Patch series "mm/damon: cleanup and refactoring code", v2.
This patchset cleans up and refactors a range of DAMON code including the
core, DAMON sysfs interface, and DAMON modules, for better readability and
convenient future feature implementations.
In detail, this patchset splits unnecessarily long and complex functions
in core into smaller functions (patches 1-4). Then, it cleans up the
DAMON sysfs interface by using more type-safe code (patch 5) and removing
unnecessary function parameters (patch 6). Further, it refactor the code
by distributing the code into multiple files (patches 7-10). Last two
patches (patches 11 and 12) deduplicates and remove unnecessary header
inclusion in DAMON modules (reclaim and lru_sort).
This patch (of 12):
The DAMOS action applying function, 'damon_do_apply_schemes()', is quite
long and not so simple. Split out the already quota-charged region skip
code, which is not a small amount of simple code, into a new function with
some comments for better readability.
Link: https://lkml.kernel.org/r/20221026225943.100429-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20221026225943.100429-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit da87878010 ("mm/damon/sysfs: support online inputs update") made
'damon_sysfs_set_schemes()' to be called for running DAMON context, which
could have schemes. In the case, DAMON sysfs interface is supposed to
update, remove, or add schemes to reflect the sysfs files. However, the
code is assuming the DAMON context wouldn't have schemes at all, and
therefore creates and adds new schemes. As a result, the code doesn't
work as intended for online schemes tuning and could have more than
expected memory footprint. The schemes are all in the DAMON context, so
it doesn't leak the memory, though.
Remove the wrong asssumption (the DAMON context wouldn't have schemes) in
'damon_sysfs_set_schemes()' to fix the bug.
Link: https://lkml.kernel.org/r/20221122194831.3472-1-sj@kernel.org
Fixes: da87878010 ("mm/damon/sysfs: support online inputs update")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [5.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
A DAMON sysfs interface user can start DAMON with a scheme, remove the
sysfs directory for the scheme, and then ask update of the scheme's stats.
Because the schemes stats update logic isn't aware of the situation, it
results in an invalid memory access. Fix the bug by checking if the
scheme sysfs directory exists.
Link: https://lkml.kernel.org/r/20221114175552.1951-1-sj@kernel.org
Fixes: 0ac32b8aff ("mm/damon/sysfs: support DAMOS stats")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [v5.18]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
A user could write a name of a file under 'damon/' debugfs directory,
which is not a user-created context, to 'rm_contexts' file. In the case,
'dbgfs_rm_context()' just assumes it's the valid DAMON context directory
only if a file of the name exist. As a result, invalid memory access
could happen as below. Fix the bug by checking if the given input is for
a directory. This check can filter out non-context inputs because
directories under 'damon/' debugfs directory can be created via only
'mk_contexts' file.
This bug has found by syzbot[1].
[1] https://lore.kernel.org/damon/000000000000ede3ac05ec4abf8e@google.com/
Link: https://lkml.kernel.org/r/20221107165001.5717-2-sj@kernel.org
Fixes: 75c1c2b53c ("mm/damon/dbgfs: support multiple contexts")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: syzbot+6087eafb76a94c4ac9eb@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org> [5.15.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
refcounting errors in ZONE_DEVICE pages.
- Peter Xu fixes some userfaultfd test harness instability.
- Various other patches in MM, mainly fixes.
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Merge tag 'mm-stable-2022-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull more MM updates from Andrew Morton:
- fix a race which causes page refcounting errors in ZONE_DEVICE pages
(Alistair Popple)
- fix userfaultfd test harness instability (Peter Xu)
- various other patches in MM, mainly fixes
* tag 'mm-stable-2022-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (29 commits)
highmem: fix kmap_to_page() for kmap_local_page() addresses
mm/page_alloc: fix incorrect PGFREE and PGALLOC for high-order page
mm/selftest: uffd: explain the write missing fault check
mm/hugetlb: use hugetlb_pte_stable in migration race check
mm/hugetlb: fix race condition of uffd missing/minor handling
zram: always expose rw_page
LoongArch: update local TLB if PTE entry exists
mm: use update_mmu_tlb() on the second thread
kasan: fix array-bounds warnings in tests
hmm-tests: add test for migrate_device_range()
nouveau/dmem: evict device private memory during release
nouveau/dmem: refactor nouveau_dmem_fault_copy_one()
mm/migrate_device.c: add migrate_device_range()
mm/migrate_device.c: refactor migrate_vma and migrate_deivce_coherent_page()
mm/memremap.c: take a pgmap reference on page allocation
mm: free device private pages have zero refcount
mm/memory.c: fix race when faulting a device private page
mm/damon: use damon_sz_region() in appropriate place
mm/damon: move sz_damon_region to damon_sz_region
lib/test_meminit: add checks for the allocation functions
...
In many places we can use damon_sz_region() to instead of "r->ar.end -
r->ar.start".
Link: https://lkml.kernel.org/r/20220927001946.85375-2-xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Rename sz_damon_region() to damon_sz_region(), and move it to
"include/linux/damon.h", because in many places, we can to use this func.
Link: https://lkml.kernel.org/r/20220927001946.85375-1-xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
not.
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Merge tag 'mm-hotfixes-stable-2022-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc hotfixes from Andrew Morton:
"Five hotfixes - three for nilfs2, two for MM. For are cc:stable, one
is not"
* tag 'mm-hotfixes-stable-2022-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
nilfs2: fix leak of nilfs_root in case of writer thread creation failure
nilfs2: fix NULL pointer dereference at nilfs_bmap_lookup_at_level()
nilfs2: fix use-after-free bug of struct nilfs_root
mm/damon/core: initialize damon_target->list in damon_new_target()
mm/hugetlb: fix races when looking up a CONT-PTE/PMD size hugetlb page
'struct damon_target' creation function, 'damon_new_target()' is not
initializing its '->list' field, unlike other DAMON structs creator
functions such as 'damon_new_region()'. Normal users of
'damon_new_target()' initializes the field by adding the target to DAMON
context's targets list, but some code could access the uninitialized
field.
This commit avoids the case by initializing the field in
'damon_new_target()'.
Link: https://lkml.kernel.org/r/20221002193130.8227-1-sj@kernel.org
Fixes: f23b8eee18 ("mm/damon/core: implement region-based sampling")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
linux-next for a couple of months without, to my knowledge, any negative
reports (or any positive ones, come to that).
- Also the Maple Tree from Liam R. Howlett. An overlapping range-based
tree for vmas. It it apparently slight more efficient in its own right,
but is mainly targeted at enabling work to reduce mmap_lock contention.
Liam has identified a number of other tree users in the kernel which
could be beneficially onverted to mapletrees.
Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
(https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com).
This has yet to be addressed due to Liam's unfortunately timed
vacation. He is now back and we'll get this fixed up.
- Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
clang-generated instrumentation to detect used-unintialized bugs down to
the single bit level.
KMSAN keeps finding bugs. New ones, as well as the legacy ones.
- Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
memory into THPs.
- Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support
file/shmem-backed pages.
- userfaultfd updates from Axel Rasmussen
- zsmalloc cleanups from Alexey Romanov
- cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure
- Huang Ying adds enhancements to NUMA balancing memory tiering mode's
page promotion, with a new way of detecting hot pages.
- memcg updates from Shakeel Butt: charging optimizations and reduced
memory consumption.
- memcg cleanups from Kairui Song.
- memcg fixes and cleanups from Johannes Weiner.
- Vishal Moola provides more folio conversions
- Zhang Yi removed ll_rw_block() :(
- migration enhancements from Peter Xu
- migration error-path bugfixes from Huang Ying
- Aneesh Kumar added ability for a device driver to alter the memory
tiering promotion paths. For optimizations by PMEM drivers, DRM
drivers, etc.
- vma merging improvements from Jakub Matěn.
- NUMA hinting cleanups from David Hildenbrand.
- xu xin added aditional userspace visibility into KSM merging activity.
- THP & KSM code consolidation from Qi Zheng.
- more folio work from Matthew Wilcox.
- KASAN updates from Andrey Konovalov.
- DAMON cleanups from Kaixu Xia.
- DAMON work from SeongJae Park: fixes, cleanups.
- hugetlb sysfs cleanups from Muchun Song.
- Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
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Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
linux-next for a couple of months without, to my knowledge, any
negative reports (or any positive ones, come to that).
- Also the Maple Tree from Liam Howlett. An overlapping range-based
tree for vmas. It it apparently slightly more efficient in its own
right, but is mainly targeted at enabling work to reduce mmap_lock
contention.
Liam has identified a number of other tree users in the kernel which
could be beneficially onverted to mapletrees.
Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
at [1]. This has yet to be addressed due to Liam's unfortunately
timed vacation. He is now back and we'll get this fixed up.
- Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
clang-generated instrumentation to detect used-unintialized bugs down
to the single bit level.
KMSAN keeps finding bugs. New ones, as well as the legacy ones.
- Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
memory into THPs.
- Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to
support file/shmem-backed pages.
- userfaultfd updates from Axel Rasmussen
- zsmalloc cleanups from Alexey Romanov
- cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and
memory-failure
- Huang Ying adds enhancements to NUMA balancing memory tiering mode's
page promotion, with a new way of detecting hot pages.
- memcg updates from Shakeel Butt: charging optimizations and reduced
memory consumption.
- memcg cleanups from Kairui Song.
- memcg fixes and cleanups from Johannes Weiner.
- Vishal Moola provides more folio conversions
- Zhang Yi removed ll_rw_block() :(
- migration enhancements from Peter Xu
- migration error-path bugfixes from Huang Ying
- Aneesh Kumar added ability for a device driver to alter the memory
tiering promotion paths. For optimizations by PMEM drivers, DRM
drivers, etc.
- vma merging improvements from Jakub Matěn.
- NUMA hinting cleanups from David Hildenbrand.
- xu xin added aditional userspace visibility into KSM merging
activity.
- THP & KSM code consolidation from Qi Zheng.
- more folio work from Matthew Wilcox.
- KASAN updates from Andrey Konovalov.
- DAMON cleanups from Kaixu Xia.
- DAMON work from SeongJae Park: fixes, cleanups.
- hugetlb sysfs cleanups from Muchun Song.
- Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1]
* tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits)
hugetlb: allocate vma lock for all sharable vmas
hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
hugetlb: fix vma lock handling during split vma and range unmapping
mglru: mm/vmscan.c: fix imprecise comments
mm/mglru: don't sync disk for each aging cycle
mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol
mm: memcontrol: use do_memsw_account() in a few more places
mm: memcontrol: deprecate swapaccounting=0 mode
mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled
mm/secretmem: remove reduntant return value
mm/hugetlb: add available_huge_pages() func
mm: remove unused inline functions from include/linux/mm_inline.h
selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory
selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd
selftests/vm: add thp collapse shmem testing
selftests/vm: add thp collapse file and tmpfs testing
selftests/vm: modularize thp collapse memory operations
selftests/vm: dedup THP helpers
mm/khugepaged: add tracepoint to hpage_collapse_scan_file()
mm/madvise: add file and shmem support to MADV_COLLAPSE
...
The bodies of damon_{reclaim,lru_sort}_apply_parameters() contain
duplicates. This commit adds a common function
damon_set_region_biggest_system_ram_default() to remove the duplicates.
Link: https://lkml.kernel.org/r/6329f00d.a70a0220.9bb29.3678SMTPIN_ADDED_BROKEN@mx.google.com
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We had better return the 'err' value when calling kstrtoul() failed, so
the user will know why it really fails, there do little change, let it
return the 'err' value when failed.
Link: https://lkml.kernel.org/r/6329ebe0.050a0220.ec4bd.297cSMTPIN_ADDED_BROKEN@mx.google.com
Suggested-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Xin Hao <xhao@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In the beginning there is only one damos_action 'DAMOS_PAGEOUT' that need
to get the coldness score of a region for a scheme, which using
damon_pageout_score() to do that. But now there are also other
damos_action actions need the coldness score, so rename it to
damon_cold_score() to make more sense.
Link: https://lkml.kernel.org/r/1663423014-28907-1-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>
There is no point in returning an int from damon_set_schemes(). It always
returns 0 which is meaningless for the caller, so change it to return void
directly.
Link: https://lkml.kernel.org/r/1663341635-12675-1-git-send-email-kaixuxia@tencent.com
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_lru_sort_wmarks is only used in lru_sort.c now, change it to static.
Link: https://lkml.kernel.org/r/20220915021024.4177940-2-yangyingliang@huawei.com
Fixes: 189aa3d58206 ("mm/damon/lru_sort: use watermarks parameters generator macro")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_reclaim_wmarks is only used in reclaim.c now, change it to static.
Link: https://lkml.kernel.org/r/20220915021024.4177940-1-yangyingliang@huawei.com
Fixes: 89dd02d8abd1 ("mm/damon/reclaim: use watermarks parameters generator macro")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We could use 'struct damon_target *' directly instead of 'void *' in
target_valid() operation to make code simple.
Link: https://lkml.kernel.org/r/1663241621-13293-1-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>
In damon_lru_sort_new_hot_scheme() and damon_lru_sort_new_cold_scheme(),
they have so much in common, so we can combine them into a single
function, and we just need to distinguish their differences.
[yangyingliang@huawei.com: change damon_lru_sort_stub_pattern to static]
Link: https://lkml.kernel.org/r/20220917121228.1889699-1-yangyingliang@huawei.com
Link: https://lkml.kernel.org/r/20220915133041.71819-1-sj@kernel.org
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Xin Hao <xhao@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In damon_sysfs_destroy_targets(), we call damon_target_has_pid() to check
whether the 'ctx' include a valid pid, but there no need to call
damon_target_has_pid() to check repeatedly, just need call it once.
[xhao@linux.alibaba.com: more simplified code calls damon_target_has_pid()]
Link: https://lkml.kernel.org/r/20220916133535.7428-1-xhao@linux.alibaba.com
Link: https://lkml.kernel.org/r/20220915142237.92529-1-xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When the 'kdamond_wait_activation()' function or 'after_sampling()' or
'after_aggregation()' DAMON callbacks return an error, it is unnecessary
to use bool 'done' to check if kdamond should be finished. This commit
simplifies the kdamond stop mechanism by removing 'done' and break the
while loop directly in the cases.
Link: https://lkml.kernel.org/r/1663060287-30201-4-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>
We can initialize the variable 'pid' with '-1' in pid_show() to simplify
the variable assignment operation and make the code more readable.
Link: https://lkml.kernel.org/r/1663060287-30201-3-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>
damon_lru_sort_new_{hot,cold}_scheme() have quite a lot of duplicates.
This commit factors out the duplicate to a separate function and use it
for reducing the duplicate.
Link: https://lkml.kernel.org/r/20220913174449.50645-23-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit makes DAMON_LRU_SORT to generate the module parameters for
DAMOS watermarks using the generator macro to simplify the code and reduce
duplicates.
Link: https://lkml.kernel.org/r/20220913174449.50645-22-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit makes DAMON_RECLAIM to generate the module parameters for
DAMOS quotas using the generator macro to simplify the code and reduce
duplicates.
Link: https://lkml.kernel.org/r/20220913174449.50645-21-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_LRU_SORT have module parameters for DAMOS time quota only but size
quota. This commit implements a macro for generating the module
parameters so that we can reuse later.
Link: https://lkml.kernel.org/r/20220913174449.50645-20-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_RECLAIM and DAMON_LRU_SORT have module parameters for DAMOS quotas
that having same names. This commit implements a macro for generating
such module parameters so that we can reuse later.
Link: https://lkml.kernel.org/r/20220913174449.50645-19-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit makes DAMON_LRU_SORT to generate the module parameters for
DAMOS statistics using the generator macro to simplify the code and reduce
duplicates.
Link: https://lkml.kernel.org/r/20220913174449.50645-18-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit makes DAMON_RECLAIM to generate the module parameters for
DAMOS statistics using the generator macro to simplify the code and
reduce duplicates.
Link: https://lkml.kernel.org/r/20220913174449.50645-17-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_RECLAIM and DAMON_LRU_SORT have module parameters for DAMOS
statistics that having same names. This commit implements a macro for
generating such module parameters so that we can reuse later.
Link: https://lkml.kernel.org/r/20220913174449.50645-16-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit makes DAMON_RECLAIM to generate the module parameters for
DAMOS watermarks using the generator macro to simplify the code and reduce
duplicates.
Link: https://lkml.kernel.org/r/20220913174449.50645-15-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit makes DAMON_LRU_SORT to generate the module parameters for
DAMOS watermarks using the generator macro to simplify the code and reduce
duplicates.
Link: https://lkml.kernel.org/r/20220913174449.50645-14-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_RECLAIM and DAMON_LRU_SORT have module parameters for watermarks
that having same names. This commit implements a macro for generating
such module parameters so that we can reuse later.
Link: https://lkml.kernel.org/r/20220913174449.50645-13-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit makes DAMON_RECLAIM to generate the module parameters for
DAMON monitoring attributes using the generator macro to simplify the code
and reduce duplicates.
Link: https://lkml.kernel.org/r/20220913174449.50645-12-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit makes DAMON_LRU_SORT to generate the module parameters for
DAMON monitoring attributes using the generator macro to simplify the code
and reduce duplicates.
Link: https://lkml.kernel.org/r/20220913174449.50645-11-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_RECLAIM and DAMON_LRU_SORT have module parameters for monitoring
attributes that having same names. This commot implements a macro for
generating such module parameters so that we can reuse later.
Link: https://lkml.kernel.org/r/20220913174449.50645-10-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_LRU_SORT receives monitoring attributes by parameters one by one to
separate variables, and then combines those into 'struct damon_attrs'.
This commit makes the module directly stores the parameter values to a
static 'struct damon_attrs' variable and use it to simplify the code.
Link: https://lkml.kernel.org/r/20220913174449.50645-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_RECLAIM receives monitoring attributes by parameters one by one to
separate variables, and then combine those into 'struct damon_attrs'.
This commit makes the module directly stores the parameter values to a
static 'struct damon_attrs' variable and use it to simplify the code.
Link: https://lkml.kernel.org/r/20220913174449.50645-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Number of parameters for 'damon_set_attrs()' is six. As it could be
confusing and verbose, this commit reduces the number by receiving single
pointer to a 'struct damon_attrs'.
Link: https://lkml.kernel.org/r/20220913174449.50645-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON monitoring attributes are directly defined as fields of 'struct
damon_ctx'. This makes 'struct damon_ctx' a little long and complicated.
This commit defines and uses a struct, 'struct damon_attrs', which is
dedicated for only the monitoring attributes to make the purpose of the
five values clearer and simplify 'struct damon_ctx'.
Link: https://lkml.kernel.org/r/20220913174449.50645-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The 'struct damos' creation function, 'damon_new_scheme()', does
initialization of private fileds of 'struct damos_quota' in it. As its
verbose and makes the function unnecessarily long, this commit factors it
out to separate function.
Link: https://lkml.kernel.org/r/20220913174449.50645-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The function for new 'struct damos' creation, 'damon_new_scheme()', copies
each field of the struct one by one, though it could simply copied via
struct to struct. This commit replaces the unnecessarily verbose
field-to-field copies with struct-to-struct copies to make code simple and
short.
Link: https://lkml.kernel.org/r/20220913174449.50645-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The bodies of damon_pa_{mark_accessed,deactivate_pages}() contains
duplicates. This commit factors out the common part to a separate
function and removes the duplicates.
Link: https://lkml.kernel.org/r/20220913174449.50645-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/damon: cleanup code".
DAMON code was not so clean from the beginning, but it has been too much
nowadays, especially due to the duplicates in DAMON_RECLAIM and
DAMON_LRU_SORT. This patchset cleans some of the mess.
This patch (of 22):
The 'switch-case' statement in 'damon_va_apply_scheme()' function provides
a 'case' for every supported DAMOS action while all not-yet-supported
DAMOS actions fall through the 'default' case, and comment it so that
people can easily know which actions are supported. Its counterpart in
'paddr', 'damon_pa_apply_scheme()', however, doesn't. This commit makes
the 'paddr' side function follows the pattern of 'vaddr' for better
readability and consistency.
Link: https://lkml.kernel.org/r/20220913174449.50645-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20220913174449.50645-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In damon_lru_sort_apply_parameters(), we can use damon_set_schemes() to
replace the way of creating the first 'scheme' in original code, this
makes the code look cleaner.
Link: https://lkml.kernel.org/r/20220911005917.835-1-xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kdamond is implemented as a periodical split-merge pattern, which will
create and destroy regions possibly at high frequency (hundreds or even
thousands of per sec), depending on the number of regions and aggregation
period. In that case, kmalloc and kfree could bring speed and space
overheads, which can be improved by using a private kmem cache.
[set_pte_at@outlook.com: creating kmem cache for damon regions by KMEM_CACHE()]
Link: https://lkml.kernel.org/r/Message-ID:
Link: https://lkml.kernel.org/r/TYCP286MB2323DA1894FA55BB9CF90978CA449@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COM
Signed-off-by: Dawei Li <set_pte_at@outlook.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We can use the 'damon_sysfs_kdamond_running()' wrapper directly to check
if the kdamond is running in 'damon_sysfs_turn_damon_on()'.
Link: https://lkml.kernel.org/r/1662995513-24489-1-git-send-email-kaixuxia@tencent.com
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There's no need to run container_of() as early as we do.
The compiler figures this out, but the resulting code is more readable.
Link: https://lkml.kernel.org/r/20220908081932.77370-1-xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In lru_sort.c and reclaim.c, they are all defining get_monitoring_region()
function, there is no need to define it separately.
As 'get_monitoring_region()' is not a 'static' function anymore, we try to
use a prefix to distinguish with other functions, so there rename it to
'damon_find_biggest_system_ram'.
Link: https://lkml.kernel.org/r/20220909213606.136221-1-sj@kernel.org
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit b18402726b ("Docs/admin-guide/mm/damon/usage: document DAMON
sysfs interface") announced the DAMON debugfs interface deprecation plan,
but it is not so aggressively announced. As the deprecation time is
coming, this commit makes the announce more easy to be found by adding the
note to the config menu of DAMON debugfs interface.
Link: https://lkml.kernel.org/r/20220909202901.57977-6-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>
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>
When there are two or more non-contiguous regions intersecting with given
new ranges, 'damon_set_regions()' does not fill the holes. This commit
makes the function to fill the holes with newly created regions.
[sj@kernel.org: handle error from 'damon_fill_regions_holes()']
Link: https://lkml.kernel.org/r/20220913215420.57761-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20220909202901.57977-3-sj@kernel.org
Fixes: 3f49584b26 ("mm/damon: implement primitives for the virtual memory address spaces")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Yun Levi <ppbuk5246@gmail.com>
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>
The switch case 'DAMOS_STAT' and switch case 'default' have same return
value in damon_va_apply_scheme(), and the 'default' case is for DAMOS
actions that not supported by 'vaddr'. It might make sense to add a
comment here.
[akpm@linux-foundation.org: fx comment grammar]
Link: https://lkml.kernel.org/r/1662606797-23534-1-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>
damon_new_scheme() has too many parameters, so introduce struct
damos_access_pattern to simplify it.
In additon, we can't use a bpf trace kprobe that has more than 5
parameters.
Link: https://lkml.kernel.org/r/20220908191443.129534-1-sj@kernel.org
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In damon_sysfs_before_terminate(), it needs to check whether ctx->ops.id
supports 'DAMON_OPS_VADDR' or 'DAMON_OPS_FVADDR', there we can use
damon_target_has_pid() instead.
Link: https://lkml.kernel.org/r/20220907084116.62053-1-xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We iterate the whole regions list every time to get the first/last regions
intersecting with the specific range in damon_set_regions(), in order to
add new region or resize existing regions to fit in the specific range.
Actually, it is unnecessary to iterate the new added regions and the front
regions that have been checked. Just iterate the regions list from the
current point using list_for_each_entry_from() every time to improve
performance.
The kunit tests passed:
[PASSED] damon_test_apply_three_regions1
[PASSED] damon_test_apply_three_regions2
[PASSED] damon_test_apply_three_regions3
[PASSED] damon_test_apply_three_regions4
Link: https://lkml.kernel.org/r/1662477527-13003-1-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>
It is unnecessary to get the number of the running kdamond to judge
whether kdamonds are busy. Here we can use the
damon_sysfs_kdamond_running() helper and return -EBUSY directly when
finding a running kdamond. Meanwhile, merging with the judgement that a
kdamond has current sysfs command callback request to make the code more
clear.
Link: https://lkml.kernel.org/r/1662302166-13216-1-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>
When damon_sysfs_add_target couldn't find proper task, New allocated
damon_target structure isn't registered yet, So, it's impossible to free
new allocated one by damon_sysfs_destroy_targets.
By calling damon_add_target as soon as allocating new target, Fix this
possible memory leak.
Link: https://lkml.kernel.org/r/20220926160611.48536-1-sj@kernel.org
Fixes: a61ea561c8 ("mm/damon/sysfs: link DAMON for virtual address spaces monitoring")
Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [5.17.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This rather specialised walk can use the VMA iterator. If this proves to
be too slow, we can write a custom routine to find the two largest gaps,
but it will be somewhat complicated, so let's see if we need it first.
Update the kunit test case to use the maple tree. This also fixes an
issue with the kunit testcase not adding the last VMA to the list.
Link: https://lkml.kernel.org/r/20220906194824.2110408-16-Liam.Howlett@oracle.com
Fixes: 17ccae8bb5 (mm/damon: add kunit tests)
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We can get the hotness value from damon_hot_score() directly in
damon_pageout_score() function and improve the code readability.
Link: https://lkml.kernel.org/r/1661766366-20998-1-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>
The damon regions that belong to the same damon target have the same
'struct mm_struct *mm', so it's unnecessary to compare the mm and last_mm
objects among the damon regions in one damon target when checking
accesses. But the check is necessary when the target changed in
'__damon_va_check_accesses()', so we can simplify the whole operation by
using the bool 'same_target' to indicate whether the target changed.
Link: https://lkml.kernel.org/r/1661590971-20893-3-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>
Patch series "mm/damon: Simplify the damon regions access check", v2.
This patchset simplifies the operations when checking the damon regions
accesses.
This patch (of 2):
The parameter 'struct damon_ctx *ctx' isn't used in the functions
__damon_{p,v}a_check_access(), so we can remove it and simplify the
parameter passing.
Link: https://lkml.kernel.org/r/1661590971-20893-1-git-send-email-kaixuxia@tencent.com
Link: https://lkml.kernel.org/r/1661590971-20893-2-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>
pmd_huge() is used to validate if the pmd entry is mapped by a huge page,
also including the case of non-present (migration or hwpoisoned) pmd entry
on arm64 or x86 architectures. This means that pmd_pfn() can not get the
correct pfn number for a non-present pmd entry, which will cause
damon_get_page() to get an incorrect page struct (also may be NULL by
pfn_to_online_page()), making the access statistics incorrect.
This means that the DAMON may make incorrect decision according to the
incorrect statistics, for example, DAMON may can not reclaim cold page
in time due to this cold page was regarded as accessed mistakenly if
DAMOS_PAGEOUT operation is specified.
Moreover it does not make sense that we still waste time to get the page
of the non-present entry. Just treat it as not-accessed and skip it,
which maintains consistency with non-present pte level entries.
So add pmd entry present validation to fix the above issues.
Link: https://lkml.kernel.org/r/58b1d1f5fbda7db49ca886d9ef6783e3dcbbbc98.1660805030.git.baolin.wang@linux.alibaba.com
Fixes: 3f49584b26 ("mm/damon: implement primitives for the virtual memory address spaces")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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>
Use kmalloc(...) rather than kmalloc_array(1, ...) because the number of
elements we are specifying in this case is 1, kmalloc would accomplish the
same thing and we can simplify.
Link: https://lkml.kernel.org/r/20220808220019.1680469-1-klee33@uw.edu
Signed-off-by: Kenneth Lee <klee33@uw.edu>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time. Fix this up by properly calling
dput().
Link: https://lkml.kernel.org/r/20220902191149.112434-1-sj@kernel.org
Fixes: 75c1c2b53c ("mm/damon/dbgfs: support multiple contexts")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When user tries to create a DAMON context via the DAMON debugfs interface
with a name of an already existing context, the context directory creation
fails but a new context is created and added in the internal data
structure, due to absence of the directory creation success check. As a
result, memory could leak and DAMON cannot be turned on. An example test
case is as below:
# cd /sys/kernel/debug/damon/
# echo "off" > monitor_on
# echo paddr > target_ids
# echo "abc" > mk_context
# echo "abc" > mk_context
# echo $$ > abc/target_ids
# echo "on" > monitor_on <<< fails
Return value of 'debugfs_create_dir()' is expected to be ignored in
general, but this is an exceptional case as DAMON feature is depending
on the debugfs functionality and it has the potential duplicate name
issue. This commit therefore fixes the issue by checking the directory
creation failure and immediately return the error in the case.
Link: https://lkml.kernel.org/r/20220821180853.2400-1-sj@kernel.org
Fixes: 75c1c2b53c ("mm/damon/dbgfs: support multiple contexts")
Signed-off-by: Badari Pulavarty <badari.pulavarty@intel.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [ 5.15.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lin, Yang Shi, Anshuman Khandual and Mike Rapoport
- Some kmemleak fixes from Patrick Wang and Waiman Long
- DAMON updates from SeongJae Park
- memcg debug/visibility work from Roman Gushchin
- vmalloc speedup from Uladzislau Rezki
- more folio conversion work from Matthew Wilcox
- enhancements for coherent device memory mapping from Alex Sierra
- addition of shared pages tracking and CoW support for fsdax, from
Shiyang Ruan
- hugetlb optimizations from Mike Kravetz
- Mel Gorman has contributed some pagealloc changes to improve latency
and realtime behaviour.
- mprotect soft-dirty checking has been improved by Peter Xu
- Many other singleton patches all over the place
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Merge tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Most of the MM queue. A few things are still pending.
Liam's maple tree rework didn't make it. This has resulted in a few
other minor patch series being held over for next time.
Multi-gen LRU still isn't merged as we were waiting for mapletree to
stabilize. The current plan is to merge MGLRU into -mm soon and to
later reintroduce mapletree, with a view to hopefully getting both
into 6.1-rc1.
Summary:
- The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe
Lin, Yang Shi, Anshuman Khandual and Mike Rapoport
- Some kmemleak fixes from Patrick Wang and Waiman Long
- DAMON updates from SeongJae Park
- memcg debug/visibility work from Roman Gushchin
- vmalloc speedup from Uladzislau Rezki
- more folio conversion work from Matthew Wilcox
- enhancements for coherent device memory mapping from Alex Sierra
- addition of shared pages tracking and CoW support for fsdax, from
Shiyang Ruan
- hugetlb optimizations from Mike Kravetz
- Mel Gorman has contributed some pagealloc changes to improve
latency and realtime behaviour.
- mprotect soft-dirty checking has been improved by Peter Xu
- Many other singleton patches all over the place"
[ XFS merge from hell as per Darrick Wong in
https://lore.kernel.org/all/YshKnxb4VwXycPO8@magnolia/ ]
* tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (282 commits)
tools/testing/selftests/vm/hmm-tests.c: fix build
mm: Kconfig: fix typo
mm: memory-failure: convert to pr_fmt()
mm: use is_zone_movable_page() helper
hugetlbfs: fix inaccurate comment in hugetlbfs_statfs()
hugetlbfs: cleanup some comments in inode.c
hugetlbfs: remove unneeded header file
hugetlbfs: remove unneeded hugetlbfs_ops forward declaration
hugetlbfs: use helper macro SZ_1{K,M}
mm: cleanup is_highmem()
mm/hmm: add a test for cross device private faults
selftests: add soft-dirty into run_vmtests.sh
selftests: soft-dirty: add test for mprotect
mm/mprotect: fix soft-dirty check in can_change_pte_writable()
mm: memcontrol: fix potential oom_lock recursion deadlock
mm/gup.c: fix formatting in check_and_migrate_movable_page()
xfs: fail dax mount if reflink is enabled on a partition
mm/memcontrol.c: remove the redundant updating of stats_flush_threshold
userfaultfd: don't fail on unrecognized features
hugetlb_cgroup: fix wrong hugetlb cgroup numa stat
...
damon_reclaim_init() allocates a memory chunk for ctx with
damon_new_ctx(). When damon_select_ops() fails, ctx is not released,
which will lead to a memory leak.
We should release the ctx with damon_destroy_ctx() when damon_select_ops()
fails to fix the memory leak.
Link: https://lkml.kernel.org/r/20220714063746.2343549-1-niejianglei2021@163.com
Fixes: 4d69c34578 ("mm/damon/reclaim: use damon_select_ops() instead of damon_{v,p}a_set_operations()")
Signed-off-by: Jianglei Nie <niejianglei2021@163.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_lru_sort_init() returns an error when damon_select_ops() fails
without freeing 'ctx' which allocated before. This commit fixes the
potential memory leak by freeing 'ctx' under the situation.
Link: https://lkml.kernel.org/r/20220714170458.49727-1-sj@kernel.org
Fixes: 40e983cca9 ("mm/damon: introduce DAMON-based LRU-lists Sorting")
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Users can do data access-aware LRU-lists sorting using 'LRU_PRIO' and
'LRU_DEPRIO' DAMOS actions. However, finding best parameters including
the hotness/coldness thresholds, CPU quota, and watermarks could be
challenging for some users. To make the scheme easy to be used without
complex tuning for common situations, this commit implements a static
kernel module called 'DAMON_LRU_SORT' using the 'LRU_PRIO' and
'LRU_DEPRIO' DAMOS actions.
It proactively sorts LRU-lists using DAMON with conservatively chosen
default values of the parameters. That is, the module under its default
parameters will make no harm for common situations but provide some level
of efficiency improvements for systems having clear hot/cold access
pattern under a level of memory pressure while consuming only a limited
small portion of CPU time.
Link: https://lkml.kernel.org/r/20220613192301.8817-9-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>
This commit adds a new DAMON-based operation scheme action called
'LRU_DEPRIO' for physical address space. The action deprioritizes pages
in the memory area of the target access pattern on their LRU lists. This
is hence supposed to be used for rarely accessed (cold) memory regions so
that cold pages could be more likely reclaimed first under memory
pressure. Internally, it simply calls 'lru_deactivate()'.
Using this with 'LRU_PRIO' action for hot pages, users can proactively
sort LRU lists based on the access pattern. That is, it can make the LRU
lists somewhat more trustworthy source of access temperature. As a
result, efficiency of LRU-lists based mechanisms including the reclamation
target selection could be improved.
Link: https://lkml.kernel.org/r/20220613192301.8817-7-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>
This commit adds a new DAMOS action called 'LRU_PRIO' for the physical
address space. The action prioritizes pages in the memory regions of the
user-specified target access pattern on their LRU lists. This is hence
supposed to be used for frequently accessed (hot) memory regions so that
hot pages could be more likely protected under memory pressure.
Internally, it simply calls 'mark_page_accessed()'.
Link: https://lkml.kernel.org/r/20220613192301.8817-5-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>
This commit moves code for 'DAMOS_PAGEOUT' handling of the physical
address space monitoring operations set to a separate function so that its
caller, 'damon_pa_apply_scheme()', can be more easily extended for
additional DAMOS actions later.
Link: https://lkml.kernel.org/r/20220613192301.8817-4-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>
Patch series "Extend DAMOS for Proactive LRU-lists Sorting".
Introduction
============
In short, this patchset 1) extends DAMON-based Operation Schemes (DAMOS)
for low overhead data access pattern based LRU-lists sorting, and 2)
implements a static kernel module for easy use of conservatively-tuned
version of that using the extended DAMOS capability.
Background
----------
As page-granularity access checking overhead could be significant on huge
systems, LRU lists are normally not proactively sorted but partially and
reactively sorted for special events including specific user requests,
system calls and memory pressure. As a result, LRU lists are sometimes
not so perfectly prepared to be used as a trustworthy access pattern
source for some situations including reclamation target pages selection
under sudden memory pressure.
DAMON-based Proactive LRU-lists Sorting
---------------------------------------
Because DAMON can identify access patterns of best-effort accuracy while
inducing only user-specified range of overhead, using DAMON for Proactive
LRU-lists Sorting (PLRUS) could be helpful for this situation. The idea
is quite simple. Find hot pages and cold pages using DAMON, and
prioritize hot pages while deprioritizing cold pages on their LRU-lists.
This patchset extends DAMON to support such schemes by introducing a
couple of new DAMOS actions for prioritizing and deprioritizing memory
regions of specific access patterns on their LRU-lists. In detail, this
patchset simply uses 'mark_page_accessed()' and 'deactivate_page()'
functions for prioritization and deprioritization of pages on their LRU
lists, respectively.
To make the scheme easy to use without complex tuning for common
situations, this patchset further implements a static kernel module called
'DAMON_LRU_SORT' using the extended DAMOS functionality. It proactively
sorts LRU-lists using DAMON with conservatively chosen default
hotness/coldness thresholds and small CPU usage quota limit. That is, the
module under its default parameters will make no harm for common situation
but provide some level of benefit for systems having clear hot/cold access
pattern under only memory pressure while consuming only limited small
portion of CPU time.
Related Works
-------------
Proactive reclamation is well known to be helpful for reducing non-optimal
reclamation target selection caused performance drops. However, proactive
reclamation is not a best option for some cases, because it could incur
additional I/O. For an example, it could be prohitive for systems using
storage devices that total number of writes is limited, or cloud block
storages that charges every I/O.
Some proactive reclamation approaches[1,2] induce a level of memory
pressure using memcg files or swappiness while monitoring PSI. As
reclamation target selection is still relying on the original LRU-lists
mechanism, using DAMON-based proactive reclamation before inducing the
proactive reclamation could allow more memory saving with same level of
performance overhead, or less performance overhead with same level of
memory saving.
[1] https://blogs.oracle.com/linux/post/anticipating-your-memory-needs
[2] https://www.pdl.cmu.edu/ftp/NVM/tmo_asplos22.pdf
Evaluation
==========
In short, PLRUS achieves 10% memory PSI (some) reduction, 14% major page
faults reduction, and 3.74% speedup under memory pressure.
Setup
-----
To show the effect of PLRUS, I run PARSEC3 and SPLASH-2X benchmarks under
below variant systems and measure a few metrics including the runtime of
each workload, number of system-wide major page faults, and system-wide
memory PSI (some).
- orig: v5.18-rc4 based mm-unstable kernel + this patchset, but no DAMON scheme
applied.
- mprs: Same to 'orig' but artificial memory pressure is induced.
- plrus: Same to 'mprs' but a radically tuned PLRUS scheme is applied to the
entire physical address space of the system.
For the artificial memory pressure, I set 'memory.limit_in_bytes' to 75%
of the running workload's peak RSS, wait 1 second, remove the pressure by
setting it to 200% of the peak RSS, wait 10 seconds, and repeat the
procedure until the workload finishes[1]. I use zram based swap device.
The tests are automated[2].
[1] https://github.com/awslabs/damon-tests/blob/next/perf/runners/back/0009_memcg_pressure.sh
[2] https://github.com/awslabs/damon-tests/blob/next/perf/full_once_config.sh
Radically Tuned PLRUS
---------------------
To show effect of PLRUS on the PARSEC3/SPLASH-2X workloads which runs for
no long time, we use radically tuned version of PLRUS. The version asks
DAMON to do the proactive LRU-lists sorting as below.
1. Find any memory regions shown some accesses (approximately >=20 accesses per
100 sampling) and prioritize pages of the regions on their LRU lists using
up to 2% CPU time. Under the CPU time limit, prioritize regions having
higher access frequency and kept the access frequency longer first.
2. Find any memory regions shown no access for at least >=5 seconds and
deprioritize pages of the rgions on their LRU lists using up to 2% CPU time.
Under the CPU time limit, deprioritize regions that not accessed for longer
time first.
Results
-------
I repeat the tests 25 times and calculate average of the measured numbers.
The results are as below:
metric orig mprs plrus plrus/mprs
runtime_seconds 190.06 292.83 281.87 0.96
pgmajfaults 852.55 8769420.00 7525040.00 0.86
memory_psi_some_us 106911.00 6943420.00 6220920.00 0.90
The first row is for legend. The first cell shows the metric that the
following cells of the row shows. Second, third, and fourth cells show
the metrics under the configs shown at the first row of the cell, and the
fifth cell shows the metric under 'plrus' divided by the metric under
'mprs'. Second row shows the averaged runtime of the workloads in
seconds. Third row shows the number of system-wide major page faults
while the test was ongoing. Fourth row shows the system-wide memory
pressure stall for some processes in microseconds while the test was
ongoing.
In short, PLRUS achieves 10% memory PSI (some) reduction, 14% major page
faults reduction, and 3.74% speedup under memory pressure. We also
confirmed the CPU usage of kdamond was 2.61% of single CPU, which is below
4% as expected.
Sequence of Patches
===================
The first and second patch cleans up DAMON debugfs interface and
DAMOS_PAGEOUT handling code of physical address space monitoring
operations implementation for easier extension of the code.
The thrid and fourth patches implement a new DAMOS action called
'lru_prio', which prioritizes pages under memory regions which have a
user-specified access pattern, and document it, respectively. The fifth
and sixth patches implement yet another new DAMOS action called
'lru_deprio', which deprioritizes pages under memory regions which have a
user-specified access pattern, and document it, respectively.
The seventh patch implements a static kernel module called
'damon_lru_sort', which utilizes the DAMON-based proactive LRU-lists
sorting under conservatively chosen default parameter. Finally, the
eighth patch documents 'damon_lru_sort'.
This patch (of 8):
DAMON debugfs interface assumes users will write 'damos_action' value
directly to the 'schemes' file. This makes adding new 'damos_action' in
the middle of its definition breaks the backward compatibility of DAMON
debugfs interface, as values of some 'damos_action' could be changed. To
mitigate the situation, this commit adds mappings between the user inputs
and 'damos_action' value and makes DAMON debugfs code uses those.
Link: https://lkml.kernel.org/r/20220613192301.8817-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20220613192301.8817-2-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>
This commit adds 'damon_reclaim_' prefix to 'enabled_store()', so that we
can distinguish it easily from the stack trace using 'faddr2line.sh' like
tools.
Link: https://lkml.kernel.org/r/20220606182310.48781-7-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>
DAMON_RECLAIM's 'enabled' parameter store callback ('enabled_store()')
schedules the parameter check timer ('damon_reclaim_timer') if the
parameter is set as 'Y'. Then, the timer schedules itself to check if
user has set the parameter as 'N'. It's unnecessarily complex.
This commit makes it simpler by making the parameter store callback to
schedule the timer regardless of the parameter value and disabling the
timer's self scheduling.
Link: https://lkml.kernel.org/r/20220606182310.48781-6-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>
DAMON sysfs interface's DAMON context building and its online parameter
update have duplicated code. This commit removes the duplicate.
Link: https://lkml.kernel.org/r/20220606182310.48781-5-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>
DAMON_RECLAIM's handling of 'commit_inputs' parameter is duplicated in
'after_aggregation()' and 'after_wmarks_check()' callbacks. This commit
deduplicates the code for better maintenance.
Link: https://lkml.kernel.org/r/20220606182310.48781-4-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>
The function for knowing if given monitoring context's targets will have
pid or not is defined and used in dbgfs only. However, the logic is also
needed for sysfs. This commit moves the code to damon.h and makes both
dbgfs and sysfs to use it.
Link: https://lkml.kernel.org/r/20220606182310.48781-3-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>
The huge_ptep_set_access_flags() can not make the huge pte old according
to the discussion [1], that means we will always mornitor the young state
of the hugetlb though we stopped accessing the hugetlb, as a result DAMON
will get inaccurate accessing statistics.
So changing to use set_huge_pte_at() to make the huge pte old to fix this
issue.
[1] https://lore.kernel.org/all/Yqy97gXI4Nqb7dYo@arm.com/
Link: https://lkml.kernel.org/r/1655692482-28797-1-git-send-email-baolin.wang@linux.alibaba.com
Fixes: 49f4203aae ("mm/damon: add access checking for hugetlb pages")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 059342d1dd ("mm/damon/reclaim: fix the timer always stays
active") made DAMON_RECLAIM's 'enabled' parameter store callback,
'enabled_store()', to schedule 'damon_reclaim_timer'. The scheduling uses
'system_wq', which is initialized in 'workqueue_init_early()'. As kernel
parameters parsing function ('parse_args()') is called before
'workqueue_init_early()', 'enabled_store()' can be executed before
'workqueue_init_early()' and end up accessing the uninitialized
'system_wq'. As a result, the booting hang[1]. This commit fixes the
issue by checking if the initialization is done before scheduling the
timer.
[1] https://lkml.kernel.org/20220604192222.1488-1-sj@kernel.org/
Link: https://lkml.kernel.org/r/20220604195051.1589-1-sj@kernel.org
Fixes: 059342d1dd ("mm/damon/reclaim: fix the timer always stays active")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Greg White <gwhite@kupulau.com>
Cc: Hailong Tu <tuhailong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_RECLAIM reads the user input parameters only when it starts. To
allow more efficient online tuning, this commit implements a new input
parameter called 'commit_inputs'. Writing true to the parameter makes
DAMON_RECLAIM reads the input parameters again.
Link: https://lkml.kernel.org/r/20220429160606.127307-14-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently, DAMON sysfs interface doesn't provide a way for adjusting DAMON
input parameters while it is turned on. Therefore, users who want to
reconfigure DAMON need to stop DAMON and restart. This means all the
monitoring results that accumulated so far, which could be useful, should
be flushed. This would be inefficient for many cases.
For an example, let's suppose a sysadmin was running a DAMON-based
Operation Scheme to find memory regions not accessed for more than 5 mins
and page out the regions. If it turns out the 5 mins threshold was too
long and therefore the sysadmin wants to reduce it to 4 mins, the sysadmin
should turn off DAMON, restart it, and wait for at least 4 more minutes so
that DAMON can find the cold memory regions, even though DAMON was knowing
there are regions that not accessed for 4 mins at the time of shutdown.
This commit makes DAMON sysfs interface to support online DAMON input
parameters updates by adding a new input keyword for the 'state' DAMON
sysfs file, 'commit'. Writing the keyword to the 'state' file while the
corresponding kdamond is running makes the kdamond to read the sysfs file
values again and update the DAMON context.
Link: https://lkml.kernel.org/r/20220429160606.127307-12-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Only '->kdamond' and '->kdamond_stop' are protected by 'kdamond_lock' of
'struct damon_ctx'. All other DAMON context internal data items are
recommended to be accessed in DAMON callbacks, or under some additional
synchronizations. But, DAMON sysfs is accessing the schemes stat under
'kdamond_lock'.
It makes no big issue as the read values are not used anywhere inside
kernel, but would better to be fixed. This commit moves the reads to
DAMON callback context, as supposed to be used for the purpose.
Link: https://lkml.kernel.org/r/20220429160606.127307-11-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON sysfs 'state' file handling code is using string literals in both
'state_show()' and 'state_store()'. This makes the code error prone and
inflexible for future extensions.
To improve the situation, this commit defines possible input strings and
'enum' for identifying each input keyword only once, and refactors the
code to reuse those.
Link: https://lkml.kernel.org/r/20220429160606.127307-10-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
'damon_set_regions()' is general enough so that it can also be used for
only creating regions. This commit makes DAMON sysfs interface to reuse
the function rather keeping two implementations for a same purpose.
Link: https://lkml.kernel.org/r/20220429160606.127307-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit separates DAMON sysfs interface's monitoring context targets
setup code to a new function for better readability.
Link: https://lkml.kernel.org/r/20220429160606.127307-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Having multiple targets for physical address space monitoring makes no
sense. This commit prohibits such a ridiculous DAMON context setup my
making the DAMON context build function to check and return an error for
the case.
Link: https://lkml.kernel.org/r/20220429160606.127307-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
'damon_va_apply_three_regions()' is just a wrapper of its general version,
'damon_set_regions()'. This commit replaces the wrapper calls to directly
call the general version.
Link: https://lkml.kernel.org/r/20220429160606.127307-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit moves 'damon_set_regions()' from vaddr to core, as it is aimed
to be used by not only 'vaddr' but also other parts of DAMON.
Link: https://lkml.kernel.org/r/20220429160606.127307-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
'damon_va_apply_three_regions()' is for adjusting address ranges to fit in
three discontiguous ranges. The function can be generalized for arbitrary
number of discontiguous ranges and reused for future usage, such as
arbitrary online regions update. For such future usage, this commit
introduces a generalized version of the function called
'damon_set_regions()'.
Link: https://lkml.kernel.org/r/20220429160606.127307-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When 'after_sampling()' or 'after_aggregation()' DAMON callbacks return an
error, kdamond continues the remaining loop once. It makes no much sense
to run the remaining part while something wrong already happened. The
context might be corrupted or having invalid data. This commit therefore
makes kdamond skips the remaining works and immediately finish in the
cases.
Link: https://lkml.kernel.org/r/20220429160606.127307-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/damon: Support online tuning".
Effects of DAMON and DAMON-based Operation Schemes highly depends on the
configurations. Wrong configurations could even result in unexpected
efficiency degradations. For finding a best configuration, repeating
incremental configuration changes and results measurements, in other
words, online tuning, could be helpful.
Nevertheless, DAMON kernel API supports only restrictive online tuning.
Worse yet, the sysfs-based DAMON user interface doesn't support online
tuning at all. DAMON_RECLAIM also doesn't support online tuning.
This patchset makes the DAMON kernel API, DAMON sysfs interface, and
DAMON_RECLAIM supports online tuning.
Sequence of patches
-------------------
First two patches enhance DAMON online tuning for kernel API users.
Specifically, patch 1 let kernel API users to be able to do DAMON online
tuning without a restriction, and patch 2 makes error handling easier.
Following seven patches (patches 3-9) refactor code for better readability
and easier reuse of code fragments that will be useful for online tuning
support.
Patch 10 introduces DAMON callback based user request handling structure
for DAMON sysfs interface, and patch 11 enables DAMON online tuning via
DAMON sysfs interface. Documentation patch (patch 12) for usage of it
follows.
Patch 13 enables online tuning of DAMON_RECLAIM and finally patch 14
documents the DAMON_RECLAIM online tuning usage.
This patch (of 14):
For updating input parameters for running DAMON contexts, DAMON kernel API
users can use the contexts' callbacks, as it is the safe place for context
internal data accesses. When the context has DAMON-based operation
schemes and all schemes are deactivated due to their watermarks, however,
DAMON does nothing but only watermarks checks. As a result, no callbacks
will be called back, and therefore the kernel API users cannot update the
input parameters including monitoring attributes, DAMON-based operation
schemes, and watermarks.
To let users easily update such DAMON input parameters in such a case,
this commit adds a new callback, 'after_wmarks_check()'. It will be
called after each watermarks check. Users can do the online input
parameters update in the callback even under the schemes deactivated case.
Link: https://lkml.kernel.org/r/20220429160606.127307-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit makes DAMON sysfs interface to support the fixed virtual
address ranges monitoring. After this commit, writing 'fvaddr' to the
'operations' DAMON sysfs file makes DAMON uses the monitoring operations
set for fixed virtual address ranges, so that users can monitor accesses
to only interested virtual address ranges.
[sj@kernel.org: fix pid leak under fvaddr ops use case]
Link: https://lkml.kernel.org/r/20220503220531.45913-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20220426231750.48822-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "support fixed virtual address ranges monitoring".
The monitoring operations set for virtual address spaces automatically
updates the monitoring target regions to cover entire mappings of the
virtual address spaces as much as possible. Some users could have more
information about their programs than kernel and therefore have interest
in not entire regions but only specific regions. For such cases, the
automatic monitoring target regions updates are only unnecessary overhead
or distractions.
This patchset adds supports for the use case on DAMON's kernel API
(DAMON_OPS_FVADDR) and sysfs interface ('fvaddr' keyword for 'operations'
sysfs file).
This patch (of 3):
The monitoring operations set for virtual address spaces automatically
updates the monitoring target regions to cover entire mappings of the
virtual address spaces as much as possible. Some users could have more
information about their programs than kernel and therefore have interest
in not entire regions but only specific regions. For such cases, the
automatic monitoring target regions updates are only unnecessary overheads
or distractions.
For such cases, DAMON's API users can simply set the '->init()' and
'->update()' of the DAMON context's '->ops' NULL, and set the target
monitoring regions when creating the context. But, that would be a dirty
hack. Worse yet, the hack is unavailable for DAMON user space interface
users.
To support the use case in a clean way that can easily exported to the
user space, this commit adds another monitoring operations set called
'fvaddr', which is same to 'vaddr' but does not automatically update the
monitoring regions. Instead, it will only respect the virtual address
regions which have explicitly passed at the initial context creation.
Note that this commit leave sysfs interface not supporting the feature
yet. The support will be made in a following commit.
Link: https://lkml.kernel.org/r/20220426231750.48822-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20220426231750.48822-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park