in force...when 1. the target is enough small. 2. it's kswapd or memcg reclaim. Then we can avoid rapid priority drop and may be able to recover all_unreclaimable in a small zones. And this patch removes nr_saved_scan. This will allow scanning in this priority even when pages >> priority is very small. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Ying Han <yinghan@google.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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7b7bf499 |
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19-May-2011 |
Will Deacon <will@kernel.org> |
ARM: 6913/1: sparsemem: allow pfn_valid to be overridden when using SPARSEMEM In commit eb33575c ("[ARM] Double check memmap is actually valid with a memmap has unexpected holes V2"), a new function, memmap_valid_within, was introduced to mmzone.h so that holes in the memmap which pass pfn_valid in SPARSEMEM configurations can be detected and avoided. The fix to this problem checks that the pfn <-> page linkages are correct by calculating the page for the pfn and then checking that page_to_pfn on that page returns the original pfn. Unfortunately, in SPARSEMEM configurations, this results in reading from the page flags to determine the correct section. Since the memmap here has been freed, junk is read from memory and the check is no longer robust. In the best case, reading from /proc/pagetypeinfo will give you the wrong answer. In the worst case, you get SEGVs, Kernel OOPses and hung CPUs. Furthermore, ioremap implementations that use pfn_valid to disallow the remapping of normal memory will break. This patch allows architectures to provide their own pfn_valid function instead of using the default implementation used by sparsemem. The architecture-specific version is aware of the memmap state and will return false when passed a pfn for a freed page within a valid section. Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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a539f353 |
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24-May-2011 |
Daniel Kiper <dkiper@net-space.pl> |
mm: add SECTION_ALIGN_UP() and SECTION_ALIGN_DOWN() macro Add SECTION_ALIGN_UP() and SECTION_ALIGN_DOWN() macro which aligns given pfn to upper section and lower section boundary accordingly. Required for the latest memory hotplug support for the Xen balloon driver. Signed-off-by: Daniel Kiper <dkiper@net-space.pl> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e3c40f37 |
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24-May-2011 |
Daniel Kiper <dkiper@net-space.pl> |
mm: pfn_to_section_nr()/section_nr_to_pfn() is valid only in CONFIG_SPARSEMEM context pfn_to_section_nr()/section_nr_to_pfn() is valid only in CONFIG_SPARSEMEM context. Move it to proper place. Signed-off-by: Daniel Kiper <dkiper@net-space.pl> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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25a64ec1 |
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03-Feb-2011 |
Pete Zaitcev <zaitcev@kotori.zaitcev.us> |
fix comment spelling becausse => because Signed-off-by: Pete Zaitcev <zaitcev@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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79134171 |
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13-Jan-2011 |
Andrea Arcangeli <aarcange@redhat.com> |
thp: transparent hugepage vmstat Add hugepage stat information to /proc/vmstat and /proc/meminfo. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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99504748 |
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13-Jan-2011 |
Mel Gorman <mel@csn.ul.ie> |
mm: kswapd: stop high-order balancing when any suitable zone is balanced Simon Kirby reported the following problem We're seeing cases on a number of servers where cache never fully grows to use all available memory. Sometimes we see servers with 4 GB of memory that never seem to have less than 1.5 GB free, even with a constantly-active VM. In some cases, these servers also swap out while this happens, even though they are constantly reading the working set into memory. We have been seeing this happening for a long time; I don't think it's anything recent, and it still happens on 2.6.36. After some debugging work by Simon, Dave Hansen and others, the prevaling theory became that kswapd is reclaiming order-3 pages requested by SLUB too aggressive about it. There are two apparent problems here. On the target machine, there is a small Normal zone in comparison to DMA32. As kswapd tries to balance all zones, it would continually try reclaiming for Normal even though DMA32 was balanced enough for callers. The second problem is that sleeping_prematurely() does not use the same logic as balance_pgdat() when deciding whether to sleep or not. This keeps kswapd artifically awake. A number of tests were run and the figures from previous postings will look very different for a few reasons. One, the old figures were forcing my network card to use GFP_ATOMIC in attempt to replicate Simon's problem. Second, I previous specified slub_min_order=3 again in an attempt to reproduce Simon's problem. In this posting, I'm depending on Simon to say whether his problem is fixed or not and these figures are to show the impact to the ordinary cases. Finally, the "vmscan" figures are taken from /proc/vmstat instead of the tracepoints. There is less information but recording is less disruptive. The first test of relevance was postmark with a process running in the background reading a large amount of anonymous memory in blocks. The objective was to vaguely simulate what was happening on Simon's machine and it's memory intensive enough to have kswapd awake. POSTMARK traceonly kanyzone Transactions per second: 156.00 ( 0.00%) 153.00 (-1.96%) Data megabytes read per second: 21.51 ( 0.00%) 21.52 ( 0.05%) Data megabytes written per second: 29.28 ( 0.00%) 29.11 (-0.58%) Files created alone per second: 250.00 ( 0.00%) 416.00 (39.90%) Files create/transact per second: 79.00 ( 0.00%) 76.00 (-3.95%) Files deleted alone per second: 520.00 ( 0.00%) 420.00 (-23.81%) Files delete/transact per second: 79.00 ( 0.00%) 76.00 (-3.95%) MMTests Statistics: duration User/Sys Time Running Test (seconds) 16.58 17.4 Total Elapsed Time (seconds) 218.48 222.47 VMstat Reclaim Statistics: vmscan Direct reclaims 0 4 Direct reclaim pages scanned 0 203 Direct reclaim pages reclaimed 0 184 Kswapd pages scanned 326631 322018 Kswapd pages reclaimed 312632 309784 Kswapd low wmark quickly 1 4 Kswapd high wmark quickly 122 475 Kswapd skip congestion_wait 1 0 Pages activated 700040 705317 Pages deactivated 212113 203922 Pages written 9875 6363 Total pages scanned 326631 322221 Total pages reclaimed 312632 309968 %age total pages scanned/reclaimed 95.71% 96.20% %age total pages scanned/written 3.02% 1.97% proc vmstat: Faults Major Faults 300 254 Minor Faults 645183 660284 Page ins 493588 486704 Page outs 4960088 4986704 Swap ins 1230 661 Swap outs 9869 6355 Performance is mildly affected because kswapd is no longer doing as much work and the background memory consumer process is getting in the way. Note that kswapd scanned and reclaimed fewer pages as it's less aggressive and overall fewer pages were scanned and reclaimed. Swap in/out is particularly reduced again reflecting kswapd throwing out fewer pages. The slight performance impact is unfortunate here but it looks like a direct result of kswapd being less aggressive. As the bug report is about too many pages being freed by kswapd, it may have to be accepted for now. The second test is a streaming IO benchmark that was previously used by Johannes to show regressions in page reclaim. MICRO traceonly kanyzone User/Sys Time Running Test (seconds) 29.29 28.87 Total Elapsed Time (seconds) 492.18 488.79 VMstat Reclaim Statistics: vmscan Direct reclaims 2128 1460 Direct reclaim pages scanned 2284822 1496067 Direct reclaim pages reclaimed 148919 110937 Kswapd pages scanned 15450014 16202876 Kswapd pages reclaimed 8503697 8537897 Kswapd low wmark quickly 3100 3397 Kswapd high wmark quickly 1860 7243 Kswapd skip congestion_wait 708 801 Pages activated 9635 9573 Pages deactivated 1432 1271 Pages written 223 1130 Total pages scanned 17734836 17698943 Total pages reclaimed 8652616 8648834 %age total pages scanned/reclaimed 48.79% 48.87% %age total pages scanned/written 0.00% 0.01% proc vmstat: Faults Major Faults 165 221 Minor Faults 9655785 9656506 Page ins 3880 7228 Page outs 37692940 37480076 Swap ins 0 69 Swap outs 19 15 Again fewer pages are scanned and reclaimed as expected and this time the test completed faster. Note that kswapd is hitting its watermarks faster (low and high wmark quickly) which I expect is due to kswapd reclaiming fewer pages. I also ran fs-mark, iozone and sysbench but there is nothing interesting to report in the figures. Performance is not significantly changed and the reclaim statistics look reasonable. Tgis patch: When the allocator enters its slow path, kswapd is woken up to balance the node. It continues working until all zones within the node are balanced. For order-0 allocations, this makes perfect sense but for higher orders it can have unintended side-effects. If the zone sizes are imbalanced, kswapd may reclaim heavily within a smaller zone discarding an excessive number of pages. The user-visible behaviour is that kswapd is awake and reclaiming even though plenty of pages are free from a suitable zone. This patch alters the "balance" logic for high-order reclaim allowing kswapd to stop if any suitable zone becomes balanced to reduce the number of pages it reclaims from other zones. kswapd still tries to ensure that order-0 watermarks for all zones are met before sleeping. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Eric B Munson <emunson@mgebm.net> Cc: Simon Kirby <sim@hostway.ca> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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88f5acf8 |
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13-Jan-2011 |
Mel Gorman <mel@csn.ul.ie> |
mm: page allocator: adjust the per-cpu counter threshold when memory is low Commit aa45484 ("calculate a better estimate of NR_FREE_PAGES when memory is low") noted that watermarks were based on the vmstat NR_FREE_PAGES. To avoid synchronization overhead, these counters are maintained on a per-cpu basis and drained both periodically and when a threshold is above a threshold. On large CPU systems, the difference between the estimate and real value of NR_FREE_PAGES can be very high. The system can get into a case where pages are allocated far below the min watermark potentially causing livelock issues. The commit solved the problem by taking a better reading of NR_FREE_PAGES when memory was low. Unfortately, as reported by Shaohua Li this accurate reading can consume a large amount of CPU time on systems with many sockets due to cache line bouncing. This patch takes a different approach. For large machines where counter drift might be unsafe and while kswapd is awake, the per-cpu thresholds for the target pgdat are reduced to limit the level of drift to what should be a safe level. This incurs a performance penalty in heavy memory pressure by a factor that depends on the workload and the machine but the machine should function correctly without accidentally exhausting all memory on a node. There is an additional cost when kswapd wakes and sleeps but the event is not expected to be frequent - in Shaohua's test case, there was one recorded sleep and wake event at least. To ensure that kswapd wakes up, a safe version of zone_watermark_ok() is introduced that takes a more accurate reading of NR_FREE_PAGES when called from wakeup_kswapd, when deciding whether it is really safe to go back to sleep in sleeping_prematurely() and when deciding if a zone is really balanced or not in balance_pgdat(). We are still using an expensive function but limiting how often it is called. When the test case is reproduced, the time spent in the watermark functions is reduced. The following report is on the percentage of time spent cumulatively spent in the functions zone_nr_free_pages(), zone_watermark_ok(), __zone_watermark_ok(), zone_watermark_ok_safe(), zone_page_state_snapshot(), zone_page_state(). vanilla 11.6615% disable-threshold 0.2584% David said: : We had to pull aa454840 "mm: page allocator: calculate a better estimate : of NR_FREE_PAGES when memory is low and kswapd is awake" from 2.6.36 : internally because tests showed that it would cause the machine to stall : as the result of heavy kswapd activity. I merged it back with this fix as : it is pending in the -mm tree and it solves the issue we were seeing, so I : definitely think this should be pushed to -stable (and I would seriously : consider it for 2.6.37 inclusion even at this late date). Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reported-by: Shaohua Li <shaohua.li@intel.com> Reviewed-by: Christoph Lameter <cl@linux.com> Tested-by: Nicolas Bareil <nico@chdir.org> Cc: David Rientjes <rientjes@google.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: <stable@kernel.org> [2.6.37.1, 2.6.36.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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0e093d99 |
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26-Oct-2010 |
Mel Gorman <mel@csn.ul.ie> |
writeback: do not sleep on the congestion queue if there are no congested BDIs or if significant congestion is not being encountered in the current zone If congestion_wait() is called with no BDI congested, the caller will sleep for the full timeout and this may be an unnecessary sleep. This patch adds a wait_iff_congested() that checks congestion and only sleeps if a BDI is congested else, it calls cond_resched() to ensure the caller is not hogging the CPU longer than its quota but otherwise will not sleep. This is aimed at reducing some of the major desktop stalls reported during IO. For example, while kswapd is operating, it calls congestion_wait() but it could just have been reclaiming clean page cache pages with no congestion. Without this patch, it would sleep for a full timeout but after this patch, it'll just call schedule() if it has been on the CPU too long. Similar logic applies to direct reclaimers that are not making enough progress. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ea941f0e |
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26-Oct-2010 |
Michael Rubin <mrubin@google.com> |
writeback: add nr_dirtied and nr_written to /proc/vmstat To help developers and applications gain visibility into writeback behaviour adding two entries to vm_stat_items and /proc/vmstat. This will allow us to track the "written" and "dirtied" counts. # grep nr_dirtied /proc/vmstat nr_dirtied 3747 # grep nr_written /proc/vmstat nr_written 3618 Signed-off-by: Michael Rubin <mrubin@google.com> Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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aa454840 |
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09-Sep-2010 |
Christoph Lameter <cl@linux.com> |
mm: page allocator: calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake Ordinarily watermark checks are based on the vmstat NR_FREE_PAGES as it is cheaper than scanning a number of lists. To avoid synchronization overhead, counter deltas are maintained on a per-cpu basis and drained both periodically and when the delta is above a threshold. On large CPU systems, the difference between the estimated and real value of NR_FREE_PAGES can be very high. If NR_FREE_PAGES is much higher than number of real free page in buddy, the VM can allocate pages below min watermark, at worst reducing the real number of pages to zero. Even if the OOM killer kills some victim for freeing memory, it may not free memory if the exit path requires a new page resulting in livelock. This patch introduces a zone_page_state_snapshot() function (courtesy of Christoph) that takes a slightly more accurate view of an arbitrary vmstat counter. It is used to read NR_FREE_PAGES while kswapd is awake to avoid the watermark being accidentally broken. The estimate is not perfect and may result in cache line bounces but is expected to be lighter than the IPI calls necessary to continually drain the per-cpu counters while kswapd is awake. Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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25edde03 |
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09-Aug-2010 |
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> |
vmscan: kill prev_priority completely Since 2.6.28 zone->prev_priority is unused. Then it can be removed safely. It reduce stack usage slightly. Now I have to say that I'm sorry. 2 years ago, I thought prev_priority can be integrate again, it's useful. but four (or more) times trying haven't got good performance number. Thus I give up such approach. The rest of this changelog is notes on prev_priority and why it existed in the first place and why it might be not necessary any more. This information is based heavily on discussions between Andrew Morton, Rik van Riel and Kosaki Motohiro who is heavily quotes from. Historically prev_priority was important because it determined when the VM would start unmapping PTE pages. i.e. there are no balances of note within the VM, Anon vs File and Mapped vs Unmapped. Without prev_priority, there is a potential risk of unnecessarily increasing minor faults as a large amount of read activity of use-once pages could push mapped pages to the end of the LRU and get unmapped. There is no proof this is still a problem but currently it is not considered to be. Active files are not deactivated if the active file list is smaller than the inactive list reducing the liklihood that file-mapped pages are being pushed off the LRU and referenced executable pages are kept on the active list to avoid them getting pushed out by read activity. Even if it is a problem, prev_priority prev_priority wouldn't works nowadays. First of all, current vmscan still a lot of UP centric code. it expose some weakness on some dozens CPUs machine. I think we need more and more improvement. The problem is, current vmscan mix up per-system-pressure, per-zone-pressure and per-task-pressure a bit. example, prev_priority try to boost priority to other concurrent priority. but if the another task have mempolicy restriction, it is unnecessary, but also makes wrong big latency and exceeding reclaim. per-task based priority + prev_priority adjustment make the emulation of per-system pressure. but it have two issue 1) too rough and brutal emulation 2) we need per-zone pressure, not per-system. Another example, currently DEF_PRIORITY is 12. it mean the lru rotate about 2 cycle (1/4096 + 1/2048 + 1/1024 + .. + 1) before invoking OOM-Killer. but if 10,0000 thrreads enter DEF_PRIORITY reclaim at the same time, the system have higher memory pressure than priority==0 (1/4096*10,000 > 2). prev_priority can't solve such multithreads workload issue. In other word, prev_priority concept assume the sysmtem don't have lots threads." Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michael Rubin <mrubin@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b645bd12 |
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09-Aug-2010 |
Alexander Nevenchannyy <a.nevenchannyy@gmail.com> |
mmzone.h: remove dead prototype get_zone_counts() was dropped from kernel tree, see: http://www.mail-archive.com/mm-commits@vger.kernel.org/msg07313.html but its prototype remains. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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7aac7898 |
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26-May-2010 |
Lee Schermerhorn <lee.schermerhorn@hp.com> |
numa: introduce numa_mem_id()- effective local memory node id Introduce numa_mem_id(), based on generic percpu variable infrastructure to track "nearest node with memory" for archs that support memoryless nodes. Define API in <linux/topology.h> when CONFIG_HAVE_MEMORYLESS_NODES defined, else stubs. Architectures will define HAVE_MEMORYLESS_NODES if/when they support them. Archs can override definitions of: numa_mem_id() - returns node number of "local memory" node set_numa_mem() - initialize [this cpus'] per cpu variable 'numa_mem' cpu_to_mem() - return numa_mem for specified cpu; may be used as lvalue Generic initialization of 'numa_mem' occurs in __build_all_zonelists(). This will initialize the boot cpu at boot time, and all cpus on change of numa_zonelist_order, or when node or memory hot-plug requires zonelist rebuild. Archs that support memoryless nodes will need to initialize 'numa_mem' for secondary cpus as they're brought on-line. [akpm@linux-foundation.org: fix build] Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Christoph Lameter <cl@linux-foundation.org> Cc: Tejun Heo <tj@kernel.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Nick Piggin <npiggin@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Eric Whitney <eric.whitney@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4eaf3f64 |
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24-May-2010 |
Haicheng Li <haicheng.li@linux.intel.com> |
mem-hotplug: fix potential race while building zonelist for new populated zone Add global mutex zonelists_mutex to fix the possible race: CPU0 CPU1 CPU2 (1) zone->present_pages += online_pages; (2) build_all_zonelists(); (3) alloc_page(); (4) free_page(); (5) build_all_zonelists(); (6) __build_all_zonelists(); (7) zone->pageset = alloc_percpu(); In step (3,4), zone->pageset still points to boot_pageset, so bad things may happen if 2+ nodes are in this state. Even if only 1 node is accessing the boot_pageset, (3) may still consume too much memory to fail the memory allocations in step (7). Besides, atomic operation ensures alloc_percpu() in step (7) will never fail since there is a new fresh memory block added in step(6). [haicheng.li@linux.intel.com: hold zonelists_mutex when build_all_zonelists] Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: Andi Kleen <andi.kleen@intel.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1f522509 |
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24-May-2010 |
Haicheng Li <haicheng.li@linux.intel.com> |
mem-hotplug: avoid multiple zones sharing same boot strapping boot_pageset For each new populated zone of hotadded node, need to update its pagesets with dynamically allocated per_cpu_pageset struct for all possible CPUs: 1) Detach zone->pageset from the shared boot_pageset at end of __build_all_zonelists(). 2) Use mutex to protect zone->pageset when it's still shared in onlined_pages() Otherwises, multiple zones of different nodes would share same boot strapping boot_pageset for same CPU, which will finally cause below kernel panic: ------------[ cut here ]------------ kernel BUG at mm/page_alloc.c:1239! invalid opcode: 0000 [#1] SMP ... Call Trace: [<ffffffff811300c1>] __alloc_pages_nodemask+0x131/0x7b0 [<ffffffff81162e67>] alloc_pages_current+0x87/0xd0 [<ffffffff81128407>] __page_cache_alloc+0x67/0x70 [<ffffffff811325f0>] __do_page_cache_readahead+0x120/0x260 [<ffffffff81132751>] ra_submit+0x21/0x30 [<ffffffff811329c6>] ondemand_readahead+0x166/0x2c0 [<ffffffff81132ba0>] page_cache_async_readahead+0x80/0xa0 [<ffffffff8112a0e4>] generic_file_aio_read+0x364/0x670 [<ffffffff81266cfa>] nfs_file_read+0xca/0x130 [<ffffffff8117b20a>] do_sync_read+0xfa/0x140 [<ffffffff8117bf75>] vfs_read+0xb5/0x1a0 [<ffffffff8117c151>] sys_read+0x51/0x80 [<ffffffff8103c032>] system_call_fastpath+0x16/0x1b RIP [<ffffffff8112ff13>] get_page_from_freelist+0x883/0x900 RSP <ffff88000d1e78a8> ---[ end trace 4bda28328b9990db ] [akpm@linux-foundation.org: merge fix] Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: Andi Kleen <andi.kleen@intel.com> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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0faa5638 |
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24-May-2010 |
Marcelo Roberto Jimenez <mroberto@cpti.cetuc.puc-rio.br> |
mm: fix NR_SECTION_ROOTS == 0 when using using sparsemem extreme. Got this while compiling for ARM/SA1100: mm/sparse.c: In function '__section_nr': mm/sparse.c:135: warning: 'root' is used uninitialized in this function This patch follows Russell King's suggestion for a new calculation for NR_SECTION_ROOTS. Thanks also to Sergei Shtylyov for pointing out the existence of the macro DIV_ROUND_UP. Atsushi Nemoto observed: : This fix doesn't just silence the warning - it fixes a real problem. : : Without this fix, mem_section[] might have 0 size so mem_section[0] : will share other variable area. For example, I got: : : c030c700 b __warned.16478 : c030c700 B mem_section : c030c701 b __warned.16483 : : This might cause very strange behavior. Your patch actually fixes it. Signed-off-by: Marcelo Roberto Jimenez <mroberto@cpti.cetuc.puc-rio.br> Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Sergei Shtylyov <sshtylyov@mvista.com> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4f92e258 |
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24-May-2010 |
Mel Gorman <mel@csn.ul.ie> |
mm: compaction: defer compaction using an exponential backoff when compaction fails The fragmentation index may indicate that a failure is due to external fragmentation but after a compaction run completes, it is still possible for an allocation to fail. There are two obvious reasons as to why o Page migration cannot move all pages so fragmentation remains o A suitable page may exist but watermarks are not met In the event of compaction followed by an allocation failure, this patch defers further compaction in the zone (1 << compact_defer_shift) times. If the next compaction attempt also fails, compact_defer_shift is increased up to a maximum of 6. If compaction succeeds, the defer counters are reset again. The zone that is deferred is the first zone in the zonelist - i.e. the preferred zone. To defer compaction in the other zones, the information would need to be stored in the zonelist or implemented similar to the zonelist_cache. This would impact the fast-paths and is not justified at this time. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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93e4a89a |
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05-Mar-2010 |
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> |
mm: restore zone->all_unreclaimable to independence word commit e815af95 ("change all_unreclaimable zone member to flags") changed all_unreclaimable member to bit flag. But it had an undesireble side effect. free_one_page() is one of most hot path in linux kernel and increasing atomic ops in it can reduce kernel performance a bit. Thus, this patch revert such commit partially. at least all_unreclaimable shouldn't share memory word with other zone flags. [akpm@linux-foundation.org: fix patch interaction] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Huang Shijie <shijie8@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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43cf38eb |
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01-Feb-2010 |
Tejun Heo <tj@kernel.org> |
percpu: add __percpu sparse annotations to core kernel subsystems Add __percpu sparse annotations to core subsystems. These annotations are to make sparse consider percpu variables to be in a different address space and warn if accessed without going through percpu accessors. This patch doesn't affect normal builds. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-mm@kvack.org Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Eric Biederman <ebiederm@xmission.com>
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08677214 |
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10-Feb-2010 |
Yinghai Lu <yinghai@kernel.org> |
x86: Make 64 bit use early_res instead of bootmem before slab Finally we can use early_res to replace bootmem for x86_64 now. Still can use CONFIG_NO_BOOTMEM to enable it or not. -v2: fix 32bit compiling about MAX_DMA32_PFN -v3: folded bug fix from LKML message below Signed-off-by: Yinghai Lu <yinghai@kernel.org> LKML-Reference: <4B747239.4070907@kernel.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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2a61aa40 |
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11-Dec-2009 |
Adam Buchbinder <adam.buchbinder@gmail.com> |
Fix misspellings of "invocation" in comments. Some comments misspell "invocation"; this fixes them. No code changes. Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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99dcc3e5 |
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04-Jan-2010 |
Christoph Lameter <cl@linux-foundation.org> |
this_cpu: Page allocator conversion Use the per cpu allocator functionality to avoid per cpu arrays in struct zone. This drastically reduces the size of struct zone for systems with large amounts of processors and allows placement of critical variables of struct zone in one cacheline even on very large systems. Another effect is that the pagesets of one processor are placed near one another. If multiple pagesets from different zones fit into one cacheline then additional cacheline fetches can be avoided on the hot paths when allocating memory from multiple zones. Bootstrap becomes simpler if we use the same scheme for UP, SMP, NUMA. #ifdefs are reduced and we can drop the zone_pcp macro. Hotplug handling is also simplified since cpu alloc can bring up and shut down cpu areas for a specific cpu as a whole. So there is no need to allocate or free individual pagesets. V7-V8: - Explain chicken egg dilemmna with percpu allocator. V4-V5: - Fix up cases where per_cpu_ptr is called before irq disable - Integrate the bootstrap logic that was separate before. tj: Build failure in pageset_cpuup_callback() due to missing ret variable fixed. Reviewed-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: Tejun Heo <tj@kernel.org>
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01fc0ac1 |
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19-Apr-2009 |
Sam Ravnborg <sam@ravnborg.org> |
kbuild: move bounds.h to include/generated Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Michal Marek <mmarek@suse.cz>
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8d65af78 |
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23-Sep-2009 |
Alexey Dobriyan <adobriyan@gmail.com> |
sysctl: remove "struct file *" argument of ->proc_handler It's unused. It isn't needed -- read or write flag is already passed and sysctl shouldn't care about the rest. It _was_ used in two places at arch/frv for some reason. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "David S. Miller" <davem@davemloft.net> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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5f8dcc21 |
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21-Sep-2009 |
Mel Gorman <mel@csn.ul.ie> |
page-allocator: split per-cpu list into one-list-per-migrate-type The following two patches remove searching in the page allocator fast-path by maintaining multiple free-lists in the per-cpu structure. At the time the search was introduced, increasing the per-cpu structures would waste a lot of memory as per-cpu structures were statically allocated at compile-time. This is no longer the case. The patches are as follows. They are based on mmotm-2009-08-27. Patch 1 adds multiple lists to struct per_cpu_pages, one per migratetype that can be stored on the PCP lists. Patch 2 notes that the pcpu drain path check empty lists multiple times. The patch reduces the number of checks by maintaining a count of free lists encountered. Lists containing pages will then free multiple pages in batch The patches were tested with kernbench, netperf udp/tcp, hackbench and sysbench. The netperf tests were not bound to any CPU in particular and were run such that the results should be 99% confidence that the reported results are within 1% of the estimated mean. sysbench was run with a postgres background and read-only tests. Similar to netperf, it was run multiple times so that it's 99% confidence results are within 1%. The patches were tested on x86, x86-64 and ppc64 as x86: Intel Pentium D 3GHz with 8G RAM (no-brand machine) kernbench - No significant difference, variance well within noise netperf-udp - 1.34% to 2.28% gain netperf-tcp - 0.45% to 1.22% gain hackbench - Small variances, very close to noise sysbench - Very small gains x86-64: AMD Phenom 9950 1.3GHz with 8G RAM (no-brand machine) kernbench - No significant difference, variance well within noise netperf-udp - 1.83% to 10.42% gains netperf-tcp - No conclusive until buffer >= PAGE_SIZE 4096 +15.83% 8192 + 0.34% (not significant) 16384 + 1% hackbench - Small gains, very close to noise sysbench - 0.79% to 1.6% gain ppc64: PPC970MP 2.5GHz with 10GB RAM (it's a terrasoft powerstation) kernbench - No significant difference, variance well within noise netperf-udp - 2-3% gain for almost all buffer sizes tested netperf-tcp - losses on small buffers, gains on larger buffers possibly indicates some bad caching effect. hackbench - No significant difference sysbench - 2-4% gain This patch: Currently the per-cpu page allocator searches the PCP list for pages of the correct migrate-type to reduce the possibility of pages being inappropriate placed from a fragmentation perspective. This search is potentially expensive in a fast-path and undesirable. Splitting the per-cpu list into multiple lists increases the size of a per-cpu structure and this was potentially a major problem at the time the search was introduced. These problem has been mitigated as now only the necessary number of structures is allocated for the running system. This patch replaces a list search in the per-cpu allocator with one list per migrate type. The potential snag with this approach is when bulk freeing pages. We round-robin free pages based on migrate type which has little bearing on the cache hotness of the page and potentially checks empty lists repeatedly in the event the majority of PCP pages are of one type. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Nick Piggin <npiggin@suse.de> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
f8629631 |
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21-Sep-2009 |
Wu Fengguang <fengguang.wu@intel.com> |
mm: do batched scans for mem_cgroup For mem_cgroup, shrink_zone() may call shrink_list() with nr_to_scan=1, in which case shrink_list() _still_ calls isolate_pages() with the much larger SWAP_CLUSTER_MAX. It effectively scales up the inactive list scan rate by up to 32 times. For example, with 16k inactive pages and DEF_PRIORITY=12, (16k >> 12)=4. So when shrink_zone() expects to scan 4 pages in the active/inactive list, the active list will be scanned 4 pages, while the inactive list will be (over) scanned SWAP_CLUSTER_MAX=32 pages in effect. And that could break the balance between the two lists. It can further impact the scan of anon active list, due to the anon active/inactive ratio rebalance logic in balance_pgdat()/shrink_zone(): inactive anon list over scanned => inactive_anon_is_low() == TRUE => shrink_active_list() => active anon list over scanned So the end result may be - anon inactive => over scanned - anon active => over scanned (maybe not as much) - file inactive => over scanned - file active => under scanned (relatively) The accesses to nr_saved_scan are not lock protected and so not 100% accurate, however we can tolerate small errors and the resulted small imbalanced scan rates between zones. Cc: Rik van Riel <riel@redhat.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a731286d |
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21-Sep-2009 |
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> |
mm: vmstat: add isolate pages If the system is running a heavy load of processes then concurrent reclaim can isolate a large number of pages from the LRU. /proc/vmstat and the output generated for an OOM do not show how many pages were isolated. This has been observed during process fork bomb testing (mstctl11 in LTP). This patch shows the information about isolated pages. Reproduced via: ----------------------- % ./hackbench 140 process 1000 => OOM occur active_anon:146 inactive_anon:0 isolated_anon:49245 active_file:79 inactive_file:18 isolated_file:113 unevictable:0 dirty:0 writeback:0 unstable:0 buffer:39 free:370 slab_reclaimable:309 slab_unreclaimable:5492 mapped:53 shmem:15 pagetables:28140 bounce:0 Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
4b02108a |
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21-Sep-2009 |
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> |
mm: oom analysis: add shmem vmstat Recently we encountered OOM problems due to memory use of the GEM cache. Generally a large amuont of Shmem/Tmpfs pages tend to create a memory shortage problem. We often use the following calculation to determine the amount of shmem pages: shmem = NR_ACTIVE_ANON + NR_INACTIVE_ANON - NR_ANON_PAGES however the expression does not consider isolated and mlocked pages. This patch adds explicit accounting for pages used by shmem and tmpfs. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Acked-by: Wu Fengguang <fengguang.wu@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
c6a7f572 |
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21-Sep-2009 |
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> |
mm: oom analysis: Show kernel stack usage in /proc/meminfo and OOM log output The amount of memory allocated to kernel stacks can become significant and cause OOM conditions. However, we do not display the amount of memory consumed by stacks. Add code to display the amount of memory used for stacks in /proc/meminfo. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
68377659 |
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16-Jun-2009 |
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> |
mm: remove CONFIG_UNEVICTABLE_LRU config option Currently, nobody wants to turn UNEVICTABLE_LRU off. Thus this configurability is unnecessary. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Andi Kleen <andi@firstfloor.org> Acked-by: Minchan Kim <minchan.kim@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Rik van Riel <riel@redhat.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
6e08a369 |
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16-Jun-2009 |
Wu Fengguang <fengguang.wu@intel.com> |
vmscan: cleanup the scan batching code The vmscan batching logic is twisting. Move it into a standalone function nr_scan_try_batch() and document it. No behavior change. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Christoph Lameter <cl@linux-foundation.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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41858966 |
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16-Jun-2009 |
Mel Gorman <mel@csn.ul.ie> |
page allocator: use allocation flags as an index to the zone watermark ALLOC_WMARK_MIN, ALLOC_WMARK_LOW and ALLOC_WMARK_HIGH determin whether pages_min, pages_low or pages_high is used as the zone watermark when allocating the pages. Two branches in the allocator hotpath determine which watermark to use. This patch uses the flags as an array index into a watermark array that is indexed with WMARK_* defines accessed via helpers. All call sites that use zone->pages_* are updated to use the helpers for accessing the values and the array offsets for setting. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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49255c61 |
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16-Jun-2009 |
Mel Gorman <mel@csn.ul.ie> |
page allocator: move check for disabled anti-fragmentation out of fastpath On low-memory systems, anti-fragmentation gets disabled as there is nothing it can do and it would just incur overhead shuffling pages between lists constantly. Currently the check is made in the free page fast path for every page. This patch moves it to a slow path. On machines with low memory, there will be small amount of additional overhead as pages get shuffled between lists but it should quickly settle. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
eb33575c |
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13-May-2009 |
Mel Gorman <mel@csn.ul.ie> |
[ARM] Double check memmap is actually valid with a memmap has unexpected holes V2 pfn_valid() is meant to be able to tell if a given PFN has valid memmap associated with it or not. In FLATMEM, it is expected that holes always have valid memmap as long as there is valid PFNs either side of the hole. In SPARSEMEM, it is assumed that a valid section has a memmap for the entire section. However, ARM and maybe other embedded architectures in the future free memmap backing holes to save memory on the assumption the memmap is never used. The page_zone linkages are then broken even though pfn_valid() returns true. A walker of the full memmap must then do this additional check to ensure the memmap they are looking at is sane by making sure the zone and PFN linkages are still valid. This is expensive, but walkers of the full memmap are extremely rare. This was caught before for FLATMEM and hacked around but it hits again for SPARSEMEM because the page_zone linkages can look ok where the PFN linkages are totally screwed. This looks like a hatchet job but the reality is that any clean solution would end up consumning all the memory saved by punching these unexpected holes in the memmap. For example, we tried marking the memmap within the section invalid but the section size exceeds the size of the hole in most cases so pfn_valid() starts returning false where valid memmap exists. Shrinking the size of the section would increase memory consumption offsetting the gains. This patch identifies when an architecture is punching unexpected holes in the memmap that the memory model cannot automatically detect and sets ARCH_HAS_HOLES_MEMORYMODEL. At the moment, this is restricted to EP93xx which is the model sub-architecture this has been reported on but may expand later. When set, walkers of the full memmap must call memmap_valid_within() for each PFN and passing in what it expects the page and zone to be for that PFN. If it finds the linkages to be broken, it assumes the memmap is invalid for that PFN. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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ee99c71c |
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31-Mar-2009 |
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> |
mm: introduce for_each_populated_zone() macro Impact: cleanup In almost cases, for_each_zone() is used with populated_zone(). It's because almost function doesn't need memoryless node information. Therefore, for_each_populated_zone() can help to make code simplify. This patch has no functional change. [akpm@linux-foundation.org: small cleanup] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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082edb7b |
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13-Mar-2009 |
Rusty Russell <rusty@rustcorp.com.au> |
numa, cpumask: move numa_node_id default implementation to topology.h Impact: cleanup, potential bugfix Not sure what changed to expose this, but clearly that numa_node_id() doesn't belong in mmzone.h (the inline in gfp.h is probably overkill, too). In file included from include/linux/topology.h:34, from arch/x86/mm/numa.c:2: /home/rusty/patches-cpumask/linux-2.6/arch/x86/include/asm/topology.h:64:1: warning: "numa_node_id" redefined In file included from include/linux/topology.h:32, from arch/x86/mm/numa.c:2: include/linux/mmzone.h:770:1: warning: this is the location of the previous definition Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Mike Travis <travis@sgi.com> LKML-Reference: <200903132343.37661.rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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cc2559bc |
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18-Feb-2009 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
mm: fix memmap init for handling memory hole Now, early_pfn_in_nid(PFN, NID) may returns false if PFN is a hole. and memmap initialization was not done. This was a trouble for sparc boot. To fix this, the PFN should be initialized and marked as PG_reserved. This patch changes early_pfn_in_nid() return true if PFN is a hole. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reported-by: David Miller <davem@davemlloft.net> Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: <stable@kernel.org> [2.6.25.x, 2.6.26.x, 2.6.27.x, 2.6.28.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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6e901571 |
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07-Jan-2009 |
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> |
mm: introduce zone_reclaim struct Add zone_reclam_stat struct for later enhancement. A later patch uses this. This patch doesn't any behavior change (yet). Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Hugh Dickins <hugh@veritas.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
52d4b9ac |
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18-Oct-2008 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
memcg: allocate all page_cgroup at boot Allocate all page_cgroup at boot and remove page_cgroup poitner from struct page. This patch adds an interface as struct page_cgroup *lookup_page_cgroup(struct page*) All FLATMEM/DISCONTIGMEM/SPARSEMEM and MEMORY_HOTPLUG is supported. Remove page_cgroup pointer reduces the amount of memory by - 4 bytes per PAGE_SIZE. - 8 bytes per PAGE_SIZE if memory controller is disabled. (even if configured.) On usual 8GB x86-32 server, this saves 8MB of NORMAL_ZONE memory. On my x86-64 server with 48GB of memory, this saves 96MB of memory. I think this reduction makes sense. By pre-allocation, kmalloc/kfree in charge/uncharge are removed. This means - we're not necessary to be afraid of kmalloc faiulre. (this can happen because of gfp_mask type.) - we can avoid calling kmalloc/kfree. - we can avoid allocating tons of small objects which can be fragmented. - we can know what amount of memory will be used for this extra-lru handling. I added printk message as "allocated %ld bytes of page_cgroup" "please try cgroup_disable=memory option if you don't want" maybe enough informative for users. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
5344b7e6 |
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18-Oct-2008 |
Nick Piggin <npiggin@suse.de> |
vmstat: mlocked pages statistics Add NR_MLOCK zone page state, which provides a (conservative) count of mlocked pages (actually, the number of mlocked pages moved off the LRU). Reworked by lts to fit in with the modified mlock page support in the Reclaim Scalability series. [kosaki.motohiro@jp.fujitsu.com: fix incorrect Mlocked field of /proc/meminfo] [lee.schermerhorn@hp.com: mlocked-pages: add event counting with statistics] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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894bc310 |
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18-Oct-2008 |
Lee Schermerhorn <Lee.Schermerhorn@hp.com> |
Unevictable LRU Infrastructure When the system contains lots of mlocked or otherwise unevictable pages, the pageout code (kswapd) can spend lots of time scanning over these pages. Worse still, the presence of lots of unevictable pages can confuse kswapd into thinking that more aggressive pageout modes are required, resulting in all kinds of bad behaviour. Infrastructure to manage pages excluded from reclaim--i.e., hidden from vmscan. Based on a patch by Larry Woodman of Red Hat. Reworked to maintain "unevictable" pages on a separate per-zone LRU list, to "hide" them from vmscan. Kosaki Motohiro added the support for the memory controller unevictable lru list. Pages on the unevictable list have both PG_unevictable and PG_lru set. Thus, PG_unevictable is analogous to and mutually exclusive with PG_active--it specifies which LRU list the page is on. The unevictable infrastructure is enabled by a new mm Kconfig option [CONFIG_]UNEVICTABLE_LRU. A new function 'page_evictable(page, vma)' in vmscan.c tests whether or not a page may be evictable. Subsequent patches will add the various !evictable tests. We'll want to keep these tests light-weight for use in shrink_active_list() and, possibly, the fault path. To avoid races between tasks putting pages [back] onto an LRU list and tasks that might be moving the page from non-evictable to evictable state, the new function 'putback_lru_page()' -- inverse to 'isolate_lru_page()' -- tests the "evictability" of a page after placing it on the LRU, before dropping the reference. If the page has become unevictable, putback_lru_page() will redo the 'putback', thus moving the page to the unevictable list. This way, we avoid "stranding" evictable pages on the unevictable list. [akpm@linux-foundation.org: fix fallout from out-of-order merge] [riel@redhat.com: fix UNEVICTABLE_LRU and !PROC_PAGE_MONITOR build] [nishimura@mxp.nes.nec.co.jp: remove redundant mapping check] [kosaki.motohiro@jp.fujitsu.com: unevictable-lru-infrastructure: putback_lru_page()/unevictable page handling rework] [kosaki.motohiro@jp.fujitsu.com: kill unnecessary lock_page() in vmscan.c] [kosaki.motohiro@jp.fujitsu.com: revert migration change of unevictable lru infrastructure] [kosaki.motohiro@jp.fujitsu.com: revert to unevictable-lru-infrastructure-kconfig-fix.patch] [kosaki.motohiro@jp.fujitsu.com: restore patch failure of vmstat-unevictable-and-mlocked-pages-vm-events.patch] Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Debugged-by: Benjamin Kidwell <benjkidwell@yahoo.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
556adecb |
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18-Oct-2008 |
Rik van Riel <riel@redhat.com> |
vmscan: second chance replacement for anonymous pages We avoid evicting and scanning anonymous pages for the most part, but under some workloads we can end up with most of memory filled with anonymous pages. At that point, we suddenly need to clear the referenced bits on all of memory, which can take ages on very large memory systems. We can reduce the maximum number of pages that need to be scanned by not taking the referenced state into account when deactivating an anonymous page. After all, every anonymous page starts out referenced, so why check? If an anonymous page gets referenced again before it reaches the end of the inactive list, we move it back to the active list. To keep the maximum amount of necessary work reasonable, we scale the active to inactive ratio with the size of memory, using the formula active:inactive ratio = sqrt(memory in GB * 10). Kswapd CPU use now seems to scale by the amount of pageout bandwidth, instead of by the amount of memory present in the system. [kamezawa.hiroyu@jp.fujitsu.com: fix OOM with memcg] [kamezawa.hiroyu@jp.fujitsu.com: memcg: lru scan fix] Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
4f98a2fe |
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18-Oct-2008 |
Rik van Riel <riel@redhat.com> |
vmscan: split LRU lists into anon & file sets Split the LRU lists in two, one set for pages that are backed by real file systems ("file") and one for pages that are backed by memory and swap ("anon"). The latter includes tmpfs. The advantage of doing this is that the VM will not have to scan over lots of anonymous pages (which we generally do not want to swap out), just to find the page cache pages that it should evict. This patch has the infrastructure and a basic policy to balance how much we scan the anon lists and how much we scan the file lists. The big policy changes are in separate patches. [lee.schermerhorn@hp.com: collect lru meminfo statistics from correct offset] [kosaki.motohiro@jp.fujitsu.com: prevent incorrect oom under split_lru] [kosaki.motohiro@jp.fujitsu.com: fix pagevec_move_tail() doesn't treat unevictable page] [hugh@veritas.com: memcg swapbacked pages active] [hugh@veritas.com: splitlru: BDI_CAP_SWAP_BACKED] [akpm@linux-foundation.org: fix /proc/vmstat units] [nishimura@mxp.nes.nec.co.jp: memcg: fix handling of shmem migration] [kosaki.motohiro@jp.fujitsu.com: adjust Quicklists field of /proc/meminfo] [kosaki.motohiro@jp.fujitsu.com: fix style issue of get_scan_ratio()] Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
b69408e8 |
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18-Oct-2008 |
Christoph Lameter <cl@linux-foundation.org> |
vmscan: Use an indexed array for LRU variables Currently we are defining explicit variables for the inactive and active list. An indexed array can be more generic and avoid repeating similar code in several places in the reclaim code. We are saving a few bytes in terms of code size: Before: text data bss dec hex filename 4097753 573120 4092484 8763357 85b7dd vmlinux After: text data bss dec hex filename 4097729 573120 4092484 8763333 85b7c5 vmlinux Having an easy way to add new lru lists may ease future work on the reclaim code. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
5bead2a0 |
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13-Sep-2008 |
Mel Gorman <mel@csn.ul.ie> |
mm: mark the correct zone as full when scanning zonelists The iterator for_each_zone_zonelist() uses a struct zoneref *z cursor when scanning zonelists to keep track of where in the zonelist it is. The zoneref that is returned corresponds to the the next zone that is to be scanned, not the current one. It was intended to be treated as an opaque list. When the page allocator is scanning a zonelist, it marks elements in the zonelist corresponding to zones that are temporarily full. As the zonelist is being updated, it uses the cursor here; if (NUMA_BUILD) zlc_mark_zone_full(zonelist, z); This is intended to prevent rescanning in the near future but the zoneref cursor does not correspond to the zone that has been found to be full. This is an easy misunderstanding to make so this patch corrects the problem by changing zoneref cursor to be the current zone being scanned instead of the next one. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: <stable@kernel.org> [2.6.26.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
12d15f0d |
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23-May-2008 |
Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp> |
for_each_online_pgdat(): kerneldoc fix for_each_pgdat() was renamed to for_each_online_pgdat() and kerneldoc comments should be updated accordingly. Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
735643ee |
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30-Apr-2008 |
Robert P. J. Day <rpjday@crashcourse.ca> |
Remove "#ifdef __KERNEL__" checks from unexported headers Remove the "#ifdef __KERNEL__" tests from unexported header files in linux/include whose entire contents are wrapped in that preprocessor test. Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
fc3ba692 |
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30-Apr-2008 |
Miklos Szeredi <mszeredi@suse.cz> |
mm: Add NR_WRITEBACK_TEMP counter Fuse will use temporary buffers to write back dirty data from memory mappings (normal writes are done synchronously). This is needed, because there cannot be any guarantee about the time in which a write will complete. By using temporary buffers, from the MM's point if view the page is written back immediately. If the writeout was due to memory pressure, this effectively migrates data from a full zone to a less full zone. This patch adds a new counter (NR_WRITEBACK_TEMP) for the number of pages used as temporary buffers. [Lee.Schermerhorn@hp.com: add vmstat_text for NR_WRITEBACK_TEMP] Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
04753278 |
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28-Apr-2008 |
Yasunori Goto <y-goto@jp.fujitsu.com> |
memory hotplug: register section/node id to free This patch set is to free pages which is allocated by bootmem for memory-hotremove. Some structures of memory management are allocated by bootmem. ex) memmap, etc. To remove memory physically, some of them must be freed according to circumstance. This patch set makes basis to free those pages, and free memmaps. Basic my idea is using remain members of struct page to remember information of users of bootmem (section number or node id). When the section is removing, kernel can confirm it. By this information, some issues can be solved. 1) When the memmap of removing section is allocated on other section by bootmem, it should/can be free. 2) When the memmap of removing section is allocated on the same section, it shouldn't be freed. Because the section has to be logical memory offlined already and all pages must be isolated against page allocater. If it is freed, page allocator may use it which will be removed physically soon. 3) When removing section has other section's memmap, kernel will be able to show easily which section should be removed before it for user. (Not implemented yet) 4) When the above case 2), the page isolation will be able to check and skip memmap's page when logical memory offline (offline_pages()). Current page isolation code fails in this case because this page is just reserved page and it can't distinguish this pages can be removed or not. But, it will be able to do by this patch. (Not implemented yet.) 5) The node information like pgdat has similar issues. But, this will be able to be solved too by this. (Not implemented yet, but, remembering node id in the pages.) Fortunately, current bootmem allocator just keeps PageReserved flags, and doesn't use any other members of page struct. The users of bootmem doesn't use them too. This patch: This is to register information which is node or section's id. Kernel can distinguish which node/section uses the pages allcated by bootmem. This is basis for hot-remove sections or nodes. Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Cc: Yinghai Lu <yhlu.kernel@gmail.com> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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97965478 |
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28-Apr-2008 |
Christoph Lameter <clameter@sgi.com> |
mm: Get rid of __ZONE_COUNT It was used to compensate because MAX_NR_ZONES was not available to the #ifdefs. Export MAX_NR_ZONES via the new mechanism and get rid of __ZONE_COUNT. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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9223b419 |
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28-Apr-2008 |
Christoph Lameter <clameter@sgi.com> |
pageflags: get rid of FLAGS_RESERVED NR_PAGEFLAGS specifies the number of page flags we are using. From that we can calculate the number of bits leftover that can be used for zone, node (and maybe the sections id). There is no need anymore for FLAGS_RESERVED if we use NR_PAGEFLAGS. Use the new methods to make NR_PAGEFLAGS available via the preprocessor. NR_PAGEFLAGS is used to calculate field boundaries in the page flags fields. These field widths have to be available to the preprocessor. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: David Miller <davem@davemloft.net> Cc: Andy Whitcroft <apw@shadowen.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
b4544568 |
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28-Apr-2008 |
Andrew Morton <akpm@linux-foundation.org> |
mm: make early_pfn_to_nid() a C function Fix this (sparc64) mm/sparse-vmemmap.c: In function `vmemmap_verify': mm/sparse-vmemmap.c:64: warning: unused variable `pfn' by switching to a C function which touches its arg. (reason 3,555 why macros are bad) Also, the `nid' arg was misnamed. Reviewed-by: Christoph Lameter <clameter@sgi.com> Acked-by: Andy Whitcroft <apw@shadowen.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andi Kleen <ak@suse.de> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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19770b32 |
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28-Apr-2008 |
Mel Gorman <mel@csn.ul.ie> |
mm: filter based on a nodemask as well as a gfp_mask The MPOL_BIND policy creates a zonelist that is used for allocations controlled by that mempolicy. As the per-node zonelist is already being filtered based on a zone id, this patch adds a version of __alloc_pages() that takes a nodemask for further filtering. This eliminates the need for MPOL_BIND to create a custom zonelist. A positive benefit of this is that allocations using MPOL_BIND now use the local node's distance-ordered zonelist instead of a custom node-id-ordered zonelist. I.e., pages will be allocated from the closest allowed node with available memory. [Lee.Schermerhorn@hp.com: Mempolicy: update stale documentation and comments] [Lee.Schermerhorn@hp.com: Mempolicy: make dequeue_huge_page_vma() obey MPOL_BIND nodemask] [Lee.Schermerhorn@hp.com: Mempolicy: make dequeue_huge_page_vma() obey MPOL_BIND nodemask rework] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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dd1a239f |
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28-Apr-2008 |
Mel Gorman <mel@csn.ul.ie> |
mm: have zonelist contains structs with both a zone pointer and zone_idx Filtering zonelists requires very frequent use of zone_idx(). This is costly as it involves a lookup of another structure and a substraction operation. As the zone_idx is often required, it should be quickly accessible. The node idx could also be stored here if it was found that accessing zone->node is significant which may be the case on workloads where nodemasks are heavily used. This patch introduces a struct zoneref to store a zone pointer and a zone index. The zonelist then consists of an array of these struct zonerefs which are looked up as necessary. Helpers are given for accessing the zone index as well as the node index. [kamezawa.hiroyu@jp.fujitsu.com: Suggested struct zoneref instead of embedding information in pointers] [hugh@veritas.com: mm-have-zonelist: fix memcg ooms] [hugh@veritas.com: just return do_try_to_free_pages] [hugh@veritas.com: do_try_to_free_pages gfp_mask redundant] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Christoph Lameter <clameter@sgi.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <clameter@sgi.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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54a6eb5c |
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28-Apr-2008 |
Mel Gorman <mel@csn.ul.ie> |
mm: use two zonelist that are filtered by GFP mask Currently a node has two sets of zonelists, one for each zone type in the system and a second set for GFP_THISNODE allocations. Based on the zones allowed by a gfp mask, one of these zonelists is selected. All of these zonelists consume memory and occupy cache lines. This patch replaces the multiple zonelists per-node with two zonelists. The first contains all populated zones in the system, ordered by distance, for fallback allocations when the target/preferred node has no free pages. The second contains all populated zones in the node suitable for GFP_THISNODE allocations. An iterator macro is introduced called for_each_zone_zonelist() that interates through each zone allowed by the GFP flags in the selected zonelist. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <clameter@sgi.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ddc81ed2 |
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28-Apr-2008 |
Harvey Harrison <harvey.harrison@gmail.com> |
remove sparse warning for mmzone.h include/linux/mmzone.h:640:22: warning: potentially expensive pointer subtraction Calculate the offset into the node_zones array rather than the index using casts to (char *) and comparing against the index * sizeof(struct zone). On X86_32 this saves a sar, but code size increases by one byte per is_highmem() use due to 32-bit cmps rather than 16 bit cmps. Before: 207: 2b 80 8c 07 00 00 sub 0x78c(%eax),%eax 20d: c1 f8 0b sar $0xb,%eax 210: 83 f8 02 cmp $0x2,%eax 213: 74 16 je 22b <kmap_atomic_prot+0x144> 215: 83 f8 03 cmp $0x3,%eax 218: 0f 85 8f 00 00 00 jne 2ad <kmap_atomic_prot+0x1c6> 21e: 83 3d 00 00 00 00 02 cmpl $0x2,0x0 225: 0f 85 82 00 00 00 jne 2ad <kmap_atomic_prot+0x1c6> 22b: 64 a1 00 00 00 00 mov %fs:0x0,%eax After: 207: 2b 80 8c 07 00 00 sub 0x78c(%eax),%eax 20d: 3d 00 10 00 00 cmp $0x1000,%eax 212: 74 18 je 22c <kmap_atomic_prot+0x145> 214: 3d 00 18 00 00 cmp $0x1800,%eax 219: 0f 85 8f 00 00 00 jne 2ae <kmap_atomic_prot+0x1c7> 21f: 83 3d 00 00 00 00 02 cmpl $0x2,0x0 226: 0f 85 82 00 00 00 jne 2ae <kmap_atomic_prot+0x1c7> 22c: 64 a1 00 00 00 00 mov %fs:0x0,%eax [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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218ff137 |
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21-Apr-2008 |
Johannes Weiner <hannes@saeurebad.de> |
Remove unused MAX_NODES_SHIFT MAX_NODES_SHIFT is not referenced anywhere in the tree, so dump it. Signed-off-by: Johannes Weiner <hannes@saeurebad.de> Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
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3dfa5721 |
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04-Feb-2008 |
Christoph Lameter <clameter@sgi.com> |
Page allocator: get rid of the list of cold pages We have repeatedly discussed if the cold pages still have a point. There is one way to join the two lists: Use a single list and put the cold pages at the end and the hot pages at the beginning. That way a single list can serve for both types of allocations. The discussion of the RFC for this and Mel's measurements indicate that there may not be too much of a point left to having separate lists for hot and cold pages (see http://marc.info/?t=119492914200001&r=1&w=2). Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Martin Bligh <mbligh@mbligh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
d773ed6b |
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17-Oct-2007 |
David Rientjes <rientjes@google.com> |
mm: test and set zone reclaim lock before starting reclaim Introduces new zone flag interface for testing and setting flags: int zone_test_and_set_flag(struct zone *zone, zone_flags_t flag) Instead of setting and clearing ZONE_RECLAIM_LOCKED each time shrink_zone() is called, this flag is test and set before starting zone reclaim. Zone reclaim starts in __alloc_pages() when a zone's watermark fails and the system is in zone_reclaim_mode. If it's already in reclaim, there's no need to start again so it is simply considered full for that allocation attempt. There is a change of behavior with regard to concurrent zone shrinking. It is now possible for try_to_free_pages() or kswapd to already be shrinking a particular zone when __alloc_pages() starts zone reclaim. In this case, it is possible for two concurrent threads to invoke shrink_zone() for a single zone. This change forbids a zone to be in zone reclaim twice, which was always the behavior, but allows for concurrent try_to_free_pages() or kswapd shrinking when starting zone reclaim. Cc: Andrea Arcangeli <andrea@suse.de> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
098d7f12 |
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17-Oct-2007 |
David Rientjes <rientjes@google.com> |
oom: add per-zone locking OOM killer synchronization should be done with zone granularity so that memory policy and cpuset allocations may have their corresponding zones locked and allow parallel kills for other OOM conditions that may exist elsewhere in the system. DMA allocations can be targeted at the zone level, which would not be possible if locking was done in nodes or globally. Synchronization shall be done with a variation of "trylocks." The goal is to put the current task to sleep and restart the failed allocation attempt later if the trylock fails. Otherwise, the OOM killer is invoked. Each zone in the zonelist that __alloc_pages() was called with is checked for the newly-introduced ZONE_OOM_LOCKED flag. If any zone has this flag present, the "trylock" to serialize the OOM killer fails and returns zero. Otherwise, all the zones have ZONE_OOM_LOCKED set and the try_set_zone_oom() function returns non-zero. Cc: Andrea Arcangeli <andrea@suse.de> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e815af95 |
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17-Oct-2007 |
David Rientjes <rientjes@google.com> |
oom: change all_unreclaimable zone member to flags Convert the int all_unreclaimable member of struct zone to unsigned long flags. This can now be used to specify several different zone flags such as all_unreclaimable and reclaim_in_progress, which can now be removed and converted to a per-zone flag. Flags are set and cleared as follows: zone_set_flag(struct zone *zone, zone_flags_t flag) zone_clear_flag(struct zone *zone, zone_flags_t flag) Defines the first zone flags, ZONE_ALL_UNRECLAIMABLE and ZONE_RECLAIM_LOCKED, which have the same semantics as the old zone->all_unreclaimable and zone->reclaim_in_progress, respectively. Also converts all current users that set or clear either flag to use the new interface. Helper functions are defined to test the flags: int zone_is_all_unreclaimable(const struct zone *zone) int zone_is_reclaim_locked(const struct zone *zone) All flag operators are of the atomic variety because there are currently readers that are implemented that do not take zone->lock. [akpm@linux-foundation.org: add needed include] Cc: Andrea Arcangeli <andrea@suse.de> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a5d76b54 |
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16-Oct-2007 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
memory unplug: page isolation Implement generic chunk-of-pages isolation method by using page grouping ops. This patch add MIGRATE_ISOLATE to MIGRATE_TYPES. By this - MIGRATE_TYPES increases. - bitmap for migratetype is enlarged. pages of MIGRATE_ISOLATE migratetype will not be allocated even if it is free. By this, you can isolated *freed* pages from users. How-to-free pages is not a purpose of this patch. You may use reclaim and migrate codes to free pages. If start_isolate_page_range(start,end) is called, - migratetype of the range turns to be MIGRATE_ISOLATE if its type is MIGRATE_MOVABLE. (*) this check can be updated if other memory reclaiming works make progress. - MIGRATE_ISOLATE is not on migratetype fallback list. - All free pages and will-be-freed pages are isolated. To check all pages in the range are isolated or not, use test_pages_isolated(), To cancel isolation, use undo_isolate_page_range(). Changes V6 -> V7 - removed unnecessary #ifdef There are HOLES_IN_ZONE handling codes...I'm glad if we can remove them.. Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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467c996c |
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16-Oct-2007 |
Mel Gorman <mel@csn.ul.ie> |
Print out statistics in relation to fragmentation avoidance to /proc/pagetypeinfo This patch provides fragmentation avoidance statistics via /proc/pagetypeinfo. The information is collected only on request so there is no runtime overhead. The statistics are in three parts: The first part prints information on the size of blocks that pages are being grouped on and looks like Page block order: 10 Pages per block: 1024 The second part is a more detailed version of /proc/buddyinfo and looks like Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10 Node 0, zone DMA, type Unmovable 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type Reclaimable 1 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type Movable 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type Reserve 0 4 4 0 0 0 0 1 0 1 0 Node 0, zone Normal, type Unmovable 111 8 4 4 2 3 1 0 0 0 0 Node 0, zone Normal, type Reclaimable 293 89 8 0 0 0 0 0 0 0 0 Node 0, zone Normal, type Movable 1 6 13 9 7 6 3 0 0 0 0 Node 0, zone Normal, type Reserve 0 0 0 0 0 0 0 0 0 0 4 The third part looks like Number of blocks type Unmovable Reclaimable Movable Reserve Node 0, zone DMA 0 1 2 1 Node 0, zone Normal 3 17 94 4 To walk the zones within a node with interrupts disabled, walk_zones_in_node() is introduced and shared between /proc/buddyinfo, /proc/zoneinfo and /proc/pagetypeinfo to reduce code duplication. It seems specific to what vmstat.c requires but could be broken out as a general utility function in mmzone.c if there were other other potential users. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d9c23400 |
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16-Oct-2007 |
Mel Gorman <mel@csn.ul.ie> |
Do not depend on MAX_ORDER when grouping pages by mobility Currently mobility grouping works at the MAX_ORDER_NR_PAGES level. This makes sense for the majority of users where this is also the huge page size. However, on platforms like ia64 where the huge page size is runtime configurable it is desirable to group at a lower order. On x86_64 and occasionally on x86, the hugepage size may not always be MAX_ORDER_NR_PAGES. This patch groups pages together based on the value of HUGETLB_PAGE_ORDER. It uses a compile-time constant if possible and a variable where the huge page size is runtime configurable. It is assumed that grouping should be done at the lowest sensible order and that the user would not want to override this. If this is not true, page_block order could be forced to a variable initialised via a boot-time kernel parameter. One potential issue with this patch is that IA64 now parses hugepagesz with early_param() instead of __setup(). __setup() is called after the memory allocator has been initialised and the pageblock bitmaps already setup. In tests on one IA64 there did not seem to be any problem with using early_param() and in fact may be more correct as it guarantees the parameter is handled before the parsing of hugepages=. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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64c5e135 |
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16-Oct-2007 |
Mel Gorman <mel@csn.ul.ie> |
don't group high order atomic allocations Grouping high-order atomic allocations together was intended to allow bursty users of atomic allocations to work such as e1000 in situations where their preallocated buffers were depleted. This did not work in at least one case with a wireless network adapter needing order-1 allocations frequently. To resolve that, the free pages used for min_free_kbytes were moved to separate contiguous blocks with the patch bias-the-location-of-pages-freed-for-min_free_kbytes-in-the-same-max_order_nr_pages-blocks. It is felt that keeping the free pages in the same contiguous blocks should be sufficient for bursty short-lived high-order atomic allocations to succeed, maybe even with the e1000. Even if there is a failure, increasing the value of min_free_kbytes will free pages as contiguous bloks in contrast to the standard buddy allocator which makes no attempt to keep the minimum number of free pages contiguous. This patch backs out grouping high order atomic allocations together to determine if it is really needed or not. If a new report comes in about high-order atomic allocations failing, the feature can be reintroduced to determine if it fixes the problem or not. As a side-effect, this patch reduces by 1 the number of bits required to track the mobility type of pages within a MAX_ORDER_NR_PAGES block. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ac0e5b7a |
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16-Oct-2007 |
Mel Gorman <mel@csn.ul.ie> |
remove PAGE_GROUP_BY_MOBILITY Grouping pages by mobility can be disabled at compile-time. This was considered undesirable by a number of people. However, in the current stack of patches, it is not a simple case of just dropping the configurable patch as it would cause merge conflicts. This patch backs out the configuration option. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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56fd56b8 |
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16-Oct-2007 |
Mel Gorman <mel@csn.ul.ie> |
Bias the location of pages freed for min_free_kbytes in the same MAX_ORDER_NR_PAGES blocks The standard buddy allocator always favours the smallest block of pages. The effect of this is that the pages free to satisfy min_free_kbytes tends to be preserved since boot time at the same location of memory ffor a very long time and as a contiguous block. When an administrator sets the reserve at 16384 at boot time, it tends to be the same MAX_ORDER blocks that remain free. This allows the occasional high atomic allocation to succeed up until the point the blocks are split. In practice, it is difficult to split these blocks but when they do split, the benefit of having min_free_kbytes for contiguous blocks disappears. Additionally, increasing min_free_kbytes once the system has been running for some time has no guarantee of creating contiguous blocks. On the other hand, CONFIG_PAGE_GROUP_BY_MOBILITY favours splitting large blocks when there are no free pages of the appropriate type available. A side-effect of this is that all blocks in memory tends to be used up and the contiguous free blocks from boot time are not preserved like in the vanilla allocator. This can cause a problem if a new caller is unwilling to reclaim or does not reclaim for long enough. A failure scenario was found for a wireless network device allocating order-1 atomic allocations but the allocations were not intense or frequent enough for a whole block of pages to be preserved for MIGRATE_HIGHALLOC. This was reproduced on a desktop by booting with mem=256mb, forcing the driver to allocate at order-1, running a bittorrent client (downloading a debian ISO) and building a kernel with -j2. This patch addresses the problem on the desktop machine booted with mem=256mb. It works by setting aside a reserve of MAX_ORDER_NR_PAGES blocks, the number of which depends on the value of min_free_kbytes. These blocks are only fallen back to when there is no other free pages. Then the smallest possible page is used just like the normal buddy allocator instead of the largest possible page to preserve contiguous pages The pages in free lists in the reserve blocks are never taken for another migrate type. The results is that even if min_free_kbytes is set to a low value, contiguous blocks will be preserved in the MIGRATE_RESERVE blocks. This works better than the vanilla allocator because if min_free_kbytes is increased, a new reserve block will be chosen based on the location of reclaimable pages and the block will free up as contiguous pages. In the vanilla allocator, no effort is made to target a block of pages to free as contiguous pages and min_free_kbytes pages are scattered randomly. This effect has been observed on the test machine. min_free_kbytes was set initially low but it was kept as a contiguous free block within MIGRATE_RESERVE. min_free_kbytes was then set to a higher value and over a period of time, the free blocks were within the reserve and coalescing. How long it takes to free up depends on how quickly LRU is rotating. Amusingly, this means that more activity will free the blocks faster. This mechanism potentially replaces MIGRATE_HIGHALLOC as it may be more effective than grouping contiguous free pages together. It all depends on whether the number of active atomic high allocations exceeds min_free_kbytes or not. If the number of active allocations exceeds min_free_kbytes, it's worth it but maybe in that situation, min_free_kbytes should be set higher. Once there are no more reports of allocation failures, a patch will be submitted that backs out MIGRATE_HIGHALLOC and see if the reports stay missing. Credit to Mariusz Kozlowski for discovering the problem, describing the failure scenario and testing patches and scenarios. [akpm@linux-foundation.org: cleanups] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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5c0e3066 |
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16-Oct-2007 |
Mel Gorman <mel@csn.ul.ie> |
Fix corruption of memmap on IA64 SPARSEMEM when mem_section is not a power of 2 There are problems in the use of SPARSEMEM and pageblock flags that causes problems on ia64. The first part of the problem is that units are incorrect in SECTION_BLOCKFLAGS_BITS computation. This results in a map_section's section_mem_map being treated as part of a bitmap which isn't good. This was evident with an invalid virtual address when mem_init attempted to free bootmem pages while relinquishing control from the bootmem allocator. The second part of the problem occurs because the pageblock flags bitmap is be located with the mem_section. The SECTIONS_PER_ROOT computation using sizeof (mem_section) may not be a power of 2 depending on the size of the bitmap. This renders masks and other such things not power of 2 base. This issue was seen with SPARSEMEM_EXTREME on ia64. This patch moves the bitmap outside of mem_section and uses a pointer instead in the mem_section. The bitmaps are allocated when the section is being initialised. Note that sparse_early_usemap_alloc() does not use alloc_remap() like sparse_early_mem_map_alloc(). The allocation required for the bitmap on x86, the only architecture that uses alloc_remap is typically smaller than a cache line. alloc_remap() pads out allocations to the cache size which would be a needless waste. Credit to Bob Picco for identifying the original problem and effecting a fix for the SECTION_BLOCKFLAGS_BITS calculation. Credit to Andy Whitcroft for devising the best way of allocating the bitmaps only when required for the section. [wli@holomorphy.com: warning fix] Signed-off-by: Bob Picco <bob.picco@hp.com> Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: William Irwin <bill.irwin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e010487d |
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16-Oct-2007 |
Mel Gorman <mel@csn.ul.ie> |
Group high-order atomic allocations In rare cases, the kernel needs to allocate a high-order block of pages without sleeping. For example, this is the case with e1000 cards configured to use jumbo frames. Migrating or reclaiming pages in this situation is not an option. This patch groups these allocations together as much as possible by adding a new MIGRATE_TYPE. The MIGRATE_HIGHATOMIC type are exactly what they sound like. Care is taken that pages of other migrate types do not use the same blocks as high-order atomic allocations. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e12ba74d |
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16-Oct-2007 |
Mel Gorman <mel@csn.ul.ie> |
Group short-lived and reclaimable kernel allocations This patch marks a number of allocations that are either short-lived such as network buffers or are reclaimable such as inode allocations. When something like updatedb is called, long-lived and unmovable kernel allocations tend to be spread throughout the address space which increases fragmentation. This patch groups these allocations together as much as possible by adding a new MIGRATE_TYPE. The MIGRATE_RECLAIMABLE type is for allocations that can be reclaimed on demand, but not moved. i.e. they can be migrated by deleting them and re-reading the information from elsewhere. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b92a6edd |
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16-Oct-2007 |
Mel Gorman <mel@csn.ul.ie> |
Add a configure option to group pages by mobility The grouping mechanism has some memory overhead and a more complex allocation path. This patch allows the strategy to be disabled for small memory systems or if it is known the workload is suffering because of the strategy. It also acts to show where the page groupings strategy interacts with the standard buddy allocator. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Joel Schopp <jschopp@austin.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b2a0ac88 |
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16-Oct-2007 |
Mel Gorman <mel@csn.ul.ie> |
Split the free lists for movable and unmovable allocations This patch adds the core of the fragmentation reduction strategy. It works by grouping pages together based on their ability to migrate or be reclaimed. Basically, it works by breaking the list in zone->free_area list into MIGRATE_TYPES number of lists. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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835c134e |
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16-Oct-2007 |
Mel Gorman <mel@csn.ul.ie> |
Add a bitmap that is used to track flags affecting a block of pages Here is the latest revision of the anti-fragmentation patches. Of particular note in this version is special treatment of high-order atomic allocations. Care is taken to group them together and avoid grouping pages of other types near them. Artifical tests imply that it works. I'm trying to get the hardware together that would allow setting up of a "real" test. If anyone already has a setup and test that can trigger the atomic-allocation problem, I'd appreciate a test of these patches and a report. The second major change is that these patches will apply cleanly with patches that implement anti-fragmentation through zones. kernbench shows effectively no performance difference varying between -0.2% and +2% on a variety of test machines. Success rates for huge page allocation are dramatically increased. For example, on a ppc64 machine, the vanilla kernel was only able to allocate 1% of memory as a hugepage and this was due to a single hugepage reserved as min_free_kbytes. With these patches applied, 17% was allocatable as superpages. With reclaim-related fixes from Andy Whitcroft, it was 40% and further reclaim-related improvements should increase this further. Changelog Since V28 o Group high-order atomic allocations together o It is no longer required to set min_free_kbytes to 10% of memory. A value of 16384 in most cases will be sufficient o Now applied with zone-based anti-fragmentation o Fix incorrect VM_BUG_ON within buffered_rmqueue() o Reorder the stack so later patches do not back out work from earlier patches o Fix bug were journal pages were being treated as movable o Bias placement of non-movable pages to lower PFNs o More agressive clustering of reclaimable pages in reactions to workloads like updatedb that flood the size of inode caches Changelog Since V27 o Renamed anti-fragmentation to Page Clustering. Anti-fragmentation was giving the mistaken impression that it was the 100% solution for high order allocations. Instead, it greatly increases the chances high-order allocations will succeed and lays the foundation for defragmentation and memory hot-remove to work properly o Redefine page groupings based on ability to migrate or reclaim instead of basing on reclaimability alone o Get rid of spurious inits o Per-cpu lists are no longer split up per-type. Instead the per-cpu list is searched for a page of the appropriate type o Added more explanation commentary o Fix up bug in pageblock code where bitmap was used before being initalised Changelog Since V26 o Fix double init of lists in setup_pageset Changelog Since V25 o Fix loop order of for_each_rclmtype_order so that order of loop matches args o gfpflags_to_rclmtype uses gfp_t instead of unsigned long o Rename get_pageblock_type() to get_page_rclmtype() o Fix alignment problem in move_freepages() o Add mechanism for assigning flags to blocks of pages instead of page->flags o On fallback, do not examine the preferred list of free pages a second time The purpose of these patches is to reduce external fragmentation by grouping pages of related types together. When pages are migrated (or reclaimed under memory pressure), large contiguous pages will be freed. This patch works by categorising allocations by their ability to migrate; Movable - The pages may be moved with the page migration mechanism. These are generally userspace pages. Reclaimable - These are allocations for some kernel caches that are reclaimable or allocations that are known to be very short-lived. Unmovable - These are pages that are allocated by the kernel that are not trivially reclaimed. For example, the memory allocated for a loaded module would be in this category. By default, allocations are considered to be of this type HighAtomic - These are high-order allocations belonging to callers that cannot sleep or perform any IO. In practice, this is restricted to jumbo frame allocation for network receive. It is assumed that the allocations are short-lived Instead of having one MAX_ORDER-sized array of free lists in struct free_area, there is one for each type of reclaimability. Once a 2^MAX_ORDER block of pages is split for a type of allocation, it is added to the free-lists for that type, in effect reserving it. Hence, over time, pages of the different types can be clustered together. When the preferred freelists are expired, the largest possible block is taken from an alternative list. Buddies that are split from that large block are placed on the preferred allocation-type freelists to mitigate fragmentation. This implementation gives best-effort for low fragmentation in all zones. Ideally, min_free_kbytes needs to be set to a value equal to 4 * (1 << (MAX_ORDER-1)) pages in most cases. This would be 16384 on x86 and x86_64 for example. Our tests show that about 60-70% of physical memory can be allocated on a desktop after a few days uptime. In benchmarks and stress tests, we are finding that 80% of memory is available as contiguous blocks at the end of the test. To compare, a standard kernel was getting < 1% of memory as large pages on a desktop and about 8-12% of memory as large pages at the end of stress tests. Following this email are 12 patches that implement thie page grouping feature. The first patch introduces a mechanism for storing flags related to a whole block of pages. Then allocations are split between movable and all other allocations. Following that are patches to deal with per-cpu pages and make the mechanism configurable. The next patch moves free pages between lists when partially allocated blocks are used for pages of another migrate type. The second last patch groups reclaimable kernel allocations such as inode caches together. The final patch related to groupings keeps high-order atomic allocations. The last two patches are more concerned with control of fragmentation. The second last patch biases placement of non-movable allocations towards the start of memory. This is with a view of supporting memory hot-remove of DIMMs with higher PFNs in the future. The biasing could be enforced a lot heavier but it would cost. The last patch agressively clusters reclaimable pages like inode caches together. The fragmentation reduction strategy needs to track if pages within a block can be moved or reclaimed so that pages are freed to the appropriate list. This patch adds a bitmap for flags affecting a whole a MAX_ORDER block of pages. In non-SPARSEMEM configurations, the bitmap is stored in the struct zone and allocated during initialisation. SPARSEMEM statically allocates the bitmap in a struct mem_section so that bitmaps do not have to be resized during memory hotadd. This wastes a small amount of memory per unused section (usually sizeof(unsigned long)) but the complexity of dynamically allocating the memory is quite high. Additional credit to Andy Whitcroft who reviewed up an earlier implementation of the mechanism an suggested how to make it a *lot* cleaner. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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523b9458 |
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16-Oct-2007 |
Christoph Lameter <clameter@sgi.com> |
Memoryless nodes: Fix GFP_THISNODE behavior GFP_THISNODE checks that the zone selected is within the pgdat (node) of the first zone of a nodelist. That only works if the node has memory. A memoryless node will have its first node on another pgdat (node). GFP_THISNODE currently will return simply memory on the first pgdat. Thus it is returning memory on other nodes. GFP_THISNODE should fail if there is no local memory on a node. Add a new set of zonelists for each node that only contain the nodes that belong to the zones itself so that no fallback is possible. Then modify gfp_type to pickup the right zone based on the presence of __GFP_THISNODE. Drop the existing GFP_THISNODE checks from the page_allocators hot path. Signed-off-by: Christoph Lameter <clameter@sgi.com> Acked-by: Nishanth Aravamudan <nacc@us.ibm.com> Tested-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Acked-by: Bob Picco <bob.picco@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@skynet.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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540557b9 |
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16-Oct-2007 |
Andy Whitcroft <apw@shadowen.org> |
sparsemem: record when a section has a valid mem_map We have flags to indicate whether a section actually has a valid mem_map associated with it. This is never set and we rely solely on the present bit to indicate a section is valid. By definition a section is not valid if it has no mem_map and there is a window during init where the present bit is set but there is no mem_map, during which pfn_valid() will return true incorrectly. Use the existing SECTION_HAS_MEM_MAP flag to indicate the presence of a valid mem_map. Switch valid_section{,_nr} and pfn_valid() to this bit. Add a new present_section{,_nr} and pfn_present() interfaces for those users who care to know that a section is going to be valid. [akpm@linux-foundation.org: coding-syle fixes] Signed-off-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <clameter@sgi.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: "David S. Miller" <davem@davemloft.net> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b377fd39 |
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22-Aug-2007 |
Mel Gorman <mel@csn.ul.ie> |
Apply memory policies to top two highest zones when highest zone is ZONE_MOVABLE The NUMA layer only supports NUMA policies for the highest zone. When ZONE_MOVABLE is configured with kernelcore=, the the highest zone becomes ZONE_MOVABLE. The result is that policies are only applied to allocations like anonymous pages and page cache allocated from ZONE_MOVABLE when the zone is used. This patch applies policies to the two highest zones when the highest zone is ZONE_MOVABLE. As ZONE_MOVABLE consists of pages from the highest "real" zone, it's always functionally equivalent. The patch has been tested on a variety of machines both NUMA and non-NUMA covering x86, x86_64 and ppc64. No abnormal results were seen in kernbench, tbench, dbench or hackbench. It passes regression tests from the numactl package with and without kernelcore= once numactl tests are patched to wait for vmstat counters to update. akpm: this is the nasty hack to fix NUMA mempolicies in the presence of ZONE_MOVABLE and kernelcore= in 2.6.23. Christoph says "For .24 either merge the mobility or get the other solution that Mel is working on. That solution would only use a single zonelist per node and filter on the fly. That may help performance and also help to make memory policies work better." Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Tested-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Acked-by: Christoph Lameter <clameter@sgi.com> Cc: Andi Kleen <ak@suse.de> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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99eb8a55 |
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31-Jul-2007 |
Adrian Bunk <bunk@stusta.de> |
Remove the arm26 port The arm26 port has been in a state where it was far from even compiling for quite some time. Ian Molton agreed with the removal. Signed-off-by: Adrian Bunk <bunk@stusta.de> Cc: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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5ad333eb |
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17-Jul-2007 |
Andy Whitcroft <apw@shadowen.org> |
Lumpy Reclaim V4 When we are out of memory of a suitable size we enter reclaim. The current reclaim algorithm targets pages in LRU order, which is great for fairness at order-0 but highly unsuitable if you desire pages at higher orders. To get pages of higher order we must shoot down a very high proportion of memory; >95% in a lot of cases. This patch set adds a lumpy reclaim algorithm to the allocator. It targets groups of pages at the specified order anchored at the end of the active and inactive lists. This encourages groups of pages at the requested orders to move from active to inactive, and active to free lists. This behaviour is only triggered out of direct reclaim when higher order pages have been requested. This patch set is particularly effective when utilised with an anti-fragmentation scheme which groups pages of similar reclaimability together. This patch set is based on Peter Zijlstra's lumpy reclaim V2 patch which forms the foundation. Credit to Mel Gorman for sanitity checking. Mel said: The patches have an application with hugepage pool resizing. When lumpy-reclaim is used used with ZONE_MOVABLE, the hugepages pool can be resized with greater reliability. Testing on a desktop machine with 2GB of RAM showed that growing the hugepage pool with ZONE_MOVABLE on it's own was very slow as the success rate was quite low. Without lumpy-reclaim, each attempt to grow the pool by 100 pages would yield 1 or 2 hugepages. With lumpy-reclaim, getting 40 to 70 hugepages on each attempt was typical. [akpm@osdl.org: ia64 pfn_to_nid fixes and loop cleanup] [bunk@stusta.de: static declarations for internal functions] [a.p.zijlstra@chello.nl: initial lumpy V2 implementation] Signed-off-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Bob Picco <bob.picco@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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2a1e274a |
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17-Jul-2007 |
Mel Gorman <mel@csn.ul.ie> |
Create the ZONE_MOVABLE zone The following 8 patches against 2.6.20-mm2 create a zone called ZONE_MOVABLE that is only usable by allocations that specify both __GFP_HIGHMEM and __GFP_MOVABLE. This has the effect of keeping all non-movable pages within a single memory partition while allowing movable allocations to be satisfied from either partition. The patches may be applied with the list-based anti-fragmentation patches that groups pages together based on mobility. The size of the zone is determined by a kernelcore= parameter specified at boot-time. This specifies how much memory is usable by non-movable allocations and the remainder is used for ZONE_MOVABLE. Any range of pages within ZONE_MOVABLE can be released by migrating the pages or by reclaiming. When selecting a zone to take pages from for ZONE_MOVABLE, there are two things to consider. First, only memory from the highest populated zone is used for ZONE_MOVABLE. On the x86, this is probably going to be ZONE_HIGHMEM but it would be ZONE_DMA on ppc64 or possibly ZONE_DMA32 on x86_64. Second, the amount of memory usable by the kernel will be spread evenly throughout NUMA nodes where possible. If the nodes are not of equal size, the amount of memory usable by the kernel on some nodes may be greater than others. By default, the zone is not as useful for hugetlb allocations because they are pinned and non-migratable (currently at least). A sysctl is provided that allows huge pages to be allocated from that zone. This means that the huge page pool can be resized to the size of ZONE_MOVABLE during the lifetime of the system assuming that pages are not mlocked. Despite huge pages being non-movable, we do not introduce additional external fragmentation of note as huge pages are always the largest contiguous block we care about. Credit goes to Andy Whitcroft for catching a large variety of problems during review of the patches. This patch creates an additional zone, ZONE_MOVABLE. This zone is only usable by allocations which specify both __GFP_HIGHMEM and __GFP_MOVABLE. Hot-added memory continues to be placed in their existing destination as there is no mechanism to redirect them to a specific zone. [y-goto@jp.fujitsu.com: Fix section mismatch of memory hotplug related code] [akpm@linux-foundation.org: various fixes] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f0c0b2b8 |
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16-Jul-2007 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
change zonelist order: zonelist order selection logic Make zonelist creation policy selectable from sysctl/boot option v6. This patch makes NUMA's zonelist (of pgdat) order selectable. Available order are Default(automatic)/ Node-based / Zone-based. [Default Order] The kernel selects Node-based or Zone-based order automatically. [Node-based Order] This policy treats the locality of memory as the most important parameter. Zonelist order is created by each zone's locality. This means lower zones (ex. ZONE_DMA) can be used before higher zone (ex. ZONE_NORMAL) exhausion. IOW. ZONE_DMA will be in the middle of zonelist. current 2.6.21 kernel uses this. Pros. * A user can expect local memory as much as possible. Cons. * lower zone will be exhansted before higher zone. This may cause OOM_KILL. Maybe suitable if ZONE_DMA is relatively big and you never see OOM_KILL because of ZONE_DMA exhaution and you need the best locality. (example) assume 2 node NUMA. node(0) has ZONE_DMA/ZONE_NORMAL, node(1) has ZONE_NORMAL. *node(0)'s memory allocation order: node(0)'s NORMAL -> node(0)'s DMA -> node(1)'s NORMAL. *node(1)'s memory allocation order: node(1)'s NORMAL -> node(0)'s NORMAL -> node(0)'s DMA. [Zone-based order] This policy treats the zone type as the most important parameter. Zonelist order is created by zone-type order. This means lower zone never be used bofere higher zone exhaustion. IOW. ZONE_DMA will be always at the tail of zonelist. Pros. * OOM_KILL(bacause of lower zone) occurs only if the whole zones are exhausted. Cons. * memory locality may not be best. (example) assume 2 node NUMA. node(0) has ZONE_DMA/ZONE_NORMAL, node(1) has ZONE_NORMAL. *node(0)'s memory allocation order: node(0)'s NORMAL -> node(1)'s NORMAL -> node(0)'s DMA. *node(1)'s memory allocation order: node(1)'s NORMAL -> node(0)'s NORMAL -> node(0)'s DMA. bootoption "numa_zonelist_order=" and proc/sysctl is supporetd. command: %echo N > /proc/sys/vm/numa_zonelist_order Will rebuild zonelist in Node-based order. command: %echo Z > /proc/sys/vm/numa_zonelist_order Will rebuild zonelist in Zone-based order. Thanks to Lee Schermerhorn, he gives me much help and codes. [Lee.Schermerhorn@hp.com: add check_highest_zone to build_zonelists_in_zone_order] [akpm@linux-foundation.org: build fix] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: Andi Kleen <ak@suse.de> Cc: "jesse.barnes@intel.com" <jesse.barnes@intel.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4037d452 |
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09-May-2007 |
Christoph Lameter <clameter@sgi.com> |
Move remote node draining out of slab allocators Currently the slab allocators contain callbacks into the page allocator to perform the draining of pagesets on remote nodes. This requires SLUB to have a whole subsystem in order to be compatible with SLAB. Moving node draining out of the slab allocators avoids a section of code in SLUB. Move the node draining so that is is done when the vm statistics are updated. At that point we are already touching all the cachelines with the pagesets of a processor. Add a expire counter there. If we have to update per zone or global vm statistics then assume that the pageset will require subsequent draining. The expire counter will be decremented on each vm stats update pass until it reaches zero. Then we will drain one batch from the pageset. The draining will cause vm counter updates which will then cause another expiration until the pcp is empty. So we will drain a batch every 3 seconds. Note that remote node draining is a somewhat esoteric feature that is required on large NUMA systems because otherwise significant portions of system memory can become trapped in pcp queues. The number of pcp is determined by the number of processors and nodes in a system. A system with 4 processors and 2 nodes has 8 pcps which is okay. But a system with 1024 processors and 512 nodes has 512k pcps with a high potential for large amount of memory being caught in them. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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14e07298 |
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06-May-2007 |
Andy Whitcroft <apw@shadowen.org> |
add pfn_valid_within helper for sub-MAX_ORDER hole detection Generally we work under the assumption that memory the mem_map array is contigious and valid out to MAX_ORDER_NR_PAGES block of pages, ie. that if we have validated any page within this MAX_ORDER_NR_PAGES block we need not check any other. This is not true when CONFIG_HOLES_IN_ZONE is set and we must check each and every reference we make from a pfn. Add a pfn_valid_within() helper which should be used when scanning pages within a MAX_ORDER_NR_PAGES block when we have already checked the validility of the block normally with pfn_valid(). This can then be optimised away when we do not have holes within a MAX_ORDER_NR_PAGES block of pages. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Bob Picco <bob.picco@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4b51d669 |
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10-Feb-2007 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] optional ZONE_DMA: optional ZONE_DMA in the VM Make ZONE_DMA optional in core code. - ifdef all code for ZONE_DMA and related definitions following the example for ZONE_DMA32 and ZONE_HIGHMEM. - Without ZONE_DMA, ZONE_HIGHMEM and ZONE_DMA32 we get to a ZONES_SHIFT of 0. - Modify the VM statistics to work correctly without a DMA zone. - Modify slab to not create DMA slabs if there is no ZONE_DMA. [akpm@osdl.org: cleanup] [jdike@addtoit.com: build fix] [apw@shadowen.org: Simplify calculation of the number of bits we need for ZONES_SHIFT] Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Matthew Wilcox <willy@debian.org> Cc: James Bottomley <James.Bottomley@steeleye.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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05a0416b |
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10-Feb-2007 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] Drop __get_zone_counts() Values are readily available via ZVC per node and global sums. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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51ed4491 |
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10-Feb-2007 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] Reorder ZVCs according to cacheline The global and per zone counter sums are in arrays of longs. Reorder the ZVCs so that the most frequently used ZVCs are put into the same cacheline. That way calculations of the global, node and per zone vm state touches only a single cacheline. This is mostly important for 64 bit systems were one 128 byte cacheline takes only 8 longs. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d23ad423 |
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10-Feb-2007 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] Use ZVC for free_pages This is again simplifies some of the VM counter calculations through the use of the ZVC consolidated counters. [michal.k.k.piotrowski@gmail.com: build fix] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Michal Piotrowski <michal.k.k.piotrowski@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c8785385 |
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10-Feb-2007 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] Use ZVC for inactive and active counts The determination of the dirty ratio to determine writeback behavior is currently based on the number of total pages on the system. However, not all pages in the system may be dirtied. Thus the ratio is always too low and can never reach 100%. The ratio may be particularly skewed if large hugepage allocations, slab allocations or device driver buffers make large sections of memory not available anymore. In that case we may get into a situation in which f.e. the background writeback ratio of 40% cannot be reached anymore which leads to undesired writeback behavior. This patchset fixes that issue by determining the ratio based on the actual pages that may potentially be dirty. These are the pages on the active and the inactive list plus free pages. The problem with those counts has so far been that it is expensive to calculate these because counts from multiple nodes and multiple zones will have to be summed up. This patchset makes these counters ZVC counters. This means that a current sum per zone, per node and for the whole system is always available via global variables and not expensive anymore to calculate. The patchset results in some other good side effects: - Removal of the various functions that sum up free, active and inactive page counts - Cleanup of the functions that display information via the proc filesystem. This patch: The use of a ZVC for nr_inactive and nr_active allows a simplification of some counter operations. More ZVC functionality is used for sums etc in the following patches. [akpm@osdl.org: UP build fix] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a2f3aa02 |
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11-Jan-2007 |
Dave Hansen <haveblue@us.ibm.com> |
[PATCH] Fix sparsemem on Cell Fix an oops experienced on the Cell architecture when init-time functions, early_*(), are called at runtime. It alters the call paths to make sure that the callers explicitly say whether the call is being made on behalf of a hotplug even, or happening at boot-time. It has been compile tested on ppc64, ia64, s390, i386 and x86_64. Acked-by: Arnd Bergmann <arndb@de.ibm.com> Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Acked-by: Andy Whitcroft <apw@shadowen.org> Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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15ad7cdc |
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06-Dec-2006 |
Helge Deller <deller@gmx.de> |
[PATCH] struct seq_operations and struct file_operations constification - move some file_operations structs into the .rodata section - move static strings from policy_types[] array into the .rodata section - fix generic seq_operations usages, so that those structs may be defined as "const" as well [akpm@osdl.org: couple of fixes] Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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7253f4ef |
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06-Dec-2006 |
Paul Jackson <pj@sgi.com> |
[PATCH] memory page_alloc zonelist caching reorder structure Rearrange the struct members in the 'struct zonelist_cache' structure, so as to put the readonly (once initialized) z_to_n[] array first, where it will come right after the zones[] array in struct zonelist. This pretty much eliminates the chance that the two frequently written elements of 'struct zonelist_cache', the fullzones bitmap and last_full_zap times, will end up on the same cache line as the performance sensitive, frequently read, never (after init) written zones[] array. Keeping frequently written data off frequently read cache lines is good for performance. Thanks to Rohit Seth for the suggestion. Signed-off-by: Paul Jackson <pj@sgi.com> Cc: Rohit Seth <rohitseth@google.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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9276b1bc |
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06-Dec-2006 |
Paul Jackson <pj@sgi.com> |
[PATCH] memory page_alloc zonelist caching speedup Optimize the critical zonelist scanning for free pages in the kernel memory allocator by caching the zones that were found to be full recently, and skipping them. Remembers the zones in a zonelist that were short of free memory in the last second. And it stashes a zone-to-node table in the zonelist struct, to optimize that conversion (minimize its cache footprint.) Recent changes: This differs in a significant way from a similar patch that I posted a week ago. Now, instead of having a nodemask_t of recently full nodes, I have a bitmask of recently full zones. This solves a problem that last weeks patch had, which on systems with multiple zones per node (such as DMA zone) would take seeing any of these zones full as meaning that all zones on that node were full. Also I changed names - from "zonelist faster" to "zonelist cache", as that seemed to better convey what we're doing here - caching some of the key zonelist state (for faster access.) See below for some performance benchmark results. After all that discussion with David on why I didn't need them, I went and got some ;). I wanted to verify that I had not hurt the normal case of memory allocation noticeably. At least for my one little microbenchmark, I found (1) the normal case wasn't affected, and (2) workloads that forced scanning across multiple nodes for memory improved up to 10% fewer System CPU cycles and lower elapsed clock time ('sys' and 'real'). Good. See details, below. I didn't have the logic in get_page_from_freelist() for various full nodes and zone reclaim failures correct. That should be fixed up now - notice the new goto labels zonelist_scan, this_zone_full, and try_next_zone, in get_page_from_freelist(). There are two reasons I persued this alternative, over some earlier proposals that would have focused on optimizing the fake numa emulation case by caching the last useful zone: 1) Contrary to what I said before, we (SGI, on large ia64 sn2 systems) have seen real customer loads where the cost to scan the zonelist was a problem, due to many nodes being full of memory before we got to a node we could use. Or at least, I think we have. This was related to me by another engineer, based on experiences from some time past. So this is not guaranteed. Most likely, though. The following approach should help such real numa systems just as much as it helps fake numa systems, or any combination thereof. 2) The effort to distinguish fake from real numa, using node_distance, so that we could cache a fake numa node and optimize choosing it over equivalent distance fake nodes, while continuing to properly scan all real nodes in distance order, was going to require a nasty blob of zonelist and node distance munging. The following approach has no new dependency on node distances or zone sorting. See comment in the patch below for a description of what it actually does. Technical details of note (or controversy): - See the use of "zlc_active" and "did_zlc_setup" below, to delay adding any work for this new mechanism until we've looked at the first zone in zonelist. I figured the odds of the first zone having the memory we needed were high enough that we should just look there, first, then get fancy only if we need to keep looking. - Some odd hackery was needed to add items to struct zonelist, while not tripping up the custom zonelists built by the mm/mempolicy.c code for MPOL_BIND. My usual wordy comments below explain this. Search for "MPOL_BIND". - Some per-node data in the struct zonelist is now modified frequently, with no locking. Multiple CPU cores on a node could hit and mangle this data. The theory is that this is just performance hint data, and the memory allocator will work just fine despite any such mangling. The fields at risk are the struct 'zonelist_cache' fields 'fullzones' (a bitmask) and 'last_full_zap' (unsigned long jiffies). It should all be self correcting after at most a one second delay. - This still does a linear scan of the same lengths as before. All I've optimized is making the scan faster, not algorithmically shorter. It is now able to scan a compact array of 'unsigned short' in the case of many full nodes, so one cache line should cover quite a few nodes, rather than each node hitting another one or two new and distinct cache lines. - If both Andi and Nick don't find this too complicated, I will be (pleasantly) flabbergasted. - I removed the comment claiming we only use one cachline's worth of zonelist. We seem, at least in the fake numa case, to have put the lie to that claim. - I pay no attention to the various watermarks and such in this performance hint. A node could be marked full for one watermark, and then skipped over when searching for a page using a different watermark. I think that's actually quite ok, as it will tend to slightly increase the spreading of memory over other nodes, away from a memory stressed node. =============== Performance - some benchmark results and analysis: This benchmark runs a memory hog program that uses multiple threads to touch alot of memory as quickly as it can. Multiple runs were made, touching 12, 38, 64 or 90 GBytes out of the total 96 GBytes on the system, and using 1, 19, 37, or 55 threads (on a 56 CPU system.) System, user and real (elapsed) timings were recorded for each run, shown in units of seconds, in the table below. Two kernels were tested - 2.6.18-mm3 and the same kernel with this zonelist caching patch added. The table also shows the percentage improvement the zonelist caching sys time is over (lower than) the stock *-mm kernel. number 2.6.18-mm3 zonelist-cache delta (< 0 good) percent GBs N ------------ -------------- ---------------- systime mem threads sys user real sys user real sys user real better 12 1 153 24 177 151 24 176 -2 0 -1 1% 12 19 99 22 8 99 22 8 0 0 0 0% 12 37 111 25 6 112 25 6 1 0 0 -0% 12 55 115 25 5 110 23 5 -5 -2 0 4% 38 1 502 74 576 497 73 570 -5 -1 -6 0% 38 19 426 78 48 373 76 39 -53 -2 -9 12% 38 37 544 83 36 547 82 36 3 -1 0 -0% 38 55 501 77 23 511 80 24 10 3 1 -1% 64 1 917 125 1042 890 124 1014 -27 -1 -28 2% 64 19 1118 138 119 965 141 103 -153 3 -16 13% 64 37 1202 151 94 1136 150 81 -66 -1 -13 5% 64 55 1118 141 61 1072 140 58 -46 -1 -3 4% 90 1 1342 177 1519 1275 174 1450 -67 -3 -69 4% 90 19 2392 199 192 2116 189 176 -276 -10 -16 11% 90 37 3313 238 175 2972 225 145 -341 -13 -30 10% 90 55 1948 210 104 1843 213 100 -105 3 -4 5% Notes: 1) This test ran a memory hog program that started a specified number N of threads, and had each thread allocate and touch 1/N'th of the total memory to be used in the test run in a single loop, writing a constant word to memory, one store every 4096 bytes. Watching this test during some earlier trial runs, I would see each of these threads sit down on one CPU and stay there, for the remainder of the pass, a different CPU for each thread. 2) The 'real' column is not comparable to the 'sys' or 'user' columns. The 'real' column is seconds wall clock time elapsed, from beginning to end of that test pass. The 'sys' and 'user' columns are total CPU seconds spent on that test pass. For a 19 thread test run, for example, the sum of 'sys' and 'user' could be up to 19 times the number of 'real' elapsed wall clock seconds. 3) Tests were run on a fresh, single-user boot, to minimize the amount of memory already in use at the start of the test, and to minimize the amount of background activity that might interfere. 4) Tests were done on a 56 CPU, 28 Node system with 96 GBytes of RAM. 5) Notice that the 'real' time gets large for the single thread runs, even though the measured 'sys' and 'user' times are modest. I'm not sure what that means - probably something to do with it being slow for one thread to be accessing memory along ways away. Perhaps the fake numa system, running ostensibly the same workload, would not show this substantial degradation of 'real' time for one thread on many nodes -- lets hope not. 6) The high thread count passes (one thread per CPU - on 55 of 56 CPUs) ran quite efficiently, as one might expect. Each pair of threads needed to allocate and touch the memory on the node the two threads shared, a pleasantly parallizable workload. 7) The intermediate thread count passes, when asking for alot of memory forcing them to go to a few neighboring nodes, improved the most with this zonelist caching patch. Conclusions: * This zonelist cache patch probably makes little difference one way or the other for most workloads on real numa hardware, if those workloads avoid heavy off node allocations. * For memory intensive workloads requiring substantial off-node allocations on real numa hardware, this patch improves both kernel and elapsed timings up to ten per-cent. * For fake numa systems, I'm optimistic, but will have to leave that up to Rohit Seth to actually test (once I get him a 2.6.18 backport.) Signed-off-by: Paul Jackson <pj@sgi.com> Cc: Rohit Seth <rohitseth@google.com> Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: David Rientjes <rientjes@cs.washington.edu> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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3bb1a852 |
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28-Oct-2006 |
Martin Bligh <mbligh@mbligh.org> |
[PATCH] vmscan: Fix temp_priority race The temp_priority field in zone is racy, as we can walk through a reclaim path, and just before we copy it into prev_priority, it can be overwritten (say with DEF_PRIORITY) by another reclaimer. The same bug is contained in both try_to_free_pages and balance_pgdat, but it is fixed slightly differently. In balance_pgdat, we keep a separate priority record per zone in a local array. In try_to_free_pages there is no need to do this, as the priority level is the same for all zones that we reclaim from. Impact of this bug is that temp_priority is copied into prev_priority, and setting this artificially high causes reclaimers to set distress artificially low. They then fail to reclaim mapped pages, when they are, in fact, under severe memory pressure (their priority may be as low as 0). This causes the OOM killer to fire incorrectly. From: Andrew Morton <akpm@osdl.org> __zone_reclaim() isn't modifying zone->prev_priority. But zone->prev_priority is used in the decision whether or not to bring mapped pages onto the inactive list. Hence there's a risk here that __zone_reclaim() will fail because zone->prev_priority ir large (ie: low urgency) and lots of mapped pages end up stuck on the active list. Fix that up by decreasing (ie making more urgent) zone->prev_priority as __zone_reclaim() scans the zone's pages. This bug perhaps explains why ZONE_RECLAIM_PRIORITY was created. It should be possible to remove that now, and to just start out at DEF_PRIORITY? Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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75167957 |
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21-Oct-2006 |
Andy Whitcroft <apw@shadowen.org> |
[PATCH] Reintroduce NODES_SPAN_OTHER_NODES for powerpc Reintroduce NODES_SPAN_OTHER_NODES for powerpc Revert "[PATCH] Remove SPAN_OTHER_NODES config definition" This reverts commit f62859bb6871c5e4a8e591c60befc8caaf54db8c. Revert "[PATCH] mm: remove arch independent NODES_SPAN_OTHER_NODES" This reverts commit a94b3ab7eab4edcc9b2cb474b188f774c331adf7. Also update the comments to indicate that this is still required and where its used. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Mike Kravetz <kravetz@us.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Will Schmidt <will_schmidt@vnet.ibm.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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d5f541ed |
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27-Sep-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] Add node to zone for the NUMA case Add the node in order to optimize zone_to_nid. Signed-off-by: Christoph Lameter <clameter@sgi.com> Acked-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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5b99cd0e |
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27-Sep-2006 |
Heiko Carstens <hca@linux.ibm.com> |
[PATCH] own header file for struct page This moves the definition of struct page from mm.h to its own header file page-struct.h. This is a prereq to fix SetPageUptodate which is broken on s390: #define SetPageUptodate(_page) do { struct page *__page = (_page); if (!test_and_set_bit(PG_uptodate, &__page->flags)) page_test_and_clear_dirty(_page); } while (0) _page gets used twice in this macro which can cause subtle bugs. Using __page for the page_test_and_clear_dirty call doesn't work since it causes yet another problem with the page_test_and_clear_dirty macro as well. In order to avoid all these problems caused by macros it seems to be a good idea to get rid of them and convert them to static inline functions. Because of header file include order it's necessary to have a seperate header file for the struct page definition. Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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e129b5c2 |
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27-Sep-2006 |
Andrew Morton <akpm@osdl.org> |
[PATCH] vm: add per-zone writeout counter The VM is supposed to minimise the number of pages which get written off the LRU (for IO scheduling efficiency, and for high reclaim-success rates). But we don't actually have a clear way of showing how true this is. So add `nr_vmscan_write' to /proc/vmstat and /proc/zoneinfo - the number of pages which have been written by the vm scanner in this zone and globally. Cc: Christoph Lameter <clameter@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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c713216d |
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27-Sep-2006 |
Mel Gorman <mel@csn.ul.ie> |
[PATCH] Introduce mechanism for registering active regions of memory At a basic level, architectures define structures to record where active ranges of page frames are located. Once located, the code to calculate zone sizes and holes in each architecture is very similar. Some of this zone and hole sizing code is difficult to read for no good reason. This set of patches eliminates the similar-looking architecture-specific code. The patches introduce a mechanism where architectures register where the active ranges of page frames are with add_active_range(). When all areas have been discovered, free_area_init_nodes() is called to initialise the pgdat and zones. The zone sizes and holes are then calculated in an architecture independent manner. Patch 1 introduces the mechanism for registering and initialising PFN ranges Patch 2 changes ppc to use the mechanism - 139 arch-specific LOC removed Patch 3 changes x86 to use the mechanism - 136 arch-specific LOC removed Patch 4 changes x86_64 to use the mechanism - 74 arch-specific LOC removed Patch 5 changes ia64 to use the mechanism - 52 arch-specific LOC removed Patch 6 accounts for mem_map as a memory hole as the pages are not reclaimable. It adjusts the watermarks slightly Tony Luck has successfully tested for ia64 on Itanium with tiger_defconfig, gensparse_defconfig and defconfig. Bob Picco has also tested and debugged on IA64. Jack Steiner successfully boot tested on a mammoth SGI IA64-based machine. These were on patches against 2.6.17-rc1 and release 3 of these patches but there have been no ia64-changes since release 3. There are differences in the zone sizes for x86_64 as the arch-specific code for x86_64 accounts the kernel image and the starting mem_maps as memory holes but the architecture-independent code accounts the memory as present. The big benefit of this set of patches is a sizable reduction of architecture-specific code, some of which is very hairy. There should be a greater reduction when other architectures use the same mechanisms for zone and hole sizing but I lack the hardware to test on. Additional credit; Dave Hansen for the initial suggestion and comments on early patches Andy Whitcroft for reviewing early versions and catching numerous errors Tony Luck for testing and debugging on IA64 Bob Picco for fixing bugs related to pfn registration, reviewing a number of patch revisions, providing a number of suggestions on future direction and testing heavily Jack Steiner and Robin Holt for testing on IA64 and clarifying issues related to memory holes Yasunori for testing on IA64 Andi Kleen for reviewing and feeding back about x86_64 Christian Kujau for providing valuable information related to ACPI problems on x86_64 and testing potential fixes This patch: Define the structure to represent an active range of page frames within a node in an architecture independent manner. Architectures are expected to register active ranges of PFNs using add_active_range(nid, start_pfn, end_pfn) and call free_area_init_nodes() passing the PFNs of the end of each zone. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Bob Picco <bob.picco@hp.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Andi Kleen <ak@muc.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Keith Mannthey" <kmannth@gmail.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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0ff38490 |
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26-Sep-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] zone_reclaim: dynamic slab reclaim Currently one can enable slab reclaim by setting an explicit option in /proc/sys/vm/zone_reclaim_mode. Slab reclaim is then used as a final option if the freeing of unmapped file backed pages is not enough to free enough pages to allow a local allocation. However, that means that the slab can grow excessively and that most memory of a node may be used by slabs. We have had a case where a machine with 46GB of memory was using 40-42GB for slab. Zone reclaim was effective in dealing with pagecache pages. However, slab reclaim was only done during global reclaim (which is a bit rare on NUMA systems). This patch implements slab reclaim during zone reclaim. Zone reclaim occurs if there is a danger of an off node allocation. At that point we 1. Shrink the per node page cache if the number of pagecache pages is more than min_unmapped_ratio percent of pages in a zone. 2. Shrink the slab cache if the number of the nodes reclaimable slab pages (patch depends on earlier one that implements that counter) are more than min_slab_ratio (a new /proc/sys/vm tunable). The shrinking of the slab cache is a bit problematic since it is not node specific. So we simply calculate what point in the slab we want to reach (current per node slab use minus the number of pages that neeed to be allocated) and then repeately run the global reclaim until that is unsuccessful or we have reached the limit. I hope we will have zone based slab reclaim at some point which will make that easier. The default for the min_slab_ratio is 5% Also remove the slab option from /proc/sys/vm/zone_reclaim_mode. [akpm@osdl.org: cleanups] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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972d1a7b |
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26-Sep-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] ZVC: Support NR_SLAB_RECLAIMABLE / NR_SLAB_UNRECLAIMABLE Remove the atomic counter for slab_reclaim_pages and replace the counter and NR_SLAB with two ZVC counter that account for unreclaimable and reclaimable slab pages: NR_SLAB_RECLAIMABLE and NR_SLAB_UNRECLAIMABLE. Change the check in vmscan.c to refer to to NR_SLAB_RECLAIMABLE. The intend seems to be to check for slab pages that could be freed. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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8417bba4 |
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26-Sep-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] Replace min_unmapped_ratio by min_unmapped_pages in struct zone *_pages is a better description of the role of the variable. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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19655d34 |
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26-Sep-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] linearly index zone->node_zonelists[] I wonder why we need this bitmask indexing into zone->node_zonelists[]? We always start with the highest zone and then include all lower zones if we build zonelists. Are there really cases where we need allocation from ZONE_DMA or ZONE_HIGHMEM but not ZONE_NORMAL? It seems that the current implementation of highest_zone() makes that already impossible. If we go linear on the index then gfp_zone() == highest_zone() and a lot of definitions fall by the wayside. We can now revert back to the use of gfp_zone() in mempolicy.c ;-) Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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e53ef38d |
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26-Sep-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] reduce MAX_NR_ZONES: make ZONE_HIGHMEM optional Make ZONE_HIGHMEM optional - ifdef out code and definitions related to CONFIG_HIGHMEM - __GFP_HIGHMEM falls back to normal allocations if there is no ZONE_HIGHMEM - GFP_ZONEMASK becomes 0x01 if there is no DMA32 and no HIGHMEM zone. [jdike@addtoit.com: build fix] Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Christoph Lameter <clameter@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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fb0e7942 |
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26-Sep-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] reduce MAX_NR_ZONES: make ZONE_DMA32 optional Make ZONE_DMA32 optional - Add #ifdefs around ZONE_DMA32 specific code and definitions. - Add CONFIG_ZONE_DMA32 config option and use that for x86_64 that alone needs this zone. - Remove the use of CONFIG_DMA_IS_DMA32 and CONFIG_DMA_IS_NORMAL for ia64 and fix up the way per node ZVCs are calculated. - Fall back to prior GFP_ZONEMASK of 0x03 if there is no DMA32 zone. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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2f1b6248 |
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26-Sep-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] reduce MAX_NR_ZONES: use enum to define zones, reformat and comment Use enum for zones and reformat zones dependent information Add comments explaning the use of zones and add a zones_t type for zone numbers. Line up information that will be #ifdefd by the following patches. [akpm@osdl.org: comment cleanups] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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df9ecaba |
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31-Aug-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] ZVC: Scale thresholds depending on the size of the system The ZVC counter update threshold is currently set to a fixed value of 32. This patch sets up the threshold depending on the number of processors and the sizes of the zones in the system. With the current threshold of 32, I was able to observe slight contention when more than 130-140 processors concurrently updated the counters. The contention vanished when I either increased the threshold to 64 or used Andrew's idea of overstepping the interval (see ZVC overstep patch). However, we saw contention again at 220-230 processors. So we need higher values for larger systems. But the current default is already a bit of an overkill for smaller systems. Some systems have tiny zones where precision matters. For example i386 and x86_64 have 16M DMA zones and either 900M ZONE_NORMAL or ZONE_DMA32. These are even present on SMP and NUMA systems. The patch here sets up a threshold based on the number of processors in the system and the size of the zone that these counters are used for. The threshold should grow logarithmically, so we use fls() as an easy approximation. Results of tests on a system with 1024 processors (4TB RAM) The following output is from a test allocating 1GB of memory concurrently on each processor (Forking the process. So contention on mmap_sem and the pte locks is not a factor): X MIN TYPE: CPUS WALL WALL SYS USER TOTCPU fork 1 0.552 0.552 0.540 0.012 0.552 fork 4 0.552 0.548 2.164 0.036 2.200 fork 16 0.564 0.548 8.812 0.164 8.976 fork 128 0.580 0.572 72.204 1.208 73.412 fork 256 1.300 0.660 310.400 2.160 312.560 fork 512 3.512 0.696 1526.836 4.816 1531.652 fork 1020 20.024 0.700 17243.176 6.688 17249.863 So a threshold of 32 is fine up to 128 processors. At 256 processors contention becomes a factor. Overstepping the counter (earlier patch) improves the numbers a bit: fork 4 0.552 0.548 2.164 0.040 2.204 fork 16 0.552 0.548 8.640 0.148 8.788 fork 128 0.556 0.548 69.676 0.956 70.632 fork 256 0.876 0.636 212.468 2.108 214.576 fork 512 2.276 0.672 997.324 4.260 1001.584 fork 1020 13.564 0.680 11586.436 6.088 11592.523 Still contention at 512 and 1020. Contention at 1020 is down by a third. 256 still has a slight bit of contention. After this patch the counter threshold will be set to 125 which reduces contention significantly: fork 128 0.560 0.548 69.776 0.932 70.708 fork 256 0.636 0.556 143.460 2.036 145.496 fork 512 0.640 0.548 284.244 4.236 288.480 fork 1020 1.500 0.588 1326.152 8.892 1335.044 [akpm@osdl.org: !SMP build fix] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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9614634f |
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03-Jul-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] ZVC/zone_reclaim: Leave 1% of unmapped pagecache pages for file I/O It turns out that it is advantageous to leave a small portion of unmapped file backed pages if all of a zone's pages (or almost all pages) are allocated and so the page allocator has to go off-node. This allows recently used file I/O buffers to stay on the node and reduces the times that zone reclaim is invoked if file I/O occurs when we run out of memory in a zone. The problem is that zone reclaim runs too frequently when the page cache is used for file I/O (read write and therefore unmapped pages!) alone and we have almost all pages of the zone allocated. Zone reclaim may remove 32 unmapped pages. File I/O will use these pages for the next read/write requests and the unmapped pages increase. After the zone has filled up again zone reclaim will remove it again after only 32 pages. This cycle is too inefficient and there are potentially too many zone reclaim cycles. With the 1% boundary we may still remove all unmapped pages for file I/O in zone reclaim pass. However. it will take a large number of read and writes to get back to 1% again where we trigger zone reclaim again. The zone reclaim 2.6.16/17 does not show this behavior because we have a 30 second timeout. [akpm@osdl.org: rename the /proc file and the variable] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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ca889e6c |
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30-Jun-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] Use Zoned VM Counters for NUMA statistics The numa statistics are really event counters. But they are per node and so we have had special treatment for these counters through additional fields on the pcp structure. We can now use the per zone nature of the zoned VM counters to realize these. This will shrink the size of the pcp structure on NUMA systems. We will have some room to add additional per zone counters that will all still fit in the same cacheline. Bits Prior pcp size Size after patch We can add ------------------------------------------------------------------ 64 128 bytes (16 words) 80 bytes (10 words) 48 32 76 bytes (19 words) 56 bytes (14 words) 8 (64 byte cacheline) 72 (128 byte) Remove the special statistics for numa and replace them with zoned vm counters. This has the side effect that global sums of these events now show up in /proc/vmstat. Also take the opportunity to move the zone_statistics() function from page_alloc.c into vmstat.c. Discussions: V2 http://marc.theaimsgroup.com/?t=115048227000002&r=1&w=2 Signed-off-by: Christoph Lameter <clameter@sgi.com> Acked-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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d2c5e30c |
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30-Jun-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] zoned vm counters: conversion of nr_bounce to per zone counter Conversion of nr_bounce to a per zone counter nr_bounce is only used for proc output. So it could be left as an event counter. However, the event counters may not be accurate and nr_bounce is categorizing types of pages in a zone. So we really need this to also be a per zone counter. [akpm@osdl.org: bugfix] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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fd39fc85 |
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30-Jun-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] zoned vm counters: conversion of nr_unstable to per zone counter Conversion of nr_unstable to a per zone counter We need to do some special modifications to the nfs code since there are multiple cases of disposition and we need to have a page ref for proper accounting. This converts the last critical page state of the VM and therefore we need to remove several functions that were depending on GET_PAGE_STATE_LAST in order to make the kernel compile again. We are only left with event type counters in page state. [akpm@osdl.org: bugfixes] Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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ce866b34 |
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30-Jun-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] zoned vm counters: conversion of nr_writeback to per zone counter Conversion of nr_writeback to per zone counter. This removes the last page_state counter from arch/i386/mm/pgtable.c so we drop the page_state from there. [akpm@osdl.org: bugfix] Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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b1e7a8fd |
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30-Jun-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] zoned vm counters: conversion of nr_dirty to per zone counter This makes nr_dirty a per zone counter. Looping over all processors is avoided during writeback state determination. The counter aggregation for nr_dirty had to be undone in the NFS layer since we summed up the page counts from multiple zones. Someone more familiar with NFS should probably review what I have done. [akpm@osdl.org: bugfix] Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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df849a15 |
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30-Jun-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] zoned vm counters: conversion of nr_pagetables to per zone counter Conversion of nr_page_table_pages to a per zone counter [akpm@osdl.org: bugfix] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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9a865ffa |
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30-Jun-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] zoned vm counters: conversion of nr_slab to per zone counter - Allows reclaim to access counter without looping over processor counts. - Allows accurate statistics on how many pages are used in a zone by the slab. This may become useful to balance slab allocations over various zones. [akpm@osdl.org: bugfix] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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34aa1330 |
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30-Jun-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] zoned vm counters: zone_reclaim: remove /proc/sys/vm/zone_reclaim_interval The zone_reclaim_interval was necessary because we were not able to determine how many unmapped pages exist in a zone. Therefore we had to scan in intervals to figure out if any pages were unmapped. With the zoned counters and NR_ANON_PAGES we now know the number of pagecache pages and the number of mapped pages in a zone. So we can simply skip the reclaim if there is an insufficient number of unmapped pages. We use SWAP_CLUSTER_MAX as the boundary. Drop all support for /proc/sys/vm/zone_reclaim_interval. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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f3dbd344 |
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30-Jun-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] zoned vm counters: split NR_ANON_PAGES off from NR_FILE_MAPPED The current NR_FILE_MAPPED is used by zone reclaim and the dirty load calculation as the number of mapped pagecache pages. However, that is not true. NR_FILE_MAPPED includes the mapped anonymous pages. This patch separates those and therefore allows an accurate tracking of the anonymous pages per zone. It then becomes possible to determine the number of unmapped pages per zone and we can avoid scanning for unmapped pages if there are none. Also it may now be possible to determine the mapped/unmapped ratio in get_dirty_limit. Isnt the number of anonymous pages irrelevant in that calculation? Note that this will change the meaning of the number of mapped pages reported in /proc/vmstat /proc/meminfo and in the per node statistics. This may affect user space tools that monitor these counters! NR_FILE_MAPPED works like NR_FILE_DIRTY. It is only valid for pagecache pages. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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347ce434 |
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30-Jun-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] zoned vm counters: conversion of nr_pagecache to per zone counter Currently a single atomic variable is used to establish the size of the page cache in the whole machine. The zoned VM counters have the same method of implementation as the nr_pagecache code but also allow the determination of the pagecache size per zone. Remove the special implementation for nr_pagecache and make it a zoned counter named NR_FILE_PAGES. Updates of the page cache counters are always performed with interrupts off. We can therefore use the __ variant here. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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65ba55f5 |
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30-Jun-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] zoned vm counters: convert nr_mapped to per zone counter nr_mapped is important because it allows a determination of how many pages of a zone are not mapped, which would allow a more efficient means of determining when we need to reclaim memory in a zone. We take the nr_mapped field out of the page state structure and define a new per zone counter named NR_FILE_MAPPED (the anonymous pages will be split off from NR_MAPPED in the next patch). We replace the use of nr_mapped in various kernel locations. This avoids the looping over all processors in try_to_free_pages(), writeback, reclaim (swap + zone reclaim). [akpm@osdl.org: bugfix] Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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2244b95a |
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30-Jun-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] zoned vm counters: basic ZVC (zoned vm counter) implementation Per zone counter infrastructure The counters that we currently have for the VM are split per processor. The processor however has not much to do with the zone these pages belong to. We cannot tell f.e. how many ZONE_DMA pages are dirty. So we are blind to potentially inbalances in the usage of memory in various zones. F.e. in a NUMA system we cannot tell how many pages are dirty on a particular node. If we knew then we could put measures into the VM to balance the use of memory between different zones and different nodes in a NUMA system. For example it would be possible to limit the dirty pages per node so that fast local memory is kept available even if a process is dirtying huge amounts of pages. Another example is zone reclaim. We do not know how many unmapped pages exist per zone. So we just have to try to reclaim. If it is not working then we pause and try again later. It would be better if we knew when it makes sense to reclaim unmapped pages from a zone. This patchset allows the determination of the number of unmapped pages per zone. We can remove the zone reclaim interval with the counters introduced here. Futhermore the ability to have various usage statistics available will allow the development of new NUMA balancing algorithms that may be able to improve the decision making in the scheduler of when to move a process to another node and hopefully will also enable automatic page migration through a user space program that can analyse the memory load distribution and then rebalance memory use in order to increase performance. The counter framework here implements differential counters for each processor in struct zone. The differential counters are consolidated when a threshold is exceeded (like done in the current implementation for nr_pageache), when slab reaping occurs or when a consolidation function is called. Consolidation uses atomic operations and accumulates counters per zone in the zone structure and also globally in the vm_stat array. VM functions can access the counts by simply indexing a global or zone specific array. The arrangement of counters in an array also simplifies processing when output has to be generated for /proc/*. Counters can be updated by calling inc/dec_zone_page_state or _inc/dec_zone_page_state analogous to *_page_state. The second group of functions can be called if it is known that interrupts are disabled. Special optimized increment and decrement functions are provided. These can avoid certain checks and use increment or decrement instructions that an architecture may provide. We also add a new CONFIG_DMA_IS_NORMAL that signifies that an architecture can do DMA to all memory and therefore ZONE_NORMAL will not be populated. This is only currently set for IA64 SGI SN2 and currently only affects node_page_state(). In the best case node_page_state can be reduced to retrieving a single counter for the one zone on the node. [akpm@osdl.org: cleanups] [akpm@osdl.org: export vm_stat[] for filesystems] Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
30c253e6 |
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23-Jun-2006 |
Andy Whitcroft <apw@shadowen.org> |
[PATCH] sparsemem: record nid during memory present Record the node id as we mark sections for instantiation. Use this nid during instantiation to direct allocations. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Cc: Mike Kravetz <kravetz@us.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Bob Picco <bob.picco@hp.com> Cc: Jack Steiner <steiner@sgi.com> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Martin Bligh <mbligh@google.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
718127cc |
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23-Jun-2006 |
Yasunori Goto <y-goto@jp.fujitsu.com> |
[PATCH] wait_table and zonelist initializing for memory hotadd: add return code for init_current_empty_zone When add_zone() is called against empty zone (not populated zone), we have to initialize the zone which didn't initialize at boot time. But, init_currently_empty_zone() may fail due to allocation of wait table. So, this patch is to catch its error code. Changes against wait_table is in the next patch. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
02b694de |
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23-Jun-2006 |
Yasunori Goto <y-goto@jp.fujitsu.com> |
[PATCH] wait_table and zonelist initializing for memory hotadd: change name of wait_table_size() This is just to rename from wait_table_size() to wait_table_hash_nr_entries(). Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
93ff66bf |
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04-Jun-2006 |
Ralf Baechle <ralf@linux-mips.org> |
[PATCH] Sparsemem build fix From: Ralf Baechle <ralf@linux-mips.org> <linux/mmzone.h> uses PAGE_SIZE, PAGE_SHIFT from <asm/page.h> without including that header itself. For some sparsemem configurations this may result in build errors like: CC init/initramfs.o In file included from include/linux/gfp.h:4, from include/linux/slab.h:15, from include/linux/percpu.h:4, from include/linux/rcupdate.h:41, from include/linux/dcache.h:10, from include/linux/fs.h:226, from init/initramfs.c:2: include/linux/mmzone.h:498:22: warning: "PAGE_SHIFT" is not defined In file included from include/linux/gfp.h:4, from include/linux/slab.h:15, from include/linux/percpu.h:4, from include/linux/rcupdate.h:41, from include/linux/dcache.h:10, from include/linux/fs.h:226, from init/initramfs.c:2: include/linux/mmzone.h:526: error: `PAGE_SIZE' undeclared here (not in a function) include/linux/mmzone.h: In function `__pfn_to_section': include/linux/mmzone.h:573: error: `PAGE_SHIFT' undeclared (first use in this function) include/linux/mmzone.h:573: error: (Each undeclared identifier is reported only once include/linux/mmzone.h:573: error: for each function it appears in.) include/linux/mmzone.h: In function `pfn_valid': include/linux/mmzone.h:578: error: `PAGE_SHIFT' undeclared (first use in this function) make[1]: *** [init/initramfs.o] Error 1 make: *** [init] Error 2 Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Seems-reasonable-to: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
e984bb43 |
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20-May-2006 |
Bob Picco <bob.picco@hp.com> |
[PATCH] Align the node_mem_map endpoints to a MAX_ORDER boundary Andy added code to buddy allocator which does not require the zone's endpoints to be aligned to MAX_ORDER. An issue is that the buddy allocator requires the node_mem_map's endpoints to be MAX_ORDER aligned. Otherwise __page_find_buddy could compute a buddy not in node_mem_map for partial MAX_ORDER regions at zone's endpoints. page_is_buddy will detect that these pages at endpoints are not PG_buddy (they were zeroed out by bootmem allocator and not part of zone). Of course the negative here is we could waste a little memory but the positive is eliminating all the old checks for zone boundary conditions. SPARSEMEM won't encounter this issue because of MAX_ORDER size constraint when SPARSEMEM is configured. ia64 VIRTUAL_MEM_MAP doesn't need the logic either because the holes and endpoints are handled differently. This leaves checking alloc_remap and other arches which privately allocate for node_mem_map. Signed-off-by: Bob Picco <bob.picco@hp.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
62c4f0a2 |
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25-Apr-2006 |
David Woodhouse <dwmw2@infradead.org> |
Don't include linux/config.h from anywhere else in include/ Signed-off-by: David Woodhouse <dwmw2@infradead.org>
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#
95144c78 |
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27-Mar-2006 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
[PATCH] uninline zone helpers Helper functions for for_each_online_pgdat/for_each_zone look too big to be inlined. Speed of these helper macro itself is not very important. (inner loops are tend to do more work than this) This patch make helper function to be out-of-lined. inline out-of-line .text 005c0680 005bf6a0 005c0680 - 005bf6a0 = FE0 = 4Kbytes. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
ae0f15fb |
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27-Mar-2006 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
[PATCH] for_each_online_pgdat: remove pgdat_list By using for_each_online_pgdat(), pgdat_list is not necessary now. This patch removes it. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
8357f869 |
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27-Mar-2006 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
[PATCH] define for_each_online_pgdat This patch defines for_each_online_pgdat() as a replacement of for_each_pgdat() Now, online nodes are managed by node_online_map. But for_each_pgdat() uses pgdat_link to iterate over all nodes(pgdat). This means management structure for online pgdat is duplicated. I think using node_online_map for for_each_pgdat() is simple and sane rather ather than pgdat_link. New macro is named as for_each_online_pgdat(). Following patch will fix callers of for_each_pgdat(). The bootmem allocater uses for_each_pgdat() before pgdat initialization. I don't think it's sane. Following patch will fix it. Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
a0140c1d |
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27-Mar-2006 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
[PATCH] remove zone_mem_map This patch removes zone_mem_map. pfn_to_page uses pgdat, page_to_pfn uses zone. page_to_pfn can use pgdat instead of zone, which is only one user of zone_mem_map. By modifing it, we can remove zone_mem_map. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Christoph Lameter <christoph@lameter.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
a117e66e |
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27-Mar-2006 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
[PATCH] unify pfn_to_page: generic functions There are 3 memory models, FLATMEM, DISCONTIGMEM, SPARSEMEM. Each arch has its own page_to_pfn(), pfn_to_page() for each models. But most of them can use the same arithmetic. This patch adds asm-generic/memory_model.h, which includes generic page_to_pfn(), pfn_to_page() definitions for each memory model. When CONFIG_OUT_OF_LINE_PFN_TO_PAGE=y, out-of-line functions are used instead of macro. This is enabled by some archs and reduces text size. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ian Molton <spyro@f2s.com> Cc: Mikael Starvik <starvik@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Hirokazu Takata <takata.hirokazu@renesas.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Richard Curnow <rc@rc0.org.uk> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp> Cc: Chris Zankel <chris@zankel.net> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
ce2ea89b |
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01-Feb-2006 |
Andy Whitcroft <apw@shadowen.org> |
[PATCH] GFP_ZONETYPES: calculate from GFP_ZONEMASK GFP_ZONETYPES calculate from GFP_ZONEMASK GFP_ZONETYPES's value is directly related to the value of GFP_ZONEMASK. It takes one of two forms depending whether the top bit of GFP_ZONEMASK is a 'loner'. Supply both forms, enabling the loner. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
79046ae0 |
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01-Feb-2006 |
Andy Whitcroft <apw@shadowen.org> |
[PATCH] GFP_ZONETYPES: add commentry on how to calculate GFP_ZONETYPES define using GFP_ZONEMASK and add commentry Add commentry explaining the optimisation that we can apply to GFP_ZONETYPES when the leftmost bit is a 'loaner', it can only be set in isolation. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
9eeff239 |
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18-Jan-2006 |
Christoph Lameter <clameter@sgi.com> |
[PATCH] Zone reclaim: Reclaim logic Some bits for zone reclaim exists in 2.6.15 but they are not usable. This patch fixes them up, removes unused code and makes zone reclaim usable. Zone reclaim allows the reclaiming of pages from a zone if the number of free pages falls below the watermarks even if other zones still have enough pages available. Zone reclaim is of particular importance for NUMA machines. It can be more beneficial to reclaim a page than taking the performance penalties that come with allocating a page on a remote zone. Zone reclaim is enabled if the maximum distance to another node is higher than RECLAIM_DISTANCE, which may be defined by an arch. By default RECLAIM_DISTANCE is 20. 20 is the distance to another node in the same component (enclosure or motherboard) on IA64. The meaning of the NUMA distance information seems to vary by arch. If zone reclaim is not successful then no further reclaim attempts will occur for a certain time period (ZONE_RECLAIM_INTERVAL). This patch was discussed before. See http://marc.theaimsgroup.com/?l=linux-kernel&m=113519961504207&w=2 http://marc.theaimsgroup.com/?l=linux-kernel&m=113408418232531&w=2 http://marc.theaimsgroup.com/?l=linux-kernel&m=113389027420032&w=2 http://marc.theaimsgroup.com/?l=linux-kernel&m=113380938612205&w=2 Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
1f6818b9 |
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11-Jan-2006 |
Andi Kleen <ak@linux.intel.com> |
[PATCH] x86_64: Minor GFP_DMA32 comment fix Pretty obvious Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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22fc6ecc |
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08-Jan-2006 |
Ravikiran G Thirumalai <kiran@scalex86.org> |
[PATCH] Change maxaligned_in_smp alignemnt macros to internodealigned_in_smp macros ____cacheline_maxaligned_in_smp is currently used to align critical structures and avoid false sharing. It uses per-arch L1_CACHE_SHIFT_MAX and people find L1_CACHE_SHIFT_MAX useless. However, we have been using ____cacheline_maxaligned_in_smp to align structures on the internode cacheline size. As per Andi's suggestion, following patch kills ____cacheline_maxaligned_in_smp and introduces INTERNODE_CACHE_SHIFT, which defaults to L1_CACHE_SHIFT for all arches. Arches needing L3/Internode cacheline alignment can define INTERNODE_CACHE_SHIFT in the arch asm/cache.h. Patch replaces ____cacheline_maxaligned_in_smp with ____cacheline_internodealigned_in_smp With this patch, L1_CACHE_SHIFT_MAX can be killed Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org> Signed-off-by: Shai Fultheim <shai@scalex86.org> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
8ad4b1fb |
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08-Jan-2006 |
Rohit Seth <rohit.seth@intel.com> |
[PATCH] Make high and batch sizes of per_cpu_pagelists configurable As recently there has been lot of traffic on the right values for batch and high water marks for per_cpu_pagelists. This patch makes these two variables configurable through /proc interface. A new tunable /proc/sys/vm/percpu_pagelist_fraction is added. This entry controls the fraction of pages at most in each zone that are allocated for each per cpu page list. The min value for this is 8. It means that we don't allow more than 1/8th of pages in each zone to be allocated in any single per_cpu_pagelist. The batch value of each per cpu pagelist is also updated as a result. It is set to pcp->high/4. The upper limit of batch is (PAGE_SHIFT * 8) Signed-off-by: Rohit Seth <rohit.seth@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
f3fe6512 |
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06-Jan-2006 |
Con Kolivas <kernel@kolivas.org> |
[PATCH] mm: add populated_zone() helper There are numerous places we check whether a zone is populated or not. Provide a helper function to check for populated zones and convert all checks for zone->present_pages. Signed-off-by: Con Kolivas <kernel@kolivas.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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9328b8fa |
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06-Jan-2006 |
Nick Piggin <nickpiggin@yahoo.com.au> |
[PATCH] mm: dma32 zone statistics Add dma32 to zone statistics. Also attempt to arrange struct page_state a bit better (visually). Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
2d92c5c9 |
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06-Jan-2006 |
Nick Piggin <nickpiggin@yahoo.com.au> |
[PATCH] mm: remove pcp low struct per_cpu_pages.low is useless. Remove it. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
161599ff |
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06-Jan-2006 |
Andy Whitcroft <apw@shadowen.org> |
[PATCH] sparsemem: provide pfn_to_nid Before SPARSEMEM is initialised we cannot provide an efficient pfn_to_nid() implmentation; before initialisation is complete we use early_pfn_to_nid() to provide location information. Until recently there was no non-init user of this functionality. Provide a post init pfn_to_nid() implementation. Note that this implmentation assumes that the pfn passed has been validated with pfn_valid(). The current single user of this function already has this check. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
2bdaf115 |
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06-Jan-2006 |
Andy Whitcroft <apw@shadowen.org> |
[PATCH] flatmem split out memory model There are three places we define pfn_to_nid(). Two in linux/mmzone.h and one in asm/mmzone.h. These in essence represent the three memory models. The definition in linux/mmzone.h under !NEED_MULTIPLE_NODES is both the FLATMEM definition and the optimisation for single NUMA nodes; the one under SPARSEMEM is the NUMA sparsemem one; the one in asm/mmzone.h under DISCONTIGMEM is the discontigmem one. This is not in the least bit obvious, particularly the connection between the non-NUMA optimisations and the memory models. Two patches: flatmem-split-out-memory-model: simplifies the selection of pfn_to_nid() implementations. The selection is based primarily off the memory model selected. Optimisations for non-NUMA are applied where needed. sparse-provide-pfn_to_nid: implement pfn_to_nid() for SPARSEMEM This patch: pfn_to_nid is memory model specific The pfn_to_nid() call is memory model specific. It represents the locality identifier for the memory passed. Classically this would be a NUMA node, but not a chunk of memory under DISCONTIGMEM. The SPARSEMEM and FLATMEM memory model non-NUMA versions of pfn_to_nid() are folded together under NEED_MULTIPLE_NODES, while DISCONTIGMEM has its own optimisation. This is all very confusing. This patch splits out each implementation of pfn_to_nid() so that we can see them and the optimisations to each. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
a94b3ab7 |
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06-Jan-2006 |
Mike Kravetz <kravetz@us.ibm.com> |
[PATCH] mm: remove arch independent NODES_SPAN_OTHER_NODES The NODES_SPAN_OTHER_NODES config option was created so that DISCONTIGMEM could handle pSeries numa layouts. However, support for DISCONTIGMEM has been replaced by SPARSEMEM on powerpc. As a result, this config option and supporting code is no longer needed. I have already sent a patch to Paul that removes the option from powerpc specific code. This removes the arch independent piece. Doesn't really matter which is applied first. Signed-off-by: Mike Kravetz <kravetz@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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d5afa6dc |
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06-Jan-2006 |
Andy Whitcroft <apw@shadowen.org> |
[PATCH] mm: pfn_to_pgdat not used in common code pfn_to_pgdat() isn't used in common code. Remove definition. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
9f3fd602 |
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06-Jan-2006 |
Andy Whitcroft <apw@shadowen.org> |
[PATCH] mm: kvaddr_to_nid not used in common code kvaddr_to_nid() isn't used in common code nor in i386 code. Remove these definitions. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
ac3461ad |
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22-Nov-2005 |
Linus Torvalds <torvalds@g5.osdl.org> |
Fix up GFP_ZONEMASK for GFP_DMA32 usage There was some confusion about the different zone usage, this should fix up the resulting mess in the GFP zonemask handling. The different zone usage is still confusing (it's very easy to mix up the individual zone numbers with the GFP zone _list_ numbers), so we might want to clean up some of this in the future, but in the meantime this should fix the actual problems. Acked-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
69d81fcd |
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05-Nov-2005 |
Andi Kleen <ak@linux.intel.com> |
[PATCH] x86_64: Speed up numa_node_id by putting it directly into the PDA Not go from the CPU number to an mapping array. Mode number is often used now in fast paths. This also adds a generic numa_node_id to all the topology includes Suggested by Eric Dumazet Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
07808b74 |
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05-Nov-2005 |
Andi Kleen <ak@linux.intel.com> |
[PATCH] x86_64: Remove obsolete ARCH_HAS_ATOMIC_UNSIGNED and page_flags_t Has been introduced for x86-64 at some point to save memory in struct page, but has been obsolete for some time. Just remove it. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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a2f1b424 |
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05-Nov-2005 |
Andi Kleen <ak@linux.intel.com> |
[PATCH] x86_64: Add 4GB DMA32 zone Add a new 4GB GFP_DMA32 zone between the GFP_DMA and GFP_NORMAL zones. As a bit of historical background: when the x86-64 port was originally designed we had some discussion if we should use a 16MB DMA zone like i386 or a 4GB DMA zone like IA64 or both. Both was ruled out at this point because it was in early 2.4 when VM is still quite shakey and had bad troubles even dealing with one DMA zone. We settled on the 16MB DMA zone mainly because we worried about older soundcards and the floppy. But this has always caused problems since then because device drivers had trouble getting enough DMA able memory. These days the VM works much better and the wide use of NUMA has proven it can deal with many zones successfully. So this patch adds both zones. This helps drivers who need a lot of memory below 4GB because their hardware is not accessing more (graphic drivers - proprietary and free ones, video frame buffer drivers, sound drivers etc.). Previously they could only use IOMMU+16MB GFP_DMA, which was not enough memory. Another common problem is that hardware who has full memory addressing for >4GB misses it for some control structures in memory (like transmit rings or other metadata). They tended to allocate memory in the 16MB GFP_DMA or the IOMMU/swiotlb then using pci_alloc_consistent, but that can tie up a lot of precious 16MB GFPDMA/IOMMU/swiotlb memory (even on AMD systems the IOMMU tends to be quite small) especially if you have many devices. With the new zone pci_alloc_consistent can just put this stuff into memory below 4GB which works better. One argument was still if the zone should be 4GB or 2GB. The main motivation for 2GB would be an unnamed not so unpopular hardware raid controller (mostly found in older machines from a particular four letter company) who has a strange 2GB restriction in firmware. But that one works ok with swiotlb/IOMMU anyways, so it doesn't really need GFP_DMA32. I chose 4GB to be compatible with IA64 and because it seems to be the most common restriction. The new zone is so far added only for x86-64. For other architectures who don't set up this new zone nothing changes. Architectures can set a compatibility define in Kconfig CONFIG_DMA_IS_DMA32 that will define GFP_DMA32 as GFP_DMA. Otherwise it's a nop because on 32bit architectures it's normally not needed because GFP_NORMAL (=0) is DMA able enough. One problem is still that GFP_DMA means different things on different architectures. e.g. some drivers used to have #ifdef ia64 use GFP_DMA (trusting it to be 4GB) #elif __x86_64__ (use other hacks like the swiotlb because 16MB is not enough) ... . This was quite ugly and is now obsolete. These should be now converted to use GFP_DMA32 unconditionally. I haven't done this yet. Or best only use pci_alloc_consistent/dma_alloc_coherent which will use GFP_DMA32 transparently. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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7fb1d9fc |
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13-Nov-2005 |
Rohit Seth <rohit.seth@intel.com> |
[PATCH] mm: __alloc_pages cleanup Clean up of __alloc_pages. Restoration of previous behaviour, plus further cleanups by introducing an 'alloc_flags', removing the last of should_reclaim_zone. Signed-off-by: Rohit Seth <rohit.seth@intel.com> Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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bdc8cb98 |
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29-Oct-2005 |
Dave Hansen <haveblue@us.ibm.com> |
[PATCH] memory hotplug locking: zone span seqlock See the "fixup bad_range()" patch for more information, but this actually creates a the lock to protect things making assumptions about a zone's size staying constant at runtime. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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#
208d54e5 |
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29-Oct-2005 |
Dave Hansen <haveblue@us.ibm.com> |
[PATCH] memory hotplug locking: node_size_lock pgdat->node_size_lock is basically only neeeded in one place in the normal code: show_mem(), which is the arch-specific sysrq-m printing function. Strictly speaking, the architectures not doing memory hotplug do no need this locking in show_mem(). However, they are all included for completeness. This should also make any future consolidation of all of the implementations a little more straightforward. This lock is also held in the sparsemem code during a memory removal, as sections are invalidated. This is the place there pfn_valid() is made false for a memory area that's being removed. The lock is only required when doing pfn_valid() operations on memory which the user does not already have a reference on the page, such as in show_mem(). Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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4ca644d9 |
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29-Oct-2005 |
Dave Hansen <haveblue@us.ibm.com> |
[PATCH] memory hotplug prep: __section_nr helper A little helper that we use in the hotplug code. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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260b2367 |
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21-Oct-2005 |
Al Viro <viro@zeniv.linux.org.uk> |
[PATCH] gfp_t: the rest zone handling, mapping->flags handling Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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28ae55c9 |
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03-Sep-2005 |
Dave Hansen <haveblue@us.ibm.com> |
[PATCH] sparsemem extreme: hotplug preparation This splits up sparse_index_alloc() into two pieces. This is needed because we'll allocate the memory for the second level in a different place from where we actually consume it to keep the allocation from happening underneath a lock Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Bob Picco <bob.picco@hp.com> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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3e347261 |
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03-Sep-2005 |
Bob Picco <bob.picco@hp.com> |
[PATCH] sparsemem extreme implementation With cleanups from Dave Hansen <haveblue@us.ibm.com> SPARSEMEM_EXTREME makes mem_section a one dimensional array of pointers to mem_sections. This two level layout scheme is able to achieve smaller memory requirements for SPARSEMEM with the tradeoff of an additional shift and load when fetching the memory section. The current SPARSEMEM implementation is a one dimensional array of mem_sections which is the default SPARSEMEM configuration. The patch attempts isolates the implementation details of the physical layout of the sparsemem section array. SPARSEMEM_EXTREME requires bootmem to be functioning at the time of memory_present() calls. This is not always feasible, so architectures which do not need it may allocate everything statically by using SPARSEMEM_STATIC. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Bob Picco <bob.picco@hp.com> Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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802f192e |
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03-Sep-2005 |
Bob Picco <bob.picco@hp.com> |
[PATCH] SPARSEMEM EXTREME A new option for SPARSEMEM is ARCH_SPARSEMEM_EXTREME. Architecture platforms with a very sparse physical address space would likely want to select this option. For those architecture platforms that don't select the option, the code generated is equivalent to SPARSEMEM currently in -mm. I'll be posting a patch on ia64 ml which uses this new SPARSEMEM feature. ARCH_SPARSEMEM_EXTREME makes mem_section a one dimensional array of pointers to mem_sections. This two level layout scheme is able to achieve smaller memory requirements for SPARSEMEM with the tradeoff of an additional shift and load when fetching the memory section. The current SPARSEMEM -mm implementation is a one dimensional array of mem_sections which is the default SPARSEMEM configuration. The patch attempts isolates the implementation details of the physical layout of the sparsemem section array. ARCH_SPARSEMEM_EXTREME depends on 64BIT and is by default boolean false. I've boot tested under aim load ia64 configured for ARCH_SPARSEMEM_EXTREME. I've also boot tested a 4 way Opteron machine with !ARCH_SPARSEMEM_EXTREME and tested with aim. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Bob Picco <bob.picco@hp.com> Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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29751f69 |
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23-Jun-2005 |
Andy Whitcroft <apw@shadowen.org> |
[PATCH] sparsemem hotplug base Make sparse's initalization be accessible at runtime. This allows sparse mappings to be created after boot in a hotplug situation. This patch is separated from the previous one just to give an indication how much of the sparse infrastructure is *just* for hotplug memory. The section_mem_map doesn't really store a pointer. It stores something that is convenient to do some math against to get a pointer. It isn't valid to just do *section_mem_map, so I don't think it should be stored as a pointer. There are a couple of things I'd like to store about a section. First of all, the fact that it is !NULL does not mean that it is present. There could be such a combination where section_mem_map *is* NULL, but the math gets you properly to a real mem_map. So, I don't think that check is safe. Since we're storing 32-bit-aligned structures, we have a few bits in the bottom of the pointer to play with. Use one bit to encode whether there's really a mem_map there, and the other one to tell whether there's a valid section there. We need to distinguish between the two because sometimes there's a gap between when a section is discovered to be present and when we can get the mem_map for it. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Bob Picco <bob.picco@hp.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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641c7673 |
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23-Jun-2005 |
Andy Whitcroft <apw@shadowen.org> |
[PATCH] sparsemem swiss cheese numa layouts The part of the sparsemem patch which modifies memmap_init_zone() has recently become a problem. It changes behavior so that there is a call to pfn_to_page() for each individual page inside of a node's range: node_start_pfn through node_end_pfn. It used to simply do this once, at the beginning of the node, but having sparsemem's non-contiguous mem_map[]s inside of a node made it necessary to change. Mike Kravetz recently wrote a patch which made the NUMA code accept some new kinds of layouts. The system's memory was laid out like this, with node 0's memory in two pieces: one before and one after node 1's memory: Node 0: +++++ +++++ Node 1: +++++ Previous behavior before Mike's patch was to assign nodes like this: Node 0: 00000 XXXXX Node 1: 11111 Where the 'X' areas were simply thrown away. The new behavior was to make the pg_data_t span node 0 across all of its areas, including areas that are really node 1's: Node 0: 000000000000000 Node 1: 11111 This wastes a little bit of mem_map space, but ends up being OK, and more fully utilizes the system's memory. memmap_init_zone() initializes all of the "struct page"s for node 0, even for the "hole", but those never get used, because there is no pfn_to_page() that resolves to those pages. However, only calling pfn_to_page() once, memmap_init_zone() always uses the pages that were allocated for node0->node_mem_map because: struct page *start = pfn_to_page(start_pfn); // effectively start = &node->node_mem_map[0] for (page = start; page < (start + size); page++) { init_page_here();... page++; } Slow, and wasteful, but generally harmless. But, modify that to call pfn_to_page() for each loop iteration (like sparsemem does): for (pfn = start_pfn; pfn < < (start_pfn + size); pfn++++) { page = pfn_to_page(pfn); } And you end up trying to initialize node 1's pages too early, along with bogus data from node 0. This patch checks for those weird layouts and declines to touch the pages, making the more frequent pfn_to_page() calls OK to do. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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d41dee36 |
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23-Jun-2005 |
Andy Whitcroft <apw@shadowen.org> |
[PATCH] sparsemem memory model Sparsemem abstracts the use of discontiguous mem_maps[]. This kind of mem_map[] is needed by discontiguous memory machines (like in the old CONFIG_DISCONTIGMEM case) as well as memory hotplug systems. Sparsemem replaces DISCONTIGMEM when enabled, and it is hoped that it can eventually become a complete replacement. A significant advantage over DISCONTIGMEM is that it's completely separated from CONFIG_NUMA. When producing this patch, it became apparent in that NUMA and DISCONTIG are often confused. Another advantage is that sparse doesn't require each NUMA node's ranges to be contiguous. It can handle overlapping ranges between nodes with no problems, where DISCONTIGMEM currently throws away that memory. Sparsemem uses an array to provide different pfn_to_page() translations for each SECTION_SIZE area of physical memory. This is what allows the mem_map[] to be chopped up. In order to do quick pfn_to_page() operations, the section number of the page is encoded in page->flags. Part of the sparsemem infrastructure enables sharing of these bits more dynamically (at compile-time) between the page_zone() and sparsemem operations. However, on 32-bit architectures, the number of bits is quite limited, and may require growing the size of the page->flags type in certain conditions. Several things might force this to occur: a decrease in the SECTION_SIZE (if you want to hotplug smaller areas of memory), an increase in the physical address space, or an increase in the number of used page->flags. One thing to note is that, once sparsemem is present, the NUMA node information no longer needs to be stored in the page->flags. It might provide speed increases on certain platforms and will be stored there if there is room. But, if out of room, an alternate (theoretically slower) mechanism is used. This patch introduces CONFIG_FLATMEM. It is used in almost all cases where there used to be an #ifndef DISCONTIG, because SPARSEMEM and DISCONTIGMEM often have to compile out the same areas of code. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Martin Bligh <mbligh@aracnet.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: Bob Picco <bob.picco@hp.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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b159d43f |
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23-Jun-2005 |
Andy Whitcroft <apw@shadowen.org> |
[PATCH] generify early_pfn_to_nid Provide a default implementation for early_pfn_to_nid returning node 0. Allow architectures to override this with their own implementation out of asm/mmzone.h. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Martin Bligh <mbligh@aracnet.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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93b7504e |
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23-Jun-2005 |
Dave Hansen <haveblue@us.ibm.com> |
[PATCH] Introduce new Kconfig option for NUMA or DISCONTIG There is some confusion that arose when working on SPARSEMEM patch between what is needed for DISCONTIG vs. NUMA. Multiple pg_data_t's are needed for DISCONTIGMEM or NUMA, independently. All of the current NUMA implementations require an implementation of DISCONTIG. Because of this, quite a lot of code which is really needed for NUMA is actually under DISCONTIG #ifdefs. For SPARSEMEM, we changed some of these #ifdefs to CONFIG_NUMA, but that broke the DISCONTIG=y and NUMA=n case. Introducing this new NEED_MULTIPLE_NODES config option allows code that is needed for both NUMA or DISCONTIG to be separated out from code that is specific to DISCONTIG. One great advantage of this approach is that it doesn't require every architecture to be converted over. All of the current implementations should "just work", only the ones implementing SPARSEMEM will have to be fixed up. The change to free_area_init() makes it work inside, or out of the new config option. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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348f8b6c |
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23-Jun-2005 |
Dave Hansen <haveblue@us.ibm.com> |
[PATCH] sparsemem base: reorganize page->flags bit operations Generify the value fields in the page_flags. The aim is to allow the location and size of these fields to be varied. Additionally we want to move away from fixed allocations per field whilst still enforcing the overall bit utilisation limits. We rely on the compiler to spot and optimise the accessor functions. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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408fde81 |
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23-Jun-2005 |
Dave Hansen <haveblue@us.ibm.com> |
[PATCH] remove non-DISCONTIG use of pgdat->node_mem_map This patch effectively eliminates direct use of pgdat->node_mem_map outside of the DISCONTIG code. On a flat memory system, these fields aren't currently used, neither are they on a sparsemem system. There was also a node_mem_map(nid) macro on many architectures. Its use along with the use of ->node_mem_map itself was not consistent. It has been removed in favor of two new, more explicit, arch-independent macros: pgdat_page_nr(pgdat, pagenr) nid_page_nr(nid, pagenr) I called them "pgdat" and "nid" because we overload the term "node" to mean "NUMA node", "DISCONTIG node" or "pg_data_t" in very confusing ways. I believe the newer names are much clearer. These macros can be overridden in the sparsemem case with a theoretically slower operation using node_start_pfn and pfn_to_page(), instead. We could make this the only behavior if people want, but I don't want to change too much at once. One thing at a time. This patch removes more code than it adds. Compile tested on alpha, alpha discontig, arm, arm-discontig, i386, i386 generic, NUMAQ, Summit, ppc64, ppc64 discontig, and x86_64. Full list here: http://sr71.net/patches/2.6.12/2.6.12-rc1-mhp2/configs/ Boot tested on NUMAQ, x86 SMP and ppc64 power4/5 LPARs. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Martin J. Bligh <mbligh@aracnet.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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e7c8d5c9 |
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21-Jun-2005 |
Christoph Lameter <christoph@lameter.com> |
[PATCH] node local per-cpu-pages This patch modifies the way pagesets in struct zone are managed. Each zone has a per-cpu array of pagesets. So any particular CPU has some memory in each zone structure which belongs to itself. Even if that CPU is not local to that zone. So the patch relocates the pagesets for each cpu to the node that is nearest to the cpu instead of allocating the pagesets in the (possibly remote) target zone. This means that the operations to manage pages on remote zone can be done with information available locally. We play a macro trick so that non-NUMA pmachines avoid the additional pointer chase on the page allocator fastpath. AIM7 benchmark on a 32 CPU SGI Altix w/o patches: Tasks jobs/min jti jobs/min/task real cpu 1 484.68 100 484.6769 12.01 1.97 Fri Mar 25 11:01:42 2005 100 27140.46 89 271.4046 21.44 148.71 Fri Mar 25 11:02:04 2005 200 30792.02 82 153.9601 37.80 296.72 Fri Mar 25 11:02:42 2005 300 32209.27 81 107.3642 54.21 451.34 Fri Mar 25 11:03:37 2005 400 34962.83 78 87.4071 66.59 588.97 Fri Mar 25 11:04:44 2005 500 31676.92 75 63.3538 91.87 742.71 Fri Mar 25 11:06:16 2005 600 36032.69 73 60.0545 96.91 885.44 Fri Mar 25 11:07:54 2005 700 35540.43 77 50.7720 114.63 1024.28 Fri Mar 25 11:09:49 2005 800 33906.70 74 42.3834 137.32 1181.65 Fri Mar 25 11:12:06 2005 900 34120.67 73 37.9119 153.51 1325.26 Fri Mar 25 11:14:41 2005 1000 34802.37 74 34.8024 167.23 1465.26 Fri Mar 25 11:17:28 2005 with slab API changes and pageset patch: Tasks jobs/min jti jobs/min/task real cpu 1 485.00 100 485.0000 12.00 1.96 Fri Mar 25 11:46:18 2005 100 28000.96 89 280.0096 20.79 150.45 Fri Mar 25 11:46:39 2005 200 32285.80 79 161.4290 36.05 293.37 Fri Mar 25 11:47:16 2005 300 40424.15 84 134.7472 43.19 438.42 Fri Mar 25 11:47:59 2005 400 39155.01 79 97.8875 59.46 590.05 Fri Mar 25 11:48:59 2005 500 37881.25 82 75.7625 76.82 730.19 Fri Mar 25 11:50:16 2005 600 39083.14 78 65.1386 89.35 872.79 Fri Mar 25 11:51:46 2005 700 38627.83 77 55.1826 105.47 1022.46 Fri Mar 25 11:53:32 2005 800 39631.94 78 49.5399 117.48 1169.94 Fri Mar 25 11:55:30 2005 900 36903.70 79 41.0041 141.94 1310.78 Fri Mar 25 11:57:53 2005 1000 36201.23 77 36.2012 160.77 1458.31 Fri Mar 25 12:00:34 2005 Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Shobhit Dayal <shobhit@calsoftinc.com> Signed-off-by: Shai Fultheim <Shai@Scalex86.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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1e7e5a90 |
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21-Jun-2005 |
Martin Hicks <mort@sgi.com> |
[PATCH] VM: rate limit early reclaim When early zone reclaim is turned on the LRU is scanned more frequently when a zone is low on memory. This limits when the zone reclaim can be called by skipping the scan if another thread (either via kswapd or sync reclaim) is already reclaiming from the zone. Signed-off-by: Martin Hicks <mort@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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753ee728 |
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21-Jun-2005 |
Martin Hicks <mort@sgi.com> |
[PATCH] VM: early zone reclaim This is the core of the (much simplified) early reclaim. The goal of this patch is to reclaim some easily-freed pages from a zone before falling back onto another zone. One of the major uses of this is NUMA machines. With the default allocator behavior the allocator would look for memory in another zone, which might be off-node, before trying to reclaim from the current zone. This adds a zone tuneable to enable early zone reclaim. It is selected on a per-zone basis and is turned on/off via syscall. Adding some extra throttling on the reclaim was also required (patch 4/4). Without the machine would grind to a crawl when doing a "make -j" kernel build. Even with this patch the System Time is higher on average, but it seems tolerable. Here are some numbers for kernbench runs on a 2-node, 4cpu, 8Gig RAM Altix in the "make -j" run: wall user sys %cpu ctx sw. sleeps ---- ---- --- ---- ------ ------ No patch 1009 1384 847 258 298170 504402 w/patch, no reclaim 880 1376 667 288 254064 396745 w/patch & reclaim 1079 1385 926 252 291625 548873 These numbers are the average of 2 runs of 3 "make -j" runs done right after system boot. Run-to-run variability for "make -j" is huge, so these numbers aren't terribly useful except to seee that with reclaim the benchmark still finishes in a reasonable amount of time. I also looked at the NUMA hit/miss stats for the "make -j" runs and the reclaim doesn't make any difference when the machine is thrashing away. Doing a "make -j8" on a single node that is filled with page cache pages takes 700 seconds with reclaim turned on and 735 seconds without reclaim (due to remote memory accesses). The simple zone_reclaim syscall program is at http://www.bork.org/~mort/sgi/zone_reclaim.c Signed-off-by: Martin Hicks <mort@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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39c715b7 |
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21-Jun-2005 |
Ingo Molnar <mingo@elte.hu> |
[PATCH] smp_processor_id() cleanup This patch implements a number of smp_processor_id() cleanup ideas that Arjan van de Ven and I came up with. The previous __smp_processor_id/_smp_processor_id/smp_processor_id API spaghetti was hard to follow both on the implementational and on the usage side. Some of the complexity arose from picking wrong names, some of the complexity comes from the fact that not all architectures defined __smp_processor_id. In the new code, there are two externally visible symbols: - smp_processor_id(): debug variant. - raw_smp_processor_id(): nondebug variant. Replaces all existing uses of _smp_processor_id() and __smp_processor_id(). Defined by every SMP architecture in include/asm-*/smp.h. There is one new internal symbol, dependent on DEBUG_PREEMPT: - debug_smp_processor_id(): internal debug variant, mapped to smp_processor_id(). Also, i moved debug_smp_processor_id() from lib/kernel_lock.c into a new lib/smp_processor_id.c file. All related comments got updated and/or clarified. I have build/boot tested the following 8 .config combinations on x86: {SMP,UP} x {PREEMPT,!PREEMPT} x {DEBUG_PREEMPT,!DEBUG_PREEMPT} I have also build/boot tested x64 on UP/PREEMPT/DEBUG_PREEMPT. (Other architectures are untested, but should work just fine.) Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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1da177e4 |
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16-Apr-2005 |
Linus Torvalds <torvalds@ppc970.osdl.org> |
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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