Searched hist:715 (Results 251 - 271 of 271) sorted by relevance
/linux-master/fs/f2fs/ | ||
H A D | file.c | diff 0a2aa8fb Fri Jul 08 18:42:21 MDT 2016 Jaegeuk Kim <jaegeuk@kernel.org> f2fs: refactor __exchange_data_block for speed up This reduces the elapsed time to do xfstests/generic/017. Before: 715 s After: 458 s Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> |
/linux-master/net/core/ | ||
H A D | skbuff.c | diff 715dc1f3 Wed May 02 17:33:21 MDT 2012 Eric Dumazet <edumazet@google.com> net: Fix truesize accounting in skb_gro_receive() GRO is very optimistic in skb truesize estimates, only taking into account the used part of fragments. Be conservative, and use more precise computation, so that bloated GRO skbs can be collapsed eventually. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Alexander Duyck <alexander.h.duyck@intel.com> Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Acked-by: Alexander Duyck <alexander.h.duyck@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
/linux-master/net/bluetooth/ | ||
H A D | mgmt.c | diff 715a5bf2 Wed Jan 09 06:29:34 MST 2013 Johan Hedberg <johan.hedberg@intel.com> Bluetooth: Fix missing command complete for mgmt_load_long_term_keys All management events are expected to indicate successful completion through a command complete event, however the load long term keys command was missing this. This patch adds the missing event. Signed-off-by: Johan Hedberg <johan.hedberg@intel.com> Acked-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk> |
/linux-master/tools/lib/bpf/ | ||
H A D | libbpf.c | diff 715f8db9 Tue Nov 03 04:21:05 MST 2015 Namhyung Kim <namhyung@kernel.org> tools lib bpf: Fix compiler warning on CentOS 6 CC libbpf.o cc1: warnings being treated as errors libbpf.c: In function 'bpf_program__title': libbpf.c:1037: error: declaration of 'dup' shadows a global declaration /usr/include/unistd.h:528: error: shadowed declaration is here mv: cannot stat `./.libbpf.o.tmp': No such file or directory make[3]: *** [libbpf.o] Error 1 make[2]: *** [libbpf-in.o] Error 2 make[1]: *** [/linux/tools/lib/bpf/libbpf.a] Error 2 make[1]: *** Waiting for unfinished jobs.... Signed-off-by: Namhyung Kim <namhyung@kernel.org> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1446549665-2342-1-git-send-email-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
/linux-master/kernel/bpf/ | ||
H A D | syscall.c | diff 715d82ba Wed Jan 03 12:05:46 MST 2024 Jiri Olsa <olsajiri@gmail.com> bpf: Fix re-attachment branch in bpf_tracing_prog_attach The following case can cause a crash due to missing attach_btf: 1) load rawtp program 2) load fentry program with rawtp as target_fd 3) create tracing link for fentry program with target_fd = 0 4) repeat 3 In the end we have: - prog->aux->dst_trampoline == NULL - tgt_prog == NULL (because we did not provide target_fd to link_create) - prog->aux->attach_btf == NULL (the program was loaded with attach_prog_fd=X) - the program was loaded for tgt_prog but we have no way to find out which one BUG: kernel NULL pointer dereference, address: 0000000000000058 Call Trace: <TASK> ? __die+0x20/0x70 ? page_fault_oops+0x15b/0x430 ? fixup_exception+0x22/0x330 ? exc_page_fault+0x6f/0x170 ? asm_exc_page_fault+0x22/0x30 ? bpf_tracing_prog_attach+0x279/0x560 ? btf_obj_id+0x5/0x10 bpf_tracing_prog_attach+0x439/0x560 __sys_bpf+0x1cf4/0x2de0 __x64_sys_bpf+0x1c/0x30 do_syscall_64+0x41/0xf0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 Return -EINVAL in this situation. Fixes: f3a95075549e0 ("bpf: Allow trampoline re-attach for tracing and lsm programs") Cc: stable@vger.kernel.org Signed-off-by: Jiri Olsa <olsajiri@gmail.com> Acked-by: Jiri Olsa <olsajiri@gmail.com> Acked-by: Song Liu <song@kernel.org> Signed-off-by: Dmitrii Dolgov <9erthalion6@gmail.com> Link: https://lore.kernel.org/r/20240103190559.14750-4-9erthalion6@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> |
/linux-master/net/ipv6/ | ||
H A D | route.c | diff 8b40a9d5 Mon Dec 13 19:58:06 MST 2021 Eric Dumazet <edumazet@google.com> ipv6: use GFP_ATOMIC in rt6_probe() syzbot reminded me that rt6_probe() can run from atomic contexts. stack backtrace: CPU: 1 PID: 7461 Comm: syz-executor.2 Not tainted 5.16.0-rc4-next-20211210-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_usage_bug kernel/locking/lockdep.c:203 [inline] valid_state kernel/locking/lockdep.c:3945 [inline] mark_lock_irq kernel/locking/lockdep.c:4148 [inline] mark_lock.cold+0x61/0x8e kernel/locking/lockdep.c:4605 mark_usage kernel/locking/lockdep.c:4500 [inline] __lock_acquire+0x11d5/0x54a0 kernel/locking/lockdep.c:4981 lock_acquire kernel/locking/lockdep.c:5639 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5604 __fs_reclaim_acquire mm/page_alloc.c:4550 [inline] fs_reclaim_acquire+0x115/0x160 mm/page_alloc.c:4564 might_alloc include/linux/sched/mm.h:253 [inline] slab_pre_alloc_hook mm/slab.h:739 [inline] slab_alloc_node mm/slub.c:3145 [inline] slab_alloc mm/slub.c:3239 [inline] kmem_cache_alloc_trace+0x3b/0x2c0 mm/slub.c:3256 kmalloc include/linux/slab.h:581 [inline] kzalloc include/linux/slab.h:715 [inline] ref_tracker_alloc+0xe1/0x430 lib/ref_tracker.c:74 netdev_tracker_alloc include/linux/netdevice.h:3860 [inline] dev_hold_track include/linux/netdevice.h:3877 [inline] rt6_probe net/ipv6/route.c:661 [inline] find_match.part.0+0xac9/0xd00 net/ipv6/route.c:752 find_match net/ipv6/route.c:825 [inline] __find_rr_leaf+0x17f/0xd20 net/ipv6/route.c:826 find_rr_leaf net/ipv6/route.c:847 [inline] rt6_select net/ipv6/route.c:891 [inline] fib6_table_lookup+0x649/0xa20 net/ipv6/route.c:2185 ip6_pol_route+0x1c5/0x11e0 net/ipv6/route.c:2221 pol_lookup_func include/net/ip6_fib.h:580 [inline] fib6_rule_lookup+0x52a/0x6f0 net/ipv6/fib6_rules.c:120 ip6_route_output_flags_noref+0x2e2/0x380 net/ipv6/route.c:2629 ip6_route_output_flags+0x72/0x320 net/ipv6/route.c:2642 ip6_route_output include/net/ip6_route.h:98 [inline] ip6_dst_lookup_tail+0x5ab/0x1620 net/ipv6/ip6_output.c:1070 ip6_dst_lookup_flow+0x8c/0x1d0 net/ipv6/ip6_output.c:1200 geneve_get_v6_dst+0x46f/0x9a0 drivers/net/geneve.c:858 geneve6_xmit_skb drivers/net/geneve.c:991 [inline] geneve_xmit+0x520/0x3530 drivers/net/geneve.c:1074 __netdev_start_xmit include/linux/netdevice.h:4685 [inline] netdev_start_xmit include/linux/netdevice.h:4699 [inline] xmit_one net/core/dev.c:3473 [inline] dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3489 __dev_queue_xmit+0x2983/0x3640 net/core/dev.c:4112 neigh_resolve_output net/core/neighbour.c:1522 [inline] neigh_resolve_output+0x50e/0x820 net/core/neighbour.c:1502 neigh_output include/net/neighbour.h:541 [inline] ip6_finish_output2+0x56e/0x14f0 net/ipv6/ip6_output.c:126 __ip6_finish_output net/ipv6/ip6_output.c:191 [inline] __ip6_finish_output+0x61e/0xe80 net/ipv6/ip6_output.c:170 ip6_finish_output+0x32/0x200 net/ipv6/ip6_output.c:201 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x1e4/0x530 net/ipv6/ip6_output.c:224 dst_output include/net/dst.h:451 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] ndisc_send_skb+0xa99/0x17f0 net/ipv6/ndisc.c:508 ndisc_send_rs+0x12e/0x6f0 net/ipv6/ndisc.c:702 addrconf_rs_timer+0x3f2/0x820 net/ipv6/addrconf.c:3898 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097 </IRQ> Fixes: fb67510ba9bd ("ipv6: add net device refcount tracker to rt6_probe_deferred()") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Link: https://lore.kernel.org/r/20211214025806.3456382-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
/linux-master/tools/perf/util/ | ||
H A D | session.c | diff 207b5792 Sun Jul 01 16:11:37 MDT 2012 David Ahern <dsahern@gmail.com> perf kvm: Fix regression with guest machine creation Commit 743eb868657bdb1b26c7b24077ca21c67c82c777 reworked when the machines were created. Prior to this commit guest machines could be created in perf_event__process_kernel_mmap() while processing kernel MMAP events. This commit assumes that the machines exist by the time perf_session_deliver_event is called (e.g., during processing of build id events) - which is not always correct. One example is the use of default guest args (--guestkallsyms and --guestmodules) for short times where no samples hit within a guest module. For this case no build id is added to the file header. No build id == no machine created. That leads to the next example -- the use of no-buildid (-B) on the record for all perf-kvm invocations. In both cases perf report dies with a SEGFAULT of the form: (gdb) bt 0 0x000000000046dd7b in machine__mmap_name (self=0x0, bf=0x7fffffffbd20 "q\021", size=4096) at util/map.c:715 1 0x0000000000444161 in perf_event__process_kernel_mmap (tool=0x7fffffffdd80, event=0x7ffff7fb4120, machine=0x0) at util/event.c:562 2 0x0000000000444642 in perf_event__process_mmap (tool=0x7fffffffdd80, event=0x7ffff7fb4120, sample=0x7fffffffd210, machine=0x0) at util/event.c:668 3 0x0000000000470e0b in perf_session_deliver_event (session=0x915ca0, event=0x7ffff7fb4120, sample=0x7fffffffd210, tool=0x7fffffffdd80, file_offset=8480) at util/session.c:979 4 0x000000000047032e in flush_sample_queue (s=0x915ca0, tool=0x7fffffffdd80) at util/session.c:679 5 0x0000000000471c8d in __perf_session__process_events (session=0x915ca0, data_offset=400, data_size=150448, file_size=150848, tool= 0x7fffffffdd80) at util/session.c:1363 6 0x0000000000471d42 in perf_session__process_events (self=0x915ca0, tool=0x7fffffffdd80) at util/session.c:1379 7 0x000000000042484a in __cmd_report (rep=0x7fffffffdd80) at builtin-report.c:368 8 0x0000000000425bf1 in cmd_report (argc=0, argv=0x915b00, prefix=0x0) at builtin-report.c:756 9 0x0000000000438505 in __cmd_report (argc=4, argv=0x7fffffffe260) at builtin-kvm.c:84 10 0x000000000043882a in cmd_kvm (argc=4, argv=0x7fffffffe260, prefix=0x0) at builtin-kvm.c:131 11 0x00000000004152cd in run_builtin (p=0x7a54e8, argc=9, argv=0x7fffffffe260) at perf.c:273 12 0x00000000004154c7 in handle_internal_command (argc=9, argv=0x7fffffffe260) at perf.c:345 13 0x0000000000415613 in run_argv (argcp=0x7fffffffe14c, argv=0x7fffffffe140) at perf.c:389 14 0x0000000000415899 in main (argc=9, argv=0x7fffffffe260) at perf.c:487 Fix by allowing the machine to be created in perf_session_deliver_event. Tested with --guestmount option and default guest args, with and without -B arg on record for both and for short (10 seconds) and long (10 minutes) windows. Reported-by: Pradeep Kumar Surisetty <psuriset@linux.vnet.ibm.com> Signed-off-by: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Pradeep Kumar Surisetty <psuriset@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1341180697-64515-1-git-send-email-dsahern@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
/linux-master/drivers/nvme/host/ | ||
H A D | core.c | diff 715ea9e0 Tue Nov 07 09:27:34 MST 2017 Christoph Hellwig <hch@lst.de> nvme: fix and clarify the check for missing metadata Update the check in nvme_setup_rw for missing metadata so that it is together with the other metadata handling, does not contain impossible to reach conditions and warns if we get an impossible requests for a (non-PI) metadata-enabled namespace when CONFIG_BLK_DEV_INTEGRITY is not set. Also add a little helper that checks if a given metadata configuration contains protection information Signed-off-by: Christoph Hellwig <hch@lst.de> Reported-by: Javier González <jg@lightnvm.io> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> |
/linux-master/mm/ | ||
H A D | hugetlb.c | diff d2cf88c2 Wed Oct 18 20:31:03 MDT 2023 Mike Kravetz <mike.kravetz@oracle.com> hugetlb: optimize update_and_free_pages_bulk to avoid lock cycles Patch series "Batch hugetlb vmemmap modification operations", v8. When hugetlb vmemmap optimization was introduced, the overhead of enabling the option was measured as described in commit 426e5c429d16 [1]. The summary states that allocating a hugetlb page should be ~2x slower with optimization and freeing a hugetlb page should be ~2-3x slower. Such overhead was deemed an acceptable trade off for the memory savings obtained by freeing vmemmap pages. It was recently reported that the overhead associated with enabling vmemmap optimization could be as high as 190x for hugetlb page allocations. Yes, 190x! Some actual numbers from other environments are: Bare Metal 8 socket Intel(R) Xeon(R) CPU E7-8895 ------------------------------------------------ Unmodified next-20230824, vm.hugetlb_optimize_vmemmap = 0 time echo 500000 > .../hugepages-2048kB/nr_hugepages real 0m4.119s time echo 0 > .../hugepages-2048kB/nr_hugepages real 0m4.477s Unmodified next-20230824, vm.hugetlb_optimize_vmemmap = 1 time echo 500000 > .../hugepages-2048kB/nr_hugepages real 0m28.973s time echo 0 > .../hugepages-2048kB/nr_hugepages real 0m36.748s VM with 252 vcpus on host with 2 socket AMD EPYC 7J13 Milan ----------------------------------------------------------- Unmodified next-20230824, vm.hugetlb_optimize_vmemmap = 0 time echo 524288 > .../hugepages-2048kB/nr_hugepages real 0m2.463s time echo 0 > .../hugepages-2048kB/nr_hugepages real 0m2.931s Unmodified next-20230824, vm.hugetlb_optimize_vmemmap = 1 time echo 524288 > .../hugepages-2048kB/nr_hugepages real 2m27.609s time echo 0 > .../hugepages-2048kB/nr_hugepages real 2m29.924s In the VM environment, the slowdown of enabling hugetlb vmemmap optimization resulted in allocation times being 61x slower. A quick profile showed that the vast majority of this overhead was due to TLB flushing. Each time we modify the kernel pagetable we need to flush the TLB. For each hugetlb that is optimized, there could be potentially two TLB flushes performed. One for the vmemmap pages associated with the hugetlb page, and potentially another one if the vmemmap pages are mapped at the PMD level and must be split. The TLB flushes required for the kernel pagetable, result in a broadcast IPI with each CPU having to flush a range of pages, or do a global flush if a threshold is exceeded. So, the flush time increases with the number of CPUs. In addition, in virtual environments the broadcast IPI can’t be accelerated by hypervisor hardware and leads to traps that need to wakeup/IPI all vCPUs which is very expensive. Because of this the slowdown in virtual environments is even worse than bare metal as the number of vCPUS/CPUs is increased. The following series attempts to reduce amount of time spent in TLB flushing. The idea is to batch the vmemmap modification operations for multiple hugetlb pages. Instead of doing one or two TLB flushes for each page, we do two TLB flushes for each batch of pages. One flush after splitting pages mapped at the PMD level, and another after remapping vmemmap associated with all hugetlb pages. Results of such batching are as follows: Bare Metal 8 socket Intel(R) Xeon(R) CPU E7-8895 ------------------------------------------------ next-20230824 + Batching patches, vm.hugetlb_optimize_vmemmap = 0 time echo 500000 > .../hugepages-2048kB/nr_hugepages real 0m4.719s time echo 0 > .../hugepages-2048kB/nr_hugepages real 0m4.245s next-20230824 + Batching patches, vm.hugetlb_optimize_vmemmap = 1 time echo 500000 > .../hugepages-2048kB/nr_hugepages real 0m7.267s time echo 0 > .../hugepages-2048kB/nr_hugepages real 0m13.199s VM with 252 vcpus on host with 2 socket AMD EPYC 7J13 Milan ----------------------------------------------------------- next-20230824 + Batching patches, vm.hugetlb_optimize_vmemmap = 0 time echo 524288 > .../hugepages-2048kB/nr_hugepages real 0m2.715s time echo 0 > .../hugepages-2048kB/nr_hugepages real 0m3.186s next-20230824 + Batching patches, vm.hugetlb_optimize_vmemmap = 1 time echo 524288 > .../hugepages-2048kB/nr_hugepages real 0m4.799s time echo 0 > .../hugepages-2048kB/nr_hugepages real 0m5.273s With batching, results are back in the 2-3x slowdown range. This patch (of 8): update_and_free_pages_bulk is designed to free a list of hugetlb pages back to their associated lower level allocators. This may require allocating vmemmmap pages associated with each hugetlb page. The hugetlb page destructor must be changed before pages are freed to lower level allocators. However, the destructor must be changed under the hugetlb lock. This means there is potentially one lock cycle per page. Minimize the number of lock cycles in update_and_free_pages_bulk by: 1) allocating necessary vmemmap for all hugetlb pages on the list 2) take hugetlb lock and clear destructor for all pages on the list 3) free all pages on list back to low level allocators Link: https://lkml.kernel.org/r/20231019023113.345257-1-mike.kravetz@oracle.com Link: https://lkml.kernel.org/r/20231019023113.345257-2-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Acked-by: James Houghton <jthoughton@google.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Barry Song <21cnbao@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Konrad Dybcio <konradybcio@kernel.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Oscar Salvador <osalvador@suse.de> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Usama Arif <usama.arif@bytedance.com> Cc: Xiongchun Duan <duanxiongchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> diff 715cbfd6 Fri May 07 13:05:06 MDT 2021 Matthew Wilcox (Oracle) <willy@infradead.org> mm/migrate: Add folio_migrate_copy() This is the folio equivalent of migrate_page_copy(), which is retained as a wrapper for filesystems which are not yet converted to folios. Also convert copy_huge_page() to folio_copy(). Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> |
H A D | huge_memory.c | diff 444eb2a4 Thu Mar 17 15:19:23 MDT 2016 Mel Gorman <mgorman@techsingularity.net> mm: thp: set THP defrag by default to madvise and add a stall-free defrag option THP defrag is enabled by default to direct reclaim/compact but not wake kswapd in the event of a THP allocation failure. The problem is that THP allocation requests potentially enter reclaim/compaction. This potentially incurs a severe stall that is not guaranteed to be offset by reduced TLB misses. While there has been considerable effort to reduce the impact of reclaim/compaction, it is still a high cost and workloads that should fit in memory fail to do so. Specifically, a simple anon/file streaming workload will enter direct reclaim on NUMA at least even though the working set size is 80% of RAM. It's been years and it's time to throw in the towel. First, this patch defines THP defrag as follows; madvise: A failed allocation will direct reclaim/compact if the application requests it never: Neither reclaim/compact nor wake kswapd defer: A failed allocation will wake kswapd/kcompactd always: A failed allocation will direct reclaim/compact (historical behaviour) khugepaged defrag will enter direct/reclaim but not wake kswapd. Next it sets the default defrag option to be "madvise" to only enter direct reclaim/compaction for applications that specifically requested it. Lastly, it removes a check from the page allocator slowpath that is related to __GFP_THISNODE to allow "defer" to work. The callers that really cares are slub/slab and they are updated accordingly. The slab one may be surprising because it also corrects a comment as kswapd was never woken up by that path. This means that a THP fault will no longer stall for most applications by default and the ideal for most users that get THP if they are immediately available. There are still options for users that prefer a stall at startup of a new application by either restoring historical behaviour with "always" or pick a half-way point with "defer" where kswapd does some of the work in the background and wakes kcompactd if necessary. THP defrag for khugepaged remains enabled and will enter direct/reclaim but no wakeup kswapd or kcompactd. After this patch a THP allocation failure will quickly fallback and rely on khugepaged to recover the situation at some time in the future. In some cases, this will reduce THP usage but the benefit of THP is hard to measure and not a universal win where as a stall to reclaim/compaction is definitely measurable and can be painful. The first test for this is using "usemem" to read a large file and write a large anonymous mapping (to avoid the zero page) multiple times. The total size of the mappings is 80% of RAM and the benchmark simply measures how long it takes to complete. It uses multiple threads to see if that is a factor. On UMA, the performance is almost identical so is not reported but on NUMA, we see this usemem 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 Amean System-1 102.86 ( 0.00%) 46.81 ( 54.50%) Amean System-4 37.85 ( 0.00%) 34.02 ( 10.12%) Amean System-7 48.12 ( 0.00%) 46.89 ( 2.56%) Amean System-12 51.98 ( 0.00%) 56.96 ( -9.57%) Amean System-21 80.16 ( 0.00%) 79.05 ( 1.39%) Amean System-30 110.71 ( 0.00%) 107.17 ( 3.20%) Amean System-48 127.98 ( 0.00%) 124.83 ( 2.46%) Amean Elapsd-1 185.84 ( 0.00%) 105.51 ( 43.23%) Amean Elapsd-4 26.19 ( 0.00%) 25.58 ( 2.33%) Amean Elapsd-7 21.65 ( 0.00%) 21.62 ( 0.16%) Amean Elapsd-12 18.58 ( 0.00%) 17.94 ( 3.43%) Amean Elapsd-21 17.53 ( 0.00%) 16.60 ( 5.33%) Amean Elapsd-30 17.45 ( 0.00%) 17.13 ( 1.84%) Amean Elapsd-48 15.40 ( 0.00%) 15.27 ( 0.82%) For a single thread, the benchmark completes 43.23% faster with this patch applied with smaller benefits as the thread increases. Similar, notice the large reduction in most cases in system CPU usage. The overall CPU time is 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 User 10357.65 10438.33 System 3988.88 3543.94 Elapsed 2203.01 1634.41 Which is substantial. Now, the reclaim figures 4.4.0 4.4.0 kcompactd-v1r1nodefrag-v1r3 Minor Faults 128458477 278352931 Major Faults 2174976 225 Swap Ins 16904701 0 Swap Outs 17359627 0 Allocation stalls 43611 0 DMA allocs 0 0 DMA32 allocs 19832646 19448017 Normal allocs 614488453 580941839 Movable allocs 0 0 Direct pages scanned 24163800 0 Kswapd pages scanned 0 0 Kswapd pages reclaimed 0 0 Direct pages reclaimed 20691346 0 Compaction stalls 42263 0 Compaction success 938 0 Compaction failures 41325 0 This patch eliminates almost all swapping and direct reclaim activity. There is still overhead but it's from NUMA balancing which does not identify that it's pointless trying to do anything with this workload. I also tried the thpscale benchmark which forces a corner case where compaction can be used heavily and measures the latency of whether base or huge pages were used thpscale Fault Latencies 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 Amean fault-base-1 5288.84 ( 0.00%) 2817.12 ( 46.73%) Amean fault-base-3 6365.53 ( 0.00%) 3499.11 ( 45.03%) Amean fault-base-5 6526.19 ( 0.00%) 4363.06 ( 33.15%) Amean fault-base-7 7142.25 ( 0.00%) 4858.08 ( 31.98%) Amean fault-base-12 13827.64 ( 0.00%) 10292.11 ( 25.57%) Amean fault-base-18 18235.07 ( 0.00%) 13788.84 ( 24.38%) Amean fault-base-24 21597.80 ( 0.00%) 24388.03 (-12.92%) Amean fault-base-30 26754.15 ( 0.00%) 19700.55 ( 26.36%) Amean fault-base-32 26784.94 ( 0.00%) 19513.57 ( 27.15%) Amean fault-huge-1 4223.96 ( 0.00%) 2178.57 ( 48.42%) Amean fault-huge-3 2194.77 ( 0.00%) 2149.74 ( 2.05%) Amean fault-huge-5 2569.60 ( 0.00%) 2346.95 ( 8.66%) Amean fault-huge-7 3612.69 ( 0.00%) 2997.70 ( 17.02%) Amean fault-huge-12 3301.75 ( 0.00%) 6727.02 (-103.74%) Amean fault-huge-18 6696.47 ( 0.00%) 6685.72 ( 0.16%) Amean fault-huge-24 8000.72 ( 0.00%) 9311.43 (-16.38%) Amean fault-huge-30 13305.55 ( 0.00%) 9750.45 ( 26.72%) Amean fault-huge-32 9981.71 ( 0.00%) 10316.06 ( -3.35%) The average time to fault pages is substantially reduced in the majority of caseds but with the obvious caveat that fewer THPs are actually used in this adverse workload 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 Percentage huge-1 0.71 ( 0.00%) 14.04 (1865.22%) Percentage huge-3 10.77 ( 0.00%) 33.05 (206.85%) Percentage huge-5 60.39 ( 0.00%) 38.51 (-36.23%) Percentage huge-7 45.97 ( 0.00%) 34.57 (-24.79%) Percentage huge-12 68.12 ( 0.00%) 40.07 (-41.17%) Percentage huge-18 64.93 ( 0.00%) 47.82 (-26.35%) Percentage huge-24 62.69 ( 0.00%) 44.23 (-29.44%) Percentage huge-30 43.49 ( 0.00%) 55.38 ( 27.34%) Percentage huge-32 50.72 ( 0.00%) 51.90 ( 2.35%) 4.4.0 4.4.0 kcompactd-v1r1nodefrag-v1r3 Minor Faults 37429143 47564000 Major Faults 1916 1558 Swap Ins 1466 1079 Swap Outs 2936863 149626 Allocation stalls 62510 3 DMA allocs 0 0 DMA32 allocs 6566458 6401314 Normal allocs 216361697 216538171 Movable allocs 0 0 Direct pages scanned 25977580 17998 Kswapd pages scanned 0 3638931 Kswapd pages reclaimed 0 207236 Direct pages reclaimed 8833714 88 Compaction stalls 103349 5 Compaction success 270 4 Compaction failures 103079 1 Note again that while this does swap as it's an aggressive workload, the direct relcim activity and allocation stalls is substantially reduced. There is some kswapd activity but ftrace showed that the kswapd activity was due to normal wakeups from 4K pages being allocated. Compaction-related stalls and activity are almost eliminated. I also tried the stutter benchmark. For this, I do not have figures for NUMA but it's something that does impact UMA so I'll report what is available stutter 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 Min mmap 7.3571 ( 0.00%) 7.3438 ( 0.18%) 1st-qrtle mmap 7.5278 ( 0.00%) 17.9200 (-138.05%) 2nd-qrtle mmap 7.6818 ( 0.00%) 21.6055 (-181.25%) 3rd-qrtle mmap 11.0889 ( 0.00%) 21.8881 (-97.39%) Max-90% mmap 27.8978 ( 0.00%) 22.1632 ( 20.56%) Max-93% mmap 28.3202 ( 0.00%) 22.3044 ( 21.24%) Max-95% mmap 28.5600 ( 0.00%) 22.4580 ( 21.37%) Max-99% mmap 29.6032 ( 0.00%) 25.5216 ( 13.79%) Max mmap 4109.7289 ( 0.00%) 4813.9832 (-17.14%) Mean mmap 12.4474 ( 0.00%) 19.3027 (-55.07%) This benchmark is trying to fault an anonymous mapping while there is a heavy IO load -- a scenario that desktop users used to complain about frequently. This shows a mix because the ideal case of mapping with THP is not hit as often. However, note that 99% of the mappings complete 13.79% faster. The CPU usage here is particularly interesting 4.4.0 4.4.0 kcompactd-v1r1nodefrag-v1r3 User 67.50 0.99 System 1327.88 91.30 Elapsed 2079.00 2128.98 And once again we look at the reclaim figures 4.4.0 4.4.0 kcompactd-v1r1nodefrag-v1r3 Minor Faults 335241922 1314582827 Major Faults 715 819 Swap Ins 0 0 Swap Outs 0 0 Allocation stalls 532723 0 DMA allocs 0 0 DMA32 allocs 1822364341 1177950222 Normal allocs 1815640808 1517844854 Movable allocs 0 0 Direct pages scanned 21892772 0 Kswapd pages scanned 20015890 41879484 Kswapd pages reclaimed 19961986 41822072 Direct pages reclaimed 21892741 0 Compaction stalls 1065755 0 Compaction success 514 0 Compaction failures 1065241 0 Allocation stalls and all direct reclaim activity is eliminated as well as compaction-related stalls. THP gives impressive gains in some cases but only if they are quickly available. We're not going to reach the point where they are completely free so lets take the costs out of the fast paths finally and defer the cost to kswapd, kcompactd and khugepaged where it belongs. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@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> diff 4a6c1297 Wed Dec 12 14:50:47 MST 2012 Kirill A. Shutemov <kirill.shutemov@linux.intel.com> thp: huge zero page: basic preparation During testing I noticed big (up to 2.5 times) memory consumption overhead on some workloads (e.g. ft.A from NPB) if THP is enabled. The main reason for that big difference is lacking zero page in THP case. We have to allocate a real page on read page fault. A program to demonstrate the issue: #include <assert.h> #include <stdlib.h> #include <unistd.h> #define MB 1024*1024 int main(int argc, char **argv) { char *p; int i; posix_memalign((void **)&p, 2 * MB, 200 * MB); for (i = 0; i < 200 * MB; i+= 4096) assert(p[i] == 0); pause(); return 0; } With thp-never RSS is about 400k, but with thp-always it's 200M. After the patcheset thp-always RSS is 400k too. Design overview. Huge zero page (hzp) is a non-movable huge page (2M on x86-64) filled with zeros. The way how we allocate it changes in the patchset: - [01/10] simplest way: hzp allocated on boot time in hugepage_init(); - [09/10] lazy allocation on first use; - [10/10] lockless refcounting + shrinker-reclaimable hzp; We setup it in do_huge_pmd_anonymous_page() if area around fault address is suitable for THP and we've got read page fault. If we fail to setup hzp (ENOMEM) we fallback to handle_pte_fault() as we normally do in THP. On wp fault to hzp we allocate real memory for the huge page and clear it. If ENOMEM, graceful fallback: we create a new pmd table and set pte around fault address to newly allocated normal (4k) page. All other ptes in the pmd set to normal zero page. We cannot split hzp (and it's bug if we try), but we can split the pmd which points to it. On splitting the pmd we create a table with all ptes set to normal zero page. === By hpa's request I've tried alternative approach for hzp implementation (see Virtual huge zero page patchset): pmd table with all entries set to zero page. This way should be more cache friendly, but it increases TLB pressure. The problem with virtual huge zero page: it requires per-arch enabling. We need a way to mark that pmd table has all ptes set to zero page. Some numbers to compare two implementations (on 4s Westmere-EX): Mirobenchmark1 ============== test: posix_memalign((void **)&p, 2 * MB, 8 * GB); for (i = 0; i < 100; i++) { assert(memcmp(p, p + 4*GB, 4*GB) == 0); asm volatile ("": : :"memory"); } hzp: Performance counter stats for './test_memcmp' (5 runs): 32356.272845 task-clock # 0.998 CPUs utilized ( +- 0.13% ) 40 context-switches # 0.001 K/sec ( +- 0.94% ) 0 CPU-migrations # 0.000 K/sec 4,218 page-faults # 0.130 K/sec ( +- 0.00% ) 76,712,481,765 cycles # 2.371 GHz ( +- 0.13% ) [83.31%] 36,279,577,636 stalled-cycles-frontend # 47.29% frontend cycles idle ( +- 0.28% ) [83.35%] 1,684,049,110 stalled-cycles-backend # 2.20% backend cycles idle ( +- 2.96% ) [66.67%] 134,355,715,816 instructions # 1.75 insns per cycle # 0.27 stalled cycles per insn ( +- 0.10% ) [83.35%] 13,526,169,702 branches # 418.039 M/sec ( +- 0.10% ) [83.31%] 1,058,230 branch-misses # 0.01% of all branches ( +- 0.91% ) [83.36%] 32.413866442 seconds time elapsed ( +- 0.13% ) vhzp: Performance counter stats for './test_memcmp' (5 runs): 30327.183829 task-clock # 0.998 CPUs utilized ( +- 0.13% ) 38 context-switches # 0.001 K/sec ( +- 1.53% ) 0 CPU-migrations # 0.000 K/sec 4,218 page-faults # 0.139 K/sec ( +- 0.01% ) 71,964,773,660 cycles # 2.373 GHz ( +- 0.13% ) [83.35%] 31,191,284,231 stalled-cycles-frontend # 43.34% frontend cycles idle ( +- 0.40% ) [83.32%] 773,484,474 stalled-cycles-backend # 1.07% backend cycles idle ( +- 6.61% ) [66.67%] 134,982,215,437 instructions # 1.88 insns per cycle # 0.23 stalled cycles per insn ( +- 0.11% ) [83.32%] 13,509,150,683 branches # 445.447 M/sec ( +- 0.11% ) [83.34%] 1,017,667 branch-misses # 0.01% of all branches ( +- 1.07% ) [83.32%] 30.381324695 seconds time elapsed ( +- 0.13% ) Mirobenchmark2 ============== test: posix_memalign((void **)&p, 2 * MB, 8 * GB); for (i = 0; i < 1000; i++) { char *_p = p; while (_p < p+4*GB) { assert(*_p == *(_p+4*GB)); _p += 4096; asm volatile ("": : :"memory"); } } hzp: Performance counter stats for 'taskset -c 0 ./test_memcmp2' (5 runs): 3505.727639 task-clock # 0.998 CPUs utilized ( +- 0.26% ) 9 context-switches # 0.003 K/sec ( +- 4.97% ) 4,384 page-faults # 0.001 M/sec ( +- 0.00% ) 8,318,482,466 cycles # 2.373 GHz ( +- 0.26% ) [33.31%] 5,134,318,786 stalled-cycles-frontend # 61.72% frontend cycles idle ( +- 0.42% ) [33.32%] 2,193,266,208 stalled-cycles-backend # 26.37% backend cycles idle ( +- 5.51% ) [33.33%] 9,494,670,537 instructions # 1.14 insns per cycle # 0.54 stalled cycles per insn ( +- 0.13% ) [41.68%] 2,108,522,738 branches # 601.451 M/sec ( +- 0.09% ) [41.68%] 158,746 branch-misses # 0.01% of all branches ( +- 1.60% ) [41.71%] 3,168,102,115 L1-dcache-loads # 903.693 M/sec ( +- 0.11% ) [41.70%] 1,048,710,998 L1-dcache-misses # 33.10% of all L1-dcache hits ( +- 0.11% ) [41.72%] 1,047,699,685 LLC-load # 298.854 M/sec ( +- 0.03% ) [33.38%] 2,287 LLC-misses # 0.00% of all LL-cache hits ( +- 8.27% ) [33.37%] 3,166,187,367 dTLB-loads # 903.147 M/sec ( +- 0.02% ) [33.35%] 4,266,538 dTLB-misses # 0.13% of all dTLB cache hits ( +- 0.03% ) [33.33%] 3.513339813 seconds time elapsed ( +- 0.26% ) vhzp: Performance counter stats for 'taskset -c 0 ./test_memcmp2' (5 runs): 27313.891128 task-clock # 0.998 CPUs utilized ( +- 0.24% ) 62 context-switches # 0.002 K/sec ( +- 0.61% ) 4,384 page-faults # 0.160 K/sec ( +- 0.01% ) 64,747,374,606 cycles # 2.370 GHz ( +- 0.24% ) [33.33%] 61,341,580,278 stalled-cycles-frontend # 94.74% frontend cycles idle ( +- 0.26% ) [33.33%] 56,702,237,511 stalled-cycles-backend # 87.57% backend cycles idle ( +- 0.07% ) [33.33%] 10,033,724,846 instructions # 0.15 insns per cycle # 6.11 stalled cycles per insn ( +- 0.09% ) [41.65%] 2,190,424,932 branches # 80.195 M/sec ( +- 0.12% ) [41.66%] 1,028,630 branch-misses # 0.05% of all branches ( +- 1.50% ) [41.66%] 3,302,006,540 L1-dcache-loads # 120.891 M/sec ( +- 0.11% ) [41.68%] 271,374,358 L1-dcache-misses # 8.22% of all L1-dcache hits ( +- 0.04% ) [41.66%] 20,385,476 LLC-load # 0.746 M/sec ( +- 1.64% ) [33.34%] 76,754 LLC-misses # 0.38% of all LL-cache hits ( +- 2.35% ) [33.34%] 3,309,927,290 dTLB-loads # 121.181 M/sec ( +- 0.03% ) [33.34%] 2,098,967,427 dTLB-misses # 63.41% of all dTLB cache hits ( +- 0.03% ) [33.34%] 27.364448741 seconds time elapsed ( +- 0.24% ) === I personally prefer implementation present in this patchset. It doesn't touch arch-specific code. This patch: Huge zero page (hzp) is a non-movable huge page (2M on x86-64) filled with zeros. For now let's allocate the page on hugepage_init(). We'll switch to lazy allocation later. We are not going to map the huge zero page until we can handle it properly on all code paths. is_huge_zero_{pfn,pmd}() functions will be used by following patches to check whether the pfn/pmd is huge zero page. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: "H. Peter Anvin" <hpa@linux.intel.com> Cc: Mel Gorman <mel@csn.ul.ie> 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> |
H A D | migrate.c | diff 715cbfd6 Fri May 07 13:05:06 MDT 2021 Matthew Wilcox (Oracle) <willy@infradead.org> mm/migrate: Add folio_migrate_copy() This is the folio equivalent of migrate_page_copy(), which is retained as a wrapper for filesystems which are not yet converted to folios. Also convert copy_huge_page() to folio_copy(). Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> |
H A D | rmap.c | diff 7dc7c5ef Thu Dec 07 09:12:02 MST 2023 Ryan Roberts <ryan.roberts@arm.com> mm: allow deferred splitting of arbitrary anon large folios Patch series "Multi-size THP for anonymous memory", v9. A series to implement multi-size THP (mTHP) for anonymous memory (previously called "small-sized THP" and "large anonymous folios"). The objective of this is to improve performance by allocating larger chunks of memory during anonymous page faults: 1) Since SW (the kernel) is dealing with larger chunks of memory than base pages, there are efficiency savings to be had; fewer page faults, batched PTE and RMAP manipulation, reduced lru list, etc. In short, we reduce kernel overhead. This should benefit all architectures. 2) Since we are now mapping physically contiguous chunks of memory, we can take advantage of HW TLB compression techniques. A reduction in TLB pressure speeds up kernel and user space. arm64 systems have 2 mechanisms to coalesce TLB entries; "the contiguous bit" (architectural) and HPA (uarch). This version incorporates David's feedback on the core patches (#3, #4) and adds some RB and TB tags (see change log for details). By default, the existing behaviour (and performance) is maintained. The user must explicitly enable multi-size THP to see the performance benefit. This is done via a new sysfs interface (as recommended by David Hildenbrand - thanks to David for the suggestion)! This interface is inspired by the existing per-hugepage-size sysfs interface used by hugetlb, provides full backwards compatibility with the existing PMD-size THP interface, and provides a base for future extensibility. See [9] for detailed discussion of the interface. This series is based on mm-unstable (715b67adf4c8). Prerequisites ============= I'm removing this section on the basis that I don't believe what we were previously calling prerequisites are really prerequisites anymore. We originally defined them when mTHP was a compile-time feature. There is now a runtime control to opt-in to mTHP; when disabled, correctness and performance are as before. When enabled, the code is still correct/robust, but in the absence of the one remaining item (compaction) there may be a performance impact in some corners. See the old list in the v8 cover letter at [8]. And a longer explanation of my thinking here [10]. SUMMARY: I don't think we should hold this series up, waiting for the items on the prerequisites list. I believe this series should be ready now so hopefully can be added to mm-unstable for some testing, then fingers crossed for v6.8. Testing ======= The series includes patches for mm selftests to enlighten the cow and khugepaged tests to explicitly test with multi-size THP, in the same way that PMD-sized THP is tested. The new tests all pass, and no regressions are observed in the mm selftest suite. I've also run my usual kernel compilation and java script benchmarks without any issues. Refer to my performance numbers posted with v6 [6]. (These are for multi-size THP only - they do not include the arm64 contpte follow-on series). John Hubbard at Nvidia has indicated dramatic 10x performance improvements for some workloads at [11]. (Observed using v6 of this series as well as the arm64 contpte series). Kefeng Wang at Huawei has also indicated he sees improvements at [12] although there are some latency regressions also. I've also checked that there is no regression in the write fault path when mTHP is disabled using a microbenchmark. I ran it for a baseline kernel, as well as v8 and v9. I repeated on Ampere Altra (bare metal) and Apple M2 (VM): | | m2 vm | altra | |--------------|---------------------|---------------------| | kernel | mean | std_rel | mean | std_rel | |--------------|----------|----------|----------|----------| | baseline | 0.000% | 0.341% | 0.000% | 3.581% | | anonfolio-v8 | 0.005% | 0.272% | 5.068% | 1.128% | | anonfolio-v9 | -0.013% | 0.442% | 0.107% | 1.788% | There is no measurable difference on M2, but altra has a slow down in v8 which is fixed in v9 by moving the THP order check to be inline within thp_vma_allowable_orders(), as suggested by David. This patch (of 10): In preparation for the introduction of anonymous multi-size THP, we would like to be able to split them when they have unmapped subpages, in order to free those unused pages under memory pressure. So remove the artificial requirement that the large folio needed to be at least PMD-sized. Link: https://lkml.kernel.org/r/20231207161211.2374093-1-ryan.roberts@arm.com Link: https://lkml.kernel.org/r/20231207161211.2374093-2-ryan.roberts@arm.com Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Yu Zhao <yuzhao@google.com> Reviewed-by: Yin Fengwei <fengwei.yin@intel.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Barry Song <v-songbaohua@oppo.com> Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com> Tested-by: John Hubbard <jhubbard@nvidia.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Itaru Kitayama <itaru.kitayama@gmail.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
H A D | slub.c | diff 444eb2a4 Thu Mar 17 15:19:23 MDT 2016 Mel Gorman <mgorman@techsingularity.net> mm: thp: set THP defrag by default to madvise and add a stall-free defrag option THP defrag is enabled by default to direct reclaim/compact but not wake kswapd in the event of a THP allocation failure. The problem is that THP allocation requests potentially enter reclaim/compaction. This potentially incurs a severe stall that is not guaranteed to be offset by reduced TLB misses. While there has been considerable effort to reduce the impact of reclaim/compaction, it is still a high cost and workloads that should fit in memory fail to do so. Specifically, a simple anon/file streaming workload will enter direct reclaim on NUMA at least even though the working set size is 80% of RAM. It's been years and it's time to throw in the towel. First, this patch defines THP defrag as follows; madvise: A failed allocation will direct reclaim/compact if the application requests it never: Neither reclaim/compact nor wake kswapd defer: A failed allocation will wake kswapd/kcompactd always: A failed allocation will direct reclaim/compact (historical behaviour) khugepaged defrag will enter direct/reclaim but not wake kswapd. Next it sets the default defrag option to be "madvise" to only enter direct reclaim/compaction for applications that specifically requested it. Lastly, it removes a check from the page allocator slowpath that is related to __GFP_THISNODE to allow "defer" to work. The callers that really cares are slub/slab and they are updated accordingly. The slab one may be surprising because it also corrects a comment as kswapd was never woken up by that path. This means that a THP fault will no longer stall for most applications by default and the ideal for most users that get THP if they are immediately available. There are still options for users that prefer a stall at startup of a new application by either restoring historical behaviour with "always" or pick a half-way point with "defer" where kswapd does some of the work in the background and wakes kcompactd if necessary. THP defrag for khugepaged remains enabled and will enter direct/reclaim but no wakeup kswapd or kcompactd. After this patch a THP allocation failure will quickly fallback and rely on khugepaged to recover the situation at some time in the future. In some cases, this will reduce THP usage but the benefit of THP is hard to measure and not a universal win where as a stall to reclaim/compaction is definitely measurable and can be painful. The first test for this is using "usemem" to read a large file and write a large anonymous mapping (to avoid the zero page) multiple times. The total size of the mappings is 80% of RAM and the benchmark simply measures how long it takes to complete. It uses multiple threads to see if that is a factor. On UMA, the performance is almost identical so is not reported but on NUMA, we see this usemem 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 Amean System-1 102.86 ( 0.00%) 46.81 ( 54.50%) Amean System-4 37.85 ( 0.00%) 34.02 ( 10.12%) Amean System-7 48.12 ( 0.00%) 46.89 ( 2.56%) Amean System-12 51.98 ( 0.00%) 56.96 ( -9.57%) Amean System-21 80.16 ( 0.00%) 79.05 ( 1.39%) Amean System-30 110.71 ( 0.00%) 107.17 ( 3.20%) Amean System-48 127.98 ( 0.00%) 124.83 ( 2.46%) Amean Elapsd-1 185.84 ( 0.00%) 105.51 ( 43.23%) Amean Elapsd-4 26.19 ( 0.00%) 25.58 ( 2.33%) Amean Elapsd-7 21.65 ( 0.00%) 21.62 ( 0.16%) Amean Elapsd-12 18.58 ( 0.00%) 17.94 ( 3.43%) Amean Elapsd-21 17.53 ( 0.00%) 16.60 ( 5.33%) Amean Elapsd-30 17.45 ( 0.00%) 17.13 ( 1.84%) Amean Elapsd-48 15.40 ( 0.00%) 15.27 ( 0.82%) For a single thread, the benchmark completes 43.23% faster with this patch applied with smaller benefits as the thread increases. Similar, notice the large reduction in most cases in system CPU usage. The overall CPU time is 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 User 10357.65 10438.33 System 3988.88 3543.94 Elapsed 2203.01 1634.41 Which is substantial. Now, the reclaim figures 4.4.0 4.4.0 kcompactd-v1r1nodefrag-v1r3 Minor Faults 128458477 278352931 Major Faults 2174976 225 Swap Ins 16904701 0 Swap Outs 17359627 0 Allocation stalls 43611 0 DMA allocs 0 0 DMA32 allocs 19832646 19448017 Normal allocs 614488453 580941839 Movable allocs 0 0 Direct pages scanned 24163800 0 Kswapd pages scanned 0 0 Kswapd pages reclaimed 0 0 Direct pages reclaimed 20691346 0 Compaction stalls 42263 0 Compaction success 938 0 Compaction failures 41325 0 This patch eliminates almost all swapping and direct reclaim activity. There is still overhead but it's from NUMA balancing which does not identify that it's pointless trying to do anything with this workload. I also tried the thpscale benchmark which forces a corner case where compaction can be used heavily and measures the latency of whether base or huge pages were used thpscale Fault Latencies 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 Amean fault-base-1 5288.84 ( 0.00%) 2817.12 ( 46.73%) Amean fault-base-3 6365.53 ( 0.00%) 3499.11 ( 45.03%) Amean fault-base-5 6526.19 ( 0.00%) 4363.06 ( 33.15%) Amean fault-base-7 7142.25 ( 0.00%) 4858.08 ( 31.98%) Amean fault-base-12 13827.64 ( 0.00%) 10292.11 ( 25.57%) Amean fault-base-18 18235.07 ( 0.00%) 13788.84 ( 24.38%) Amean fault-base-24 21597.80 ( 0.00%) 24388.03 (-12.92%) Amean fault-base-30 26754.15 ( 0.00%) 19700.55 ( 26.36%) Amean fault-base-32 26784.94 ( 0.00%) 19513.57 ( 27.15%) Amean fault-huge-1 4223.96 ( 0.00%) 2178.57 ( 48.42%) Amean fault-huge-3 2194.77 ( 0.00%) 2149.74 ( 2.05%) Amean fault-huge-5 2569.60 ( 0.00%) 2346.95 ( 8.66%) Amean fault-huge-7 3612.69 ( 0.00%) 2997.70 ( 17.02%) Amean fault-huge-12 3301.75 ( 0.00%) 6727.02 (-103.74%) Amean fault-huge-18 6696.47 ( 0.00%) 6685.72 ( 0.16%) Amean fault-huge-24 8000.72 ( 0.00%) 9311.43 (-16.38%) Amean fault-huge-30 13305.55 ( 0.00%) 9750.45 ( 26.72%) Amean fault-huge-32 9981.71 ( 0.00%) 10316.06 ( -3.35%) The average time to fault pages is substantially reduced in the majority of caseds but with the obvious caveat that fewer THPs are actually used in this adverse workload 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 Percentage huge-1 0.71 ( 0.00%) 14.04 (1865.22%) Percentage huge-3 10.77 ( 0.00%) 33.05 (206.85%) Percentage huge-5 60.39 ( 0.00%) 38.51 (-36.23%) Percentage huge-7 45.97 ( 0.00%) 34.57 (-24.79%) Percentage huge-12 68.12 ( 0.00%) 40.07 (-41.17%) Percentage huge-18 64.93 ( 0.00%) 47.82 (-26.35%) Percentage huge-24 62.69 ( 0.00%) 44.23 (-29.44%) Percentage huge-30 43.49 ( 0.00%) 55.38 ( 27.34%) Percentage huge-32 50.72 ( 0.00%) 51.90 ( 2.35%) 4.4.0 4.4.0 kcompactd-v1r1nodefrag-v1r3 Minor Faults 37429143 47564000 Major Faults 1916 1558 Swap Ins 1466 1079 Swap Outs 2936863 149626 Allocation stalls 62510 3 DMA allocs 0 0 DMA32 allocs 6566458 6401314 Normal allocs 216361697 216538171 Movable allocs 0 0 Direct pages scanned 25977580 17998 Kswapd pages scanned 0 3638931 Kswapd pages reclaimed 0 207236 Direct pages reclaimed 8833714 88 Compaction stalls 103349 5 Compaction success 270 4 Compaction failures 103079 1 Note again that while this does swap as it's an aggressive workload, the direct relcim activity and allocation stalls is substantially reduced. There is some kswapd activity but ftrace showed that the kswapd activity was due to normal wakeups from 4K pages being allocated. Compaction-related stalls and activity are almost eliminated. I also tried the stutter benchmark. For this, I do not have figures for NUMA but it's something that does impact UMA so I'll report what is available stutter 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 Min mmap 7.3571 ( 0.00%) 7.3438 ( 0.18%) 1st-qrtle mmap 7.5278 ( 0.00%) 17.9200 (-138.05%) 2nd-qrtle mmap 7.6818 ( 0.00%) 21.6055 (-181.25%) 3rd-qrtle mmap 11.0889 ( 0.00%) 21.8881 (-97.39%) Max-90% mmap 27.8978 ( 0.00%) 22.1632 ( 20.56%) Max-93% mmap 28.3202 ( 0.00%) 22.3044 ( 21.24%) Max-95% mmap 28.5600 ( 0.00%) 22.4580 ( 21.37%) Max-99% mmap 29.6032 ( 0.00%) 25.5216 ( 13.79%) Max mmap 4109.7289 ( 0.00%) 4813.9832 (-17.14%) Mean mmap 12.4474 ( 0.00%) 19.3027 (-55.07%) This benchmark is trying to fault an anonymous mapping while there is a heavy IO load -- a scenario that desktop users used to complain about frequently. This shows a mix because the ideal case of mapping with THP is not hit as often. However, note that 99% of the mappings complete 13.79% faster. The CPU usage here is particularly interesting 4.4.0 4.4.0 kcompactd-v1r1nodefrag-v1r3 User 67.50 0.99 System 1327.88 91.30 Elapsed 2079.00 2128.98 And once again we look at the reclaim figures 4.4.0 4.4.0 kcompactd-v1r1nodefrag-v1r3 Minor Faults 335241922 1314582827 Major Faults 715 819 Swap Ins 0 0 Swap Outs 0 0 Allocation stalls 532723 0 DMA allocs 0 0 DMA32 allocs 1822364341 1177950222 Normal allocs 1815640808 1517844854 Movable allocs 0 0 Direct pages scanned 21892772 0 Kswapd pages scanned 20015890 41879484 Kswapd pages reclaimed 19961986 41822072 Direct pages reclaimed 21892741 0 Compaction stalls 1065755 0 Compaction success 514 0 Compaction failures 1065241 0 Allocation stalls and all direct reclaim activity is eliminated as well as compaction-related stalls. THP gives impressive gains in some cases but only if they are quickly available. We're not going to reach the point where they are completely free so lets take the costs out of the fast paths finally and defer the cost to kswapd, kcompactd and khugepaged where it belongs. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@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> |
H A D | memcontrol.c | diff 715a5ee8 Wed Nov 02 14:38:18 MDT 2011 KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> memcg: fix oom schedule_timeout() Before calling schedule_timeout(), task state should be changed. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
H A D | page_alloc.c | diff 444eb2a4 Thu Mar 17 15:19:23 MDT 2016 Mel Gorman <mgorman@techsingularity.net> mm: thp: set THP defrag by default to madvise and add a stall-free defrag option THP defrag is enabled by default to direct reclaim/compact but not wake kswapd in the event of a THP allocation failure. The problem is that THP allocation requests potentially enter reclaim/compaction. This potentially incurs a severe stall that is not guaranteed to be offset by reduced TLB misses. While there has been considerable effort to reduce the impact of reclaim/compaction, it is still a high cost and workloads that should fit in memory fail to do so. Specifically, a simple anon/file streaming workload will enter direct reclaim on NUMA at least even though the working set size is 80% of RAM. It's been years and it's time to throw in the towel. First, this patch defines THP defrag as follows; madvise: A failed allocation will direct reclaim/compact if the application requests it never: Neither reclaim/compact nor wake kswapd defer: A failed allocation will wake kswapd/kcompactd always: A failed allocation will direct reclaim/compact (historical behaviour) khugepaged defrag will enter direct/reclaim but not wake kswapd. Next it sets the default defrag option to be "madvise" to only enter direct reclaim/compaction for applications that specifically requested it. Lastly, it removes a check from the page allocator slowpath that is related to __GFP_THISNODE to allow "defer" to work. The callers that really cares are slub/slab and they are updated accordingly. The slab one may be surprising because it also corrects a comment as kswapd was never woken up by that path. This means that a THP fault will no longer stall for most applications by default and the ideal for most users that get THP if they are immediately available. There are still options for users that prefer a stall at startup of a new application by either restoring historical behaviour with "always" or pick a half-way point with "defer" where kswapd does some of the work in the background and wakes kcompactd if necessary. THP defrag for khugepaged remains enabled and will enter direct/reclaim but no wakeup kswapd or kcompactd. After this patch a THP allocation failure will quickly fallback and rely on khugepaged to recover the situation at some time in the future. In some cases, this will reduce THP usage but the benefit of THP is hard to measure and not a universal win where as a stall to reclaim/compaction is definitely measurable and can be painful. The first test for this is using "usemem" to read a large file and write a large anonymous mapping (to avoid the zero page) multiple times. The total size of the mappings is 80% of RAM and the benchmark simply measures how long it takes to complete. It uses multiple threads to see if that is a factor. On UMA, the performance is almost identical so is not reported but on NUMA, we see this usemem 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 Amean System-1 102.86 ( 0.00%) 46.81 ( 54.50%) Amean System-4 37.85 ( 0.00%) 34.02 ( 10.12%) Amean System-7 48.12 ( 0.00%) 46.89 ( 2.56%) Amean System-12 51.98 ( 0.00%) 56.96 ( -9.57%) Amean System-21 80.16 ( 0.00%) 79.05 ( 1.39%) Amean System-30 110.71 ( 0.00%) 107.17 ( 3.20%) Amean System-48 127.98 ( 0.00%) 124.83 ( 2.46%) Amean Elapsd-1 185.84 ( 0.00%) 105.51 ( 43.23%) Amean Elapsd-4 26.19 ( 0.00%) 25.58 ( 2.33%) Amean Elapsd-7 21.65 ( 0.00%) 21.62 ( 0.16%) Amean Elapsd-12 18.58 ( 0.00%) 17.94 ( 3.43%) Amean Elapsd-21 17.53 ( 0.00%) 16.60 ( 5.33%) Amean Elapsd-30 17.45 ( 0.00%) 17.13 ( 1.84%) Amean Elapsd-48 15.40 ( 0.00%) 15.27 ( 0.82%) For a single thread, the benchmark completes 43.23% faster with this patch applied with smaller benefits as the thread increases. Similar, notice the large reduction in most cases in system CPU usage. The overall CPU time is 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 User 10357.65 10438.33 System 3988.88 3543.94 Elapsed 2203.01 1634.41 Which is substantial. Now, the reclaim figures 4.4.0 4.4.0 kcompactd-v1r1nodefrag-v1r3 Minor Faults 128458477 278352931 Major Faults 2174976 225 Swap Ins 16904701 0 Swap Outs 17359627 0 Allocation stalls 43611 0 DMA allocs 0 0 DMA32 allocs 19832646 19448017 Normal allocs 614488453 580941839 Movable allocs 0 0 Direct pages scanned 24163800 0 Kswapd pages scanned 0 0 Kswapd pages reclaimed 0 0 Direct pages reclaimed 20691346 0 Compaction stalls 42263 0 Compaction success 938 0 Compaction failures 41325 0 This patch eliminates almost all swapping and direct reclaim activity. There is still overhead but it's from NUMA balancing which does not identify that it's pointless trying to do anything with this workload. I also tried the thpscale benchmark which forces a corner case where compaction can be used heavily and measures the latency of whether base or huge pages were used thpscale Fault Latencies 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 Amean fault-base-1 5288.84 ( 0.00%) 2817.12 ( 46.73%) Amean fault-base-3 6365.53 ( 0.00%) 3499.11 ( 45.03%) Amean fault-base-5 6526.19 ( 0.00%) 4363.06 ( 33.15%) Amean fault-base-7 7142.25 ( 0.00%) 4858.08 ( 31.98%) Amean fault-base-12 13827.64 ( 0.00%) 10292.11 ( 25.57%) Amean fault-base-18 18235.07 ( 0.00%) 13788.84 ( 24.38%) Amean fault-base-24 21597.80 ( 0.00%) 24388.03 (-12.92%) Amean fault-base-30 26754.15 ( 0.00%) 19700.55 ( 26.36%) Amean fault-base-32 26784.94 ( 0.00%) 19513.57 ( 27.15%) Amean fault-huge-1 4223.96 ( 0.00%) 2178.57 ( 48.42%) Amean fault-huge-3 2194.77 ( 0.00%) 2149.74 ( 2.05%) Amean fault-huge-5 2569.60 ( 0.00%) 2346.95 ( 8.66%) Amean fault-huge-7 3612.69 ( 0.00%) 2997.70 ( 17.02%) Amean fault-huge-12 3301.75 ( 0.00%) 6727.02 (-103.74%) Amean fault-huge-18 6696.47 ( 0.00%) 6685.72 ( 0.16%) Amean fault-huge-24 8000.72 ( 0.00%) 9311.43 (-16.38%) Amean fault-huge-30 13305.55 ( 0.00%) 9750.45 ( 26.72%) Amean fault-huge-32 9981.71 ( 0.00%) 10316.06 ( -3.35%) The average time to fault pages is substantially reduced in the majority of caseds but with the obvious caveat that fewer THPs are actually used in this adverse workload 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 Percentage huge-1 0.71 ( 0.00%) 14.04 (1865.22%) Percentage huge-3 10.77 ( 0.00%) 33.05 (206.85%) Percentage huge-5 60.39 ( 0.00%) 38.51 (-36.23%) Percentage huge-7 45.97 ( 0.00%) 34.57 (-24.79%) Percentage huge-12 68.12 ( 0.00%) 40.07 (-41.17%) Percentage huge-18 64.93 ( 0.00%) 47.82 (-26.35%) Percentage huge-24 62.69 ( 0.00%) 44.23 (-29.44%) Percentage huge-30 43.49 ( 0.00%) 55.38 ( 27.34%) Percentage huge-32 50.72 ( 0.00%) 51.90 ( 2.35%) 4.4.0 4.4.0 kcompactd-v1r1nodefrag-v1r3 Minor Faults 37429143 47564000 Major Faults 1916 1558 Swap Ins 1466 1079 Swap Outs 2936863 149626 Allocation stalls 62510 3 DMA allocs 0 0 DMA32 allocs 6566458 6401314 Normal allocs 216361697 216538171 Movable allocs 0 0 Direct pages scanned 25977580 17998 Kswapd pages scanned 0 3638931 Kswapd pages reclaimed 0 207236 Direct pages reclaimed 8833714 88 Compaction stalls 103349 5 Compaction success 270 4 Compaction failures 103079 1 Note again that while this does swap as it's an aggressive workload, the direct relcim activity and allocation stalls is substantially reduced. There is some kswapd activity but ftrace showed that the kswapd activity was due to normal wakeups from 4K pages being allocated. Compaction-related stalls and activity are almost eliminated. I also tried the stutter benchmark. For this, I do not have figures for NUMA but it's something that does impact UMA so I'll report what is available stutter 4.4.0 4.4.0 kcompactd-v1r1 nodefrag-v1r3 Min mmap 7.3571 ( 0.00%) 7.3438 ( 0.18%) 1st-qrtle mmap 7.5278 ( 0.00%) 17.9200 (-138.05%) 2nd-qrtle mmap 7.6818 ( 0.00%) 21.6055 (-181.25%) 3rd-qrtle mmap 11.0889 ( 0.00%) 21.8881 (-97.39%) Max-90% mmap 27.8978 ( 0.00%) 22.1632 ( 20.56%) Max-93% mmap 28.3202 ( 0.00%) 22.3044 ( 21.24%) Max-95% mmap 28.5600 ( 0.00%) 22.4580 ( 21.37%) Max-99% mmap 29.6032 ( 0.00%) 25.5216 ( 13.79%) Max mmap 4109.7289 ( 0.00%) 4813.9832 (-17.14%) Mean mmap 12.4474 ( 0.00%) 19.3027 (-55.07%) This benchmark is trying to fault an anonymous mapping while there is a heavy IO load -- a scenario that desktop users used to complain about frequently. This shows a mix because the ideal case of mapping with THP is not hit as often. However, note that 99% of the mappings complete 13.79% faster. The CPU usage here is particularly interesting 4.4.0 4.4.0 kcompactd-v1r1nodefrag-v1r3 User 67.50 0.99 System 1327.88 91.30 Elapsed 2079.00 2128.98 And once again we look at the reclaim figures 4.4.0 4.4.0 kcompactd-v1r1nodefrag-v1r3 Minor Faults 335241922 1314582827 Major Faults 715 819 Swap Ins 0 0 Swap Outs 0 0 Allocation stalls 532723 0 DMA allocs 0 0 DMA32 allocs 1822364341 1177950222 Normal allocs 1815640808 1517844854 Movable allocs 0 0 Direct pages scanned 21892772 0 Kswapd pages scanned 20015890 41879484 Kswapd pages reclaimed 19961986 41822072 Direct pages reclaimed 21892741 0 Compaction stalls 1065755 0 Compaction success 514 0 Compaction failures 1065241 0 Allocation stalls and all direct reclaim activity is eliminated as well as compaction-related stalls. THP gives impressive gains in some cases but only if they are quickly available. We're not going to reach the point where they are completely free so lets take the costs out of the fast paths finally and defer the cost to kswapd, kcompactd and khugepaged where it belongs. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@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> |
/linux-master/net/ipv4/ | ||
H A D | tcp_input.c | diff e14cadfd Tue May 09 14:36:56 MDT 2023 Eric Dumazet <edumazet@google.com> tcp: add annotations around sk->sk_shutdown accesses Now sk->sk_shutdown is no longer a bitfield, we can add standard READ_ONCE()/WRITE_ONCE() annotations to silence KCSAN reports like the following: BUG: KCSAN: data-race in tcp_disconnect / tcp_poll write to 0xffff88814588582c of 1 bytes by task 3404 on cpu 1: tcp_disconnect+0x4d6/0xdb0 net/ipv4/tcp.c:3121 __inet_stream_connect+0x5dd/0x6e0 net/ipv4/af_inet.c:715 inet_stream_connect+0x48/0x70 net/ipv4/af_inet.c:727 __sys_connect_file net/socket.c:2001 [inline] __sys_connect+0x19b/0x1b0 net/socket.c:2018 __do_sys_connect net/socket.c:2028 [inline] __se_sys_connect net/socket.c:2025 [inline] __x64_sys_connect+0x41/0x50 net/socket.c:2025 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd read to 0xffff88814588582c of 1 bytes by task 3374 on cpu 0: tcp_poll+0x2e6/0x7d0 net/ipv4/tcp.c:562 sock_poll+0x253/0x270 net/socket.c:1383 vfs_poll include/linux/poll.h:88 [inline] io_poll_check_events io_uring/poll.c:281 [inline] io_poll_task_func+0x15a/0x820 io_uring/poll.c:333 handle_tw_list io_uring/io_uring.c:1184 [inline] tctx_task_work+0x1fe/0x4d0 io_uring/io_uring.c:1246 task_work_run+0x123/0x160 kernel/task_work.c:179 get_signal+0xe64/0xff0 kernel/signal.c:2635 arch_do_signal_or_restart+0x89/0x2a0 arch/x86/kernel/signal.c:306 exit_to_user_mode_loop+0x6f/0xe0 kernel/entry/common.c:168 exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd value changed: 0x03 -> 0x00 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
H A D | tcp.c | diff e14cadfd Tue May 09 14:36:56 MDT 2023 Eric Dumazet <edumazet@google.com> tcp: add annotations around sk->sk_shutdown accesses Now sk->sk_shutdown is no longer a bitfield, we can add standard READ_ONCE()/WRITE_ONCE() annotations to silence KCSAN reports like the following: BUG: KCSAN: data-race in tcp_disconnect / tcp_poll write to 0xffff88814588582c of 1 bytes by task 3404 on cpu 1: tcp_disconnect+0x4d6/0xdb0 net/ipv4/tcp.c:3121 __inet_stream_connect+0x5dd/0x6e0 net/ipv4/af_inet.c:715 inet_stream_connect+0x48/0x70 net/ipv4/af_inet.c:727 __sys_connect_file net/socket.c:2001 [inline] __sys_connect+0x19b/0x1b0 net/socket.c:2018 __do_sys_connect net/socket.c:2028 [inline] __se_sys_connect net/socket.c:2025 [inline] __x64_sys_connect+0x41/0x50 net/socket.c:2025 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd read to 0xffff88814588582c of 1 bytes by task 3374 on cpu 0: tcp_poll+0x2e6/0x7d0 net/ipv4/tcp.c:562 sock_poll+0x253/0x270 net/socket.c:1383 vfs_poll include/linux/poll.h:88 [inline] io_poll_check_events io_uring/poll.c:281 [inline] io_poll_task_func+0x15a/0x820 io_uring/poll.c:333 handle_tw_list io_uring/io_uring.c:1184 [inline] tctx_task_work+0x1fe/0x4d0 io_uring/io_uring.c:1246 task_work_run+0x123/0x160 kernel/task_work.c:179 get_signal+0xe64/0xff0 kernel/signal.c:2635 arch_do_signal_or_restart+0x89/0x2a0 arch/x86/kernel/signal.c:306 exit_to_user_mode_loop+0x6f/0xe0 kernel/entry/common.c:168 exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd value changed: 0x03 -> 0x00 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
/linux-master/kernel/events/ | ||
H A D | core.c | diff 4a1c0f26 Mon Jun 23 08:12:42 MDT 2014 Peter Zijlstra <peterz@infradead.org> perf: Fix lockdep warning on process exit Sasha Levin reported: > While fuzzing with trinity inside a KVM tools guest running the latest -next > kernel I've stumbled on the following spew: > > ====================================================== > [ INFO: possible circular locking dependency detected ] > 3.15.0-next-20140613-sasha-00026-g6dd125d-dirty #654 Not tainted > ------------------------------------------------------- > trinity-c578/9725 is trying to acquire lock: > (&(&pool->lock)->rlock){-.-...}, at: __queue_work (kernel/workqueue.c:1346) > > but task is already holding lock: > (&ctx->lock){-.....}, at: perf_event_exit_task (kernel/events/core.c:7471 kernel/events/core.c:7533) > > which lock already depends on the new lock. > 1 lock held by trinity-c578/9725: > #0: (&ctx->lock){-.....}, at: perf_event_exit_task (kernel/events/core.c:7471 kernel/events/core.c:7533) > > Call Trace: > dump_stack (lib/dump_stack.c:52) > print_circular_bug (kernel/locking/lockdep.c:1216) > __lock_acquire (kernel/locking/lockdep.c:1840 kernel/locking/lockdep.c:1945 kernel/locking/lockdep.c:2131 kernel/locking/lockdep.c:3182) > lock_acquire (./arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602) > _raw_spin_lock (include/linux/spinlock_api_smp.h:143 kernel/locking/spinlock.c:151) > __queue_work (kernel/workqueue.c:1346) > queue_work_on (kernel/workqueue.c:1424) > free_object (lib/debugobjects.c:209) > __debug_check_no_obj_freed (lib/debugobjects.c:715) > debug_check_no_obj_freed (lib/debugobjects.c:727) > kmem_cache_free (mm/slub.c:2683 mm/slub.c:2711) > free_task (kernel/fork.c:221) > __put_task_struct (kernel/fork.c:250) > put_ctx (include/linux/sched.h:1855 kernel/events/core.c:898) > perf_event_exit_task (kernel/events/core.c:907 kernel/events/core.c:7478 kernel/events/core.c:7533) > do_exit (kernel/exit.c:766) > do_group_exit (kernel/exit.c:884) > get_signal_to_deliver (kernel/signal.c:2347) > do_signal (arch/x86/kernel/signal.c:698) > do_notify_resume (arch/x86/kernel/signal.c:751) > int_signal (arch/x86/kernel/entry_64.S:600) Urgh.. so the only way I can make that happen is through: perf_event_exit_task_context() raw_spin_lock(&child_ctx->lock); unclone_ctx(child_ctx) put_ctx(ctx->parent_ctx); raw_spin_unlock_irqrestore(&child_ctx->lock); And we can avoid this by doing the change below. I can't immediately see how this changed recently, but given that you say it's easy to reproduce, lets fix this. Reported-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140623141242.GB19860@laptop.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
/linux-master/tools/perf/ | ||
H A D | builtin-stat.c | diff a9a17902 Mon Jun 01 16:17:36 MDT 2020 Jiri Olsa <jolsa@redhat.com> perf stat: Ensure group is defined on top of the same cpu mask Jin Yao reported the issue (and posted first versions of this change) with groups being defined over events with different cpu mask. This causes assert aborts in get_group_fd, like: # perf stat -M "C2_Pkg_Residency" -a -- sleep 1 perf: util/evsel.c:1464: get_group_fd: Assertion `!(fd == -1)' failed. Aborted All the events in the group have to be defined over the same cpus so the group_fd can be found for every leader/member pair. Adding check to ensure this condition is met and removing the group (with warning) if we detect mixed cpus, like: $ sudo perf stat -e '{power/energy-cores/,cycles},{instructions,power/energy-cores/}' WARNING: event cpu maps do not match, disabling group: anon group { power/energy-cores/, cycles } anon group { instructions, power/energy-cores/ } Ian asked also for cpu maps details, it's displayed in verbose mode: $ sudo perf stat -e '{cycles,power/energy-cores/}' -v WARNING: group events cpu maps do not match, disabling group: anon group { power/energy-cores/, cycles } power/energy-cores/: 0 cycles: 0-7 anon group { instructions, power/energy-cores/ } instructions: 0-7 power/energy-cores/: 0 Committer testing: [root@seventh ~]# perf stat -e '{power/energy-cores/,cycles},{instructions,power/energy-cores/}' WARNING: grouped events cpus do not match, disabling group: anon group { power/energy-cores/, cycles } anon group { instructions, power/energy-cores/ } ^C Performance counter stats for 'system wide': 12.62 Joules power/energy-cores/ 106,920,637 cycles 80,228,899 instructions # 0.75 insn per cycle 12.62 Joules power/energy-cores/ 14.514476987 seconds time elapsed [root@seventh ~]# But if we put compatible events in each group it works: [root@seventh ~]# perf stat -e '{power/energy-cores/,power/energy-ram/},{instructions,cycles}' -a sleep 2 Performance counter stats for 'system wide': 1.95 Joules power/energy-cores/ 0.92 Joules power/energy-ram/ 29,305,715 instructions # 1.03 insn per cycle 28,423,338 cycles 2.001438142 seconds time elapsed [root@seventh ~]# This needs improvement tho: [root@seventh ~]# perf stat -e '{power/energy-cores/,power/energy-ram/},{instructions,cycles}' sleep 2 Error: The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (power/energy-cores/). /bin/dmesg | grep -i perf may provide additional information. [root@seventh ~]# We need to emit a better message, one stating that the power/ events can't be used for a specific workload, instead it is per-cpu or system wide. Fixes: 6a4bb04caacc8 ("perf tools: Enable grouping logic for parsed events") Co-developed-by: Jin Yao <yao.jin@linux.intel.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Ian Rogers <irogers@google.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/20200602101736.GE1112120@krava Signed-off-by: Jin Yao <yao.jin@linux.intel.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
/linux-master/include/linux/ | ||
H A D | mm.h | diff 715cbfd6 Fri May 07 13:05:06 MDT 2021 Matthew Wilcox (Oracle) <willy@infradead.org> mm/migrate: Add folio_migrate_copy() This is the folio equivalent of migrate_page_copy(), which is retained as a wrapper for filesystems which are not yet converted to folios. Also convert copy_huge_page() to folio_copy(). Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> |
/linux-master/ | ||
H A D | MAINTAINERS | diff 715ecbc1 Mon Nov 08 09:27:06 MST 2021 Luca Ceresoli <luca@lucaceresoli.net> power: supply: max77976: add Maxim MAX77976 charger driver Add support for the MAX77976 3.5/5.5A 1-Cell Li+ Battery Charger. This is a simple implementation enough to be used as a simple battery charger without OTG and boost. Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com> |
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