mm/damon/core-test: test max_nr_accesses overflow caused divide-by-zero

Commit 35f5d94187a6 ("mm/damon: implement a function for max nr_accesses
safe calculation") has fixed an overflow bug that could cause
divide-by-zero. Add a kunit test for the bug to ensure similar bugs are
not introduced again.

Link: https://lkml.kernel.org/r/20231213190338.54146-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon: update email of SeongJae

Patch series "mm/damon: misc updates for 6.8".

Update comments, tests, and documents for DAMON.


This patch (of 6):

SeongJae is using his kernel.org account for DAMON development. Update
the old email addresses on the comments of DAMON source files.

Link: https://lkml.kernel.org/r/20231213190338.54146-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20231213190338.54146-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core-test: add a unit test for the feedback loop algorithm

Implement a simple kunit test for testing the behavior of the feedback
loop algorithm for the aim-oriented feedback-friven DAMOS aggressiveness
auto tuning.

Link: https://lkml.kernel.org/r/20231130023652.50284-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core-test: test damon_split_region_at()'s access rate copying

damon_split_region_at() should set access rate related fields of the
resulting regions same. It may forgotten, and actually there was the
mistake before. Test it with the unit test case for the function.

Link: https://lkml.kernel.org/r/20231119171529.66863-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core-test: fix memory leak in damon_new_ctx()

When CONFIG_DAMON_KUNIT_TEST=y and making CONFIG_DEBUG_KMEMLEAK=y and
CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN=y, the below memory leak is detected.

The damon_ctx which is allocated by kzalloc() in damon_new_ctx() in
damon_test_ops_registration() and damon_test_set_attrs() are not freed.
So use damon_destroy_ctx() to free it. After applying this patch, the
following memory leak is never detected

unreferenced object 0xffff2b49c6968800 (size 512):
comm "kunit_try_catch", pid 350, jiffies 4294895294 (age 557.028s)
hex dump (first 32 bytes):
88 13 00 00 00 00 00 00 a0 86 01 00 00 00 00 00 ................
00 87 93 03 00 00 00 00 0a 00 00 00 00 00 00 00 ................
backtrace:
[<0000000088e71769>] slab_post_alloc_hook+0xb8/0x368
[<0000000073acab3b>] __kmem_cache_alloc_node+0x174/0x290
[<00000000b5f89cef>] kmalloc_trace+0x40/0x164
[<00000000eb19e83f>] damon_new_ctx+0x28/0xb4
[<00000000daf6227b>] damon_test_ops_registration+0x34/0x328
[<00000000559c4801>] kunit_try_run_case+0x50/0xac
[<000000003932ed49>] kunit_generic_run_threadfn_adapter+0x20/0x2c
[<000000003c3e9211>] kthread+0x124/0x130
[<0000000028f85bdd>] ret_from_fork+0x10/0x20
unreferenced object 0xffff2b49c1a9cc00 (size 512):
comm "kunit_try_catch", pid 356, jiffies 4294895306 (age 557.000s)
hex dump (first 32 bytes):
88 13 00 00 00 00 00 00 a0 86 01 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 0a 00 00 00 00 00 00 00 ................
backtrace:
[<0000000088e71769>] slab_post_alloc_hook+0xb8/0x368
[<0000000073acab3b>] __kmem_cache_alloc_node+0x174/0x290
[<00000000b5f89cef>] kmalloc_trace+0x40/0x164
[<00000000eb19e83f>] damon_new_ctx+0x28/0xb4
[<00000000058495c4>] damon_test_set_attrs+0x30/0x1a8
[<00000000559c4801>] kunit_try_run_case+0x50/0xac
[<000000003932ed49>] kunit_generic_run_threadfn_adapter+0x20/0x2c
[<000000003c3e9211>] kthread+0x124/0x130
[<0000000028f85bdd>] ret_from_fork+0x10/0x20

Link: https://lkml.kernel.org/r/20230918120951.2230468-3-ruanjinjie@huawei.com
Fixes: d1836a3b2a9a ("mm/damon/core-test: initialise context before test in damon_test_set_attrs()")
Fixes: 4f540f5ab4f2 ("mm/damon/core-test: add a kunit test case for ops registration")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Feng Tang <feng.tang@intel.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core-test: fix memory leak in damon_new_region()

Patch series "mm/damon/core-test: Fix memory leaks in core-test", v3.

There are a few memory leaks in core-test which are detected by kmemleak.
This patchset fixes the issues.


This patch (of 2):

When CONFIG_DAMON_KUNIT_TEST=y and making CONFIG_DEBUG_KMEMLEAK=y
and CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN=y, the below memory leak is detected.

The damon_region which is allocated by kmem_cache_alloc() in
damon_new_region() in damon_test_regions() and
damon_test_update_monitoring_result() are not freed.

So for damon_test_regions(), replace damon_del_region() call with
damon_destroy_region() so that it calls both damon_del_region() and
damon_free_region(), the latter will free the damon_region. For
damon_test_update_monitoring_result(), call damon_free_region() to
free it. After applying this patch, the following memory leak is never
detected.

unreferenced object 0xffff2b49c3edc000 (size 56):
comm "kunit_try_catch", pid 338, jiffies 4294895280 (age 557.084s)
hex dump (first 32 bytes):
01 00 00 00 00 00 00 00 02 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 49 2b ff ff ............I+..
backtrace:
[<0000000088e71769>] slab_post_alloc_hook+0xb8/0x368
[<00000000b528f67c>] kmem_cache_alloc+0x168/0x284
[<000000008603f022>] damon_new_region+0x28/0x54
[<00000000a3b8c64e>] damon_test_regions+0x38/0x270
[<00000000559c4801>] kunit_try_run_case+0x50/0xac
[<000000003932ed49>] kunit_generic_run_threadfn_adapter+0x20/0x2c
[<000000003c3e9211>] kthread+0x124/0x130
[<0000000028f85bdd>] ret_from_fork+0x10/0x20
unreferenced object 0xffff2b49c5b20000 (size 56):
comm "kunit_try_catch", pid 354, jiffies 4294895304 (age 556.988s)
hex dump (first 32 bytes):
03 00 00 00 00 00 00 00 07 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 96 00 00 00 49 2b ff ff ............I+..
backtrace:
[<0000000088e71769>] slab_post_alloc_hook+0xb8/0x368
[<00000000b528f67c>] kmem_cache_alloc+0x168/0x284
[<000000008603f022>] damon_new_region+0x28/0x54
[<00000000ca019f80>] damon_test_update_monitoring_result+0x18/0x34
[<00000000559c4801>] kunit_try_run_case+0x50/0xac
[<000000003932ed49>] kunit_generic_run_threadfn_adapter+0x20/0x2c
[<000000003c3e9211>] kthread+0x124/0x130
[<0000000028f85bdd>] ret_from_fork+0x10/0x20

Link: https://lkml.kernel.org/r/20230918120951.2230468-1-ruanjinjie@huawei.com
Link: https://lkml.kernel.org/r/20230918120951.2230468-2-ruanjinjie@huawei.com
Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests")
Fixes: f4c978b6594b ("mm/damon/core-test: add a test for damon_update_monitoring_results()")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: Feng Tang <feng.tang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core: introduce nr_accesses_bp

Add yet another representation of the access rate of each region, namely
nr_accesses_bp. It is just same to the nr_accesses but represents the
value in basis point (1 in 10,000), and updated at once in every
aggregation interval. That is, moving_accesses_bp is just nr_accesses *
10000. This may seems useless at the moment. However, it will be useful
for representing less than one nr_accesses value that will be needed to
make moving sum-based nr_accesses.

Link: https://lkml.kernel.org/r/20230915025251.72816-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core-test: add a unit test for damon_moving_sum()

Add a simple unit test for the pseudo moving-sum function
(damon_moving_sum()).

Link: https://lkml.kernel.org/r/20230915025251.72816-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core-test: add a unit test for __damos_filter_out()

Implement a kunit test for the core of address range DAMOS filter
handling, namely __damos_filter_out(). The test especially focus on
regions that overlap with given filter's target address range.

Link: https://lkml.kernel.org/r/20230802214312.110532-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core-test: add a test for damos_new_filter()

damos_new_filter() was having a bug that not initializing ->list field of
the returning damos_filter struct, which results in access to
uninitialized memory. Add a unit test for the function.

Link: https://lkml.kernel.org/r/20230729203733.38949-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core-test: initialise context before test in damon_test_set_attrs()

Running kunit test for 6.5-rc1 hits one bug:

ok 10 damon_test_update_monitoring_result
general protection fault, probably for non-canonical address 0x1bffa5c419cfb81: 0000 [#1] PREEMPT SMP NOPTI
CPU: 1 PID: 110 Comm: kunit_try_catch Tainted: G N 6.5.0-rc2 #15
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
RIP: 0010:damon_set_attrs+0xb9/0x120
Code: f8 00 00 00 4c 8d 58 e0 48 39 c3 74 ba 41 ba 59 17 b7 d1 49 8b 43 10 4d
8d 4b 10 48 8d 70 e0 49 39 c1 74 50 49 8b 40 08 31 d2 <69> 4e 18 10 27 00 00
49 f7 30 31 d2 48 89 c5 89 c8 f7 f5 31 d2 89
RSP: 0000:ffffc900005bfd40 EFLAGS: 00010246
RAX: ffffffff81159fc0 RBX: ffffc900005bfeb8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 01bffa5c419cfb69 RDI: ffffc900005bfd70
RBP: ffffc90000013c10 R08: ffffc900005bfdc0 R09: ffffffff81ff10ed
R10: 00000000d1b71759 R11: ffffffff81ff10dd R12: ffffc90000013a78
R13: ffff88810eb78180 R14: ffffffff818297c0 R15: ffffc90000013c28
FS: 0000000000000000(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000002a1c001 CR4: 0000000000370ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
damon_test_set_attrs+0x63/0x1f0
kunit_generic_run_threadfn_adapter+0x17/0x30
kthread+0xfd/0x130

The problem seems to be related with the damon_ctx was used without
being initialized. Fix it by adding the initialization.

Link: https://lkml.kernel.org/r/20230718052811.1065173-1-feng.tang@intel.com
Fixes: aa13779be6b7 ("mm/damon/core-test: add a test for damon_set_attrs()")
Signed-off-by: Feng Tang <feng.tang@intel.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core-test: add a test for damon_set_attrs()

Commit 5ff6e2fff88e ("mm/damon/core: fix divide error in
damon_nr_accesses_to_accesses_bp()") fixed a bug by adding arguments
validation in damon_set_attrs(). Add a unit test for the added validation
to ensure the bug cannot occur again.

Link: https://lkml.kernel.org/r/20230615183323.87561-1-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core-test: add a test for damon_update_monitoring_results()

Add a simple unit test for damon_update_monitoring_results() function.

Link: https://lkml.kernel.org/r/20230119013831.1911-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core-test: test damon_set_regions

Preceding commit fixes a bug in 'damon_set_regions()', which allows holes
in the new monitoring target ranges. This commit adds a kunit test case
for the problem to avoid any regression.

Link: https://lkml.kernel.org/r/20220909202901.57977-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yun Levi <ppbuk5246@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core: simplify the parameter passing for region split operation

The parameter 'struct damon_ctx *ctx' is unnecessary in damon region split
operation, so we can remove it.

Link: https://lkml.kernel.org/r/1660403943-29124-1-git-send-email-kaixuxia@tencent.com
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core-test: add a kunit test case for ops registration

This commit adds a simple kunit test case for DAMON operations
registration feature.

Link: https://lkml.kernel.org/r/20220419122225.290518-1-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon: remove the target id concept

DAMON asks each monitoring target ('struct damon_target') to have one
'unsigned long' integer called 'id', which should be unique among the
targets of same monitoring context. Meaning of it is, however, totally up
to the monitoring primitives that registered to the monitoring context.
For example, the virtual address spaces monitoring primitives treats the
id as a 'struct pid' pointer.

This makes the code flexible, but ugly, not well-documented, and
type-unsafe[1]. Also, identification of each target can be done via its
index. For the reason, this commit removes the concept and uses clear
type definition. For now, only 'struct pid' pointer is used for the
virtual address spaces monitoring. If DAMON is extended in future so that
we need to put another identifier field in the struct, we will use a union
for such primitives-dependent fields and document which primitives are
using which type.

[1] https://lore.kernel.org/linux-mm/20211013154535.4aaeaaf9d0182922e405dd1e@linux-foundation.org/

Link: https://lkml.kernel.org/r/20211230100723.2238-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/damon/core: move damon_set_targets() into dbgfs

damon_set_targets() function is defined in the core for general use cases,
but called from only dbgfs. Also, because the function is for general use
cases, dbgfs does additional handling of pid type target id case. To make
the situation simpler, this commit moves the function into dbgfs and makes
it to do the pid type case handling on its own.

Link: https://lkml.kernel.org/r/20211230100723.2238-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/damon/core-test: fix wrong expectations for 'damon_split_regions_of()'

Kunit test cases for 'damon_split_regions_of()' expects the number of
regions after calling the function will be same to their request
('nr_sub'). However, the requested number is just an upper-limit,
because the function randomly decides the size of each sub-region.

This fixes the wrong expectation.

Link: https://lkml.kernel.org/r/20211028090628.14948-1-sj@kernel.org
Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/damon: add kunit tests

This commit adds kunit based unit tests for the core and the virtual
address spaces monitoring primitives of DAMON.

Link: https://lkml.kernel.org/r/20210716081449.22187-12-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Fernand Sieber <sieberf@amazon.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
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>