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abdca14655fe4ec821791c031d5764fdd1e9484d
1446337
Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 Cheng-Han Wu
|
abdca14655 |
Docs/admin-guide/mm/damon: fix 'parametrs' typo
Fix the misspelling of "parametrs" as "parameters" in reclaim.rst and lru_sort.rst. Link: https://lore.kernel.org/20260426231619.107231-3-sj@kernel.org Signed-off-by: Cheng-Han Wu <hank20010209@gmail.com> Signed-off-by: SeongJae Park <sj@kernel.org> Reviewed-by: SeongJae Park <sj@kernel.org> Cc: Asier Gutierrez <gutierrez.asier@huawei-partners.com> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam R. Howlett <liam@infradead.org> Cc: Liew Rui Yan <aethernet65535@gmail.com> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
 Liew Rui Yan
|
1d258000b0 |
mm/damon/ops-common: optimize damon_hot_score() using ilog2()
Patch series "mm/damon: repost non-hotfix reviewed patches in damon/next
tree", v2.
The first patch from Liew Rui Yan add a minor performance optimization
using ilog2() instead of inefficient manual implementation of the
functionality.
The second patch from Cheng-Han Wu fixes a minor typo:
s/parametrs/parameters/.
The third patch from Liew Rui Yan make commit_inputs operation of
DAMON_RECLAIM and DAMON_LRU_SORT synchronous to improve the user
experience.
The fourth patch from Asier Gutierrez adds a new DAMOS action,
DAMOS_COLLAPSE for deterministic DAMOS-based access-aware THP system.
This patch (of 4):
The current implementation of damon_hot_score() uses a manual for-loop to
calculate the value of 'age_in_log'. This can be efficiently replaced by
ilog2(), which is semantically more appropriate for calculating the
logarithmic value of age.
In a simulated-kernel-module performance test with 10,000,000 iterations,
this optimization showed a significant reduction in latency (average
latency reduced from ~12ns to ~1ns).
Test results from the simulated-kernel-module:
- ilog2:
DAMON Perf Test: Starting 10000000 iterations
=============================================
Total Iterations : 10000000
Average Latency : 1 ns
P95 Latency : 41 ns
P99 Latency : 41 ns
---------------------------------------------
Range (ns) | Count | Percent
---------------------------------------------
0-19 | 0 | 0%
20-39 | 2625000 | 26%
40-59 | 7374000 | 73%
60-79 | 0 | 0%
80-99 | 0 | 0%
100+ | 1000 | 0%
=============================================
- for-loop:
DAMON Perf Test: Starting 10000000 iterations
=============================================
Total Iterations : 10000000
Average Latency : 12 ns
P95 Latency : 51 ns
P99 Latency : 60 ns
---------------------------------------------
Range (ns) | Count | Percent
---------------------------------------------
0-19 | 0 | 0%
20-39 | 0 | 0%
40-59 | 9862000 | 98%
60-79 | 135000 | 1%
80-99 | 1000 | 0%
100+ | 2000 | 0%
=============================================
Full raw benchmark results can be found at [1].
Link: https://lore.kernel.org/20260426231619.107231-1-sj@kernel.org
Link: https://lore.kernel.org/20260426231619.107231-2-sj@kernel.org
Link: https://github.com/aethernet65535/damon-hot-score-fls-optimize/tree/master/result-raw [1]
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Liew Rui Yan <aethernet65535@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Asier Gutierrez <gutierrez.asier@huawei-partners.com>
Cc: Cheng-Han Wu <hank20010209@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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 Muchun Song
|
cd681403a8 |
mm/mm_init: fix uninitialized struct pages for ZONE_DEVICE
If DAX memory is hotplugged into an unoccupied subsection of an early
section, section_activate() reuses the unoptimized boot memmap. However,
compound_nr_pages() still assumes that vmemmap optimization is in effect
and initializes only the reduced number of struct pages. As a result, the
remaining tail struct pages are left uninitialized, which can later lead
to unexpected behavior or crashes.
Fix this by treating early sections as unoptimized when calculating how
many struct pages to initialize.
Link: https://lore.kernel.org/20260428081855.1249045-7-songmuchun@bytedance.com
Fixes:
|
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|
Muchun Song
|
94405c6136 |
mm/mm_init: fix pageblock migratetype for ZONE_DEVICE compound pages
The memmap_init_zone_device() function only initializes the migratetype of the first pageblock of a compound page. If the compound page size exceeds pageblock_nr_pages (e.g., 1GB hugepages with 2MB pageblocks), subsequent pageblocks in the compound page remain uninitialized. Move the migratetype initialization out of __init_zone_device_page() and into a separate pageblock_migratetype_init_range() function. This iterates over the entire PFN range of the memory, ensuring that all pageblocks are correctly initialized. Also remove the stale confusing comment about MEMINIT_HOTPLUG above the migratetype setting since it is an obsolete relic from commit |
||
|
Muchun Song
|
721a73e30c |
mm/sparse-vmemmap: fix DAX vmemmap accounting with optimization
When vmemmap optimization is enabled for DAX, the nr_memmap_pages counter
in /proc/vmstat is incorrect. The current code always accounts for the
full, non-optimized vmemmap size, but vmemmap optimization reduces the
actual number of vmemmap pages by reusing tail pages. This causes the
system to overcount vmemmap usage, leading to inaccurate page statistics
in /proc/vmstat.
Fix this by introducing section_nr_vmemmap_pages(), which returns the
exact vmemmap page count for a given pfn range based on whether
optimization is in effect.
Link: https://lore.kernel.org/20260428081855.1249045-5-songmuchun@bytedance.com
Fixes:
|
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|
Muchun Song
|
3bbc54dd1b |
mm/sparse-vmemmap: pass @pgmap argument to memory deactivation paths
Currently, the memory hot-remove call chain -- arch_remove_memory(), __remove_pages(), sparse_remove_section() and section_deactivate() -- does not carry the struct dev_pagemap pointer. This prevents the lower levels from knowing whether the section was originally populated with vmemmap optimizations (e.g., DAX with vmemmap optimization enabled). Without this information, we cannot call vmemmap_can_optimize() to determine if the vmemmap pages were optimized. As a result, the vmemmap page accounting during teardown will mistakenly assume a non-optimized allocation, leading to incorrect memmap statistics. To lay the groundwork for fixing the vmemmap page accounting, we need to pass the @pgmap pointer down to the deactivation location. Plumb the @pgmap argument through the APIs of arch_remove_memory(), __remove_pages() and sparse_remove_section(), mirroring the corresponding *_activate() paths. Link: https://lore.kernel.org/20260428081855.1249045-4-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Acked-by: Liam R. Howlett <liam@infradead.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Muchun Song
|
2fac4afa0e |
mm/memory_hotplug: fix incorrect altmap passing in error path
In create_altmaps_and_memory_blocks(), when arch_add_memory() succeeds
with memmap_on_memory enabled, the vmemmap pages are allocated from
params.altmap. If create_memory_block_devices() subsequently fails, the
error path calls arch_remove_memory() with a NULL altmap instead of
params.altmap.
This is a bug that could lead to memory corruption. Since altmap is NULL,
vmemmap_free() falls back to freeing the vmemmap pages into the system
buddy allocator via free_pages() instead of the altmap.
arch_remove_memory() then immediately destroys the physical linear mapping
for this memory. This injects unowned pages into the buddy allocator,
causing machine checks or memory corruption if the system later attempts
to allocate and use those freed pages.
Fix this by passing params.altmap to arch_remove_memory() in the error
path.
Link: https://lore.kernel.org/20260428081855.1249045-3-songmuchun@bytedance.com
Fixes:
|
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|
Muchun Song
|
c373f7f98e |
mm/sparse-vmemmap: fix vmemmap accounting underflow
Patch series "mm: Fix vmemmap optimization accounting and initialization", v8. The series fixes several bugs in vmemmap optimization, mainly around incorrect page accounting and memmap initialization in DAX and memory hotplug paths. It also fixes pageblock migratetype initialization and struct page initialization for ZONE_DEVICE compound pages. Patches 1-4 fix vmemmap accounting issues. Patch 1 fixes an accounting underflow in the section activation failure path by moving vmemmap page accounting into the lower-level allocation and freeing helpers. Patch 2 fixes incorrect altmap passing in the memory hotplug error path. Patch 3 passes pgmap through memory deactivation paths so the teardown side can determine whether vmemmap optimization was in effect. Patch 4 uses that information to account the optimized DAX vmemmap size correctly. Patches 5-6 fix initialization issues in mm/mm_init. One makes sure all pageblocks in ZONE_DEVICE compound pages get their migratetype initialized. The other fixes a case where DAX memory hotplug reuses an unoptimized early-section memmap while compound_nr_pages() still assumes vmemmap optimization, leaving tail struct pages uninitialized. This patch (of 6): In section_activate(), if populate_section_memmap() fails, the error handling path calls section_deactivate() to roll back the state. This causes a vmemmap accounting imbalance. Since commit |
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 Dev Jain
|
7e8983f317 |
selftests/mm: simplify byte pattern checking in mremap_test
The original version of mremap_test ( |
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 Davidlohr Bueso
|
8aa442cfce |
dax/kmem: account for partial discontiguous resource upon removal
When dev_dax_kmem_probe() partially succeeds (at least one range is
mapped) but a subsequent range fails request_mem_region() or
add_memory_driver_managed(), the probe silently continues, ultimately
returning success, but with the corresponding range resource NULL'ed out.
dev_dax_kmem_remove() iterates over all dax_device ranges regardless of if
the underlying resource exists. When remove_memory() is called later, it
returns 0 because the memory was never added which causes
dev_dax_kmem_remove() to incorrectly assume the (nonexistent) resource can
be removed and attempts cleanup on a NULL pointer.
Fix this by skipping these ranges altogether, noting that these cases are
considered success, such that the cleanup is still reached when all
actually-added ranges are successfully removed.
Link: https://lore.kernel.org/20260223201516.1517657-1-dave@stgolabs.net
Fixes:
|
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 Brendan Jackman
|
3f99414620 |
net/rds: use special gfp_t format specifier
%pGg produces nice readable output and decouples the format string from the size of gfp_t. Link: https://lore.kernel.org/20260326-gfp64-v2-4-d916021cecdf@google.com Signed-off-by: Brendan Jackman <jackmanb@google.com> Acked-by: Allison Henderson <achender@kernel.org> Cc: Alexander Potapenko <glider@google.com> Cc: Allison Collins <allison.henderson@oracle.com> Cc: Dave Airlie <airlied@gmail.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Jakub Kacinski <kuba@kernel.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Marco Elver <elver@google.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Simon Horman <horms@kernel.org> Cc: Stanislaw Gruszka <stf_xl@wp.pl> Cc: Thomas Zimemrmann <tzimmermann@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Brendan Jackman
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d36102a5f5 |
mm/kfence: use special gfp_t format specifier
%pGg produces nice readable output and decouples the format string from the size of gfp_t. Link: https://lore.kernel.org/20260326-gfp64-v2-3-d916021cecdf@google.com Signed-off-by: Brendan Jackman <jackmanb@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Allison Collins <allison.henderson@oracle.com> Cc: Allison Henderson <achender@kernel.org> Cc: Dave Airlie <airlied@gmail.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Jakub Kacinski <kuba@kernel.org> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Marco Elver <elver@google.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Simon Horman <horms@kernel.org> Cc: Stanislaw Gruszka <stf_xl@wp.pl> Cc: Thomas Zimemrmann <tzimmermann@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Brendan Jackman
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faae0ca362 |
drm/managed: use special gfp_t format specifier
Patch series "treewide: fixup gfp_t printks", v2. Use vprintf()'s special gfp_t conversion in a few places. This patch (of 3): %pGg produces nice readable output and decouples the format string from the size of gfp_t. Link: https://lore.kernel.org/20260326-gfp64-v2-0-d916021cecdf@google.com Link: https://lore.kernel.org/20260326-gfp64-v2-1-d916021cecdf@google.com Signed-off-by: Brendan Jackman <jackmanb@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Allison Collins <allison.henderson@oracle.com> Cc: Allison Henderson <achender@kernel.org> Cc: Dave Airlie <airlied@gmail.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Jakub Kacinski <kuba@kernel.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Marco Elver <elver@google.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Simon Horman <horms@kernel.org> Cc: Stanislaw Gruszka <stf_xl@wp.pl> Cc: Thomas Zimemrmann <tzimmermann@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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 Deepanshu Kartikey
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15807d0ddd |
mm/hugetlb: fix hugetlb cgroup rsvd charge/uncharge mismatch
In alloc_hugetlb_folio(), a single h_cg pointer is used for both the rsvd
and non-rsvd hugetlb cgroup charges. When map_chg is set,
hugetlb_cgroup_charge_cgroup_rsvd() stores the charged cgroup in h_cg, but
the immediately following hugetlb_cgroup_charge_cgroup() overwrites h_cg
with the non-rsvd cgroup pointer.
As a result, hugetlb_cgroup_commit_charge_rsvd() stores the wrong
(non-rsvd) cgroup pointer into the folio's rsvd slot.
When the folio is later freed, free_huge_folio() unconditionally calls
both hugetlb_cgroup_uncharge_folio() and
hugetlb_cgroup_uncharge_folio_rsvd(). The rsvd uncharge reads back the
wrong cgroup from the folio and decrements a counter that was never
charged for that cgroup, causing a page_counter underflow:
page_counter underflow: -512 nr_pages=512
WARNING: mm/page_counter.c:61 at page_counter_cancel
Fix this by introducing a separate h_cg_rsvd pointer exclusively for the
rsvd charge path, keeping the rsvd and non-rsvd charges fully independent
through their charge, commit, and error uncharge paths.
Link: https://lore.kernel.org/20260328065534.346053-1-kartikey406@gmail.com
Fixes:
|
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 JP Kobryn (Meta)
|
9669b87065 |
mm/lruvec: preemptively free dead folios during lru_add drain
Of all observable lruvec lock contention in our fleet, we find that ~24%
occurs when dead folios are present in lru_add batches at drain time.
This is wasteful in the sense that the folio is added to the LRU just to
be immediately removed via folios_put_refs(), incurring two unnecessary
lock acquisitions.
Eliminate this overhead by preemptively cleaning up dead folios before
they make it into the LRU. Use folio_ref_freeze() to filter folios whose
only remaining refcount is the batch ref. When dead folios are found,
move them off the add batch and onto a temporary batch to be freed.
PG_active may be set on a batched folio as well as PG_unevictable (via
migration path). Since filtered folios bypass the normal lru_add()
cleanup, both flags must be cleared before freeing.
During A/B testing on one of our prod instagram workloads (high-frequency
short-lived requests), the patch intercepted almost all dead folios before
they entered the LRU. Data collected using the mm_lru_insertion
tracepoint shows the effectiveness of the patch:
Per-host LRU add averages at 95% CPU load
(60 hosts each side, 3 x 60s intervals)
dead folios/min total folios/min dead %
unpatched: 1,297,785 19,341,986 6.7097%
patched: 14 19,039,996 0.0001%
Within this workload, we save ~2.6M lock acquisitions per minute per host
as a result.
System-wide memory stats improved on the patched side also at 95% CPU load:
- direct reclaim scanning reduced 7%
- allocation stalls reduced 5.2%
- compaction stalls reduced 12.3%
- page frees reduced 4.9%
No regressions were observed in requests served per second or request tail
latency (p99). Both metrics showed directional improvement at higher CPU
utilization (comparing 85% to 95%).
Note that tests were performed using classic LRU.
Link: https://lore.kernel.org/20260425053417.351146-1-jp.kobryn@linux.dev
Signed-off-by: JP Kobryn (Meta) <jp.kobryn@linux.dev>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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 David Rientjes
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94e0bcde05 |
mm, page_alloc: reintroduce page allocation stall warning
Previously, we had warnings when a single page allocation took longer than reasonably expected. This was introduced in commit |
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 Julian Braha
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b9fe373e7d |
mm/thp: dead code cleanup in Kconfig
There is already an 'if TRANSPARENT_HUGEPAGE' condition wrapping several config options e.g. 'READ_ONLY_THP_FOR_FS', making the 'depends on' statement for each of these a duplicate dependency (dead code). I propose leaving the outer 'if TRANSPARENT_HUGEPAGE...endif' and removing the individual 'depends on TRANSPARENT_HUGEPAGE' statement from each option. This dead code was found by kconfirm, a static analysis tool for Kconfig. Link: https://lore.kernel.org/20260331070730.33915-1-julianbraha@gmail.com Signed-off-by: Julian Braha <julianbraha@gmail.com> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Liam Howlett <liam@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Brendan Jackman
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1d05e1f6ac |
mm/page_alloc: cleanup flag vars in alloc_pages_bulk_noprof()
These two variables are redundant, squash them to align alloc_pages_bulk_noprof() with the style used in alloc_frozen_pages_nolock_noprof(). Link: https://lore.kernel.org/20260331-b4-prepare_alloc_pages-flags-v1-1-ea2416def698@google.com Signed-off-by: Brendan Jackman <jackmanb@google.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Vishal Moola <vishal.moola@gmail.com> Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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 wangxuewen
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c70a9f639b |
mm/memory-failure: replace magic number 3 with GET_PAGE_MAX_RETRY_NUM
Replace the hardcoded magic number 3 in get_any_page() with the existing GET_PAGE_MAX_RETRY_NUM macro for code consistency and maintainability. This change has no functional impact, only improves code readability and unifies the retry limit configuration. Link: https://lore.kernel.org/20260402064946.1124250-1-18810879172@163.com Signed-off-by: wangxuewen <wangxuewen@kylinos.cn> Acked-by: SeongJae Park <sj@kernel.org> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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 David Carlier
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d590df11be |
mm/page_io: rename swap_iocb fields for clarity
swap_iocb->pages tracks the number of bvec entries (folios), not base pages. Rename the array from bvec to bvecs and the counter from pages to nr_bvecs to accurately reflect their purpose. Link: https://lore.kernel.org/20260402072650.48811-1-devnexen@gmail.com Signed-off-by: David Carlier <devnexen@gmail.com> Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org> Suggested-by: David Hildenbrand <david@redhat.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Acked-by: Chris Li <chrisl@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Kairui Song <kasong@tencent.com> Cc: Kemeng Shi <shikemeng@huaweicloud.com> Cc: NeilBrown <neil@brown.name> Cc: Nhat Pham <nphamcs@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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JP Kobryn (Meta)
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f2a950170f |
mm/vmpressure: skip socket pressure for costly order reclaim
When reclaim is triggered by high order allocations on a fragmented system, vmpressure() can report poor reclaim efficiency even though the system has plenty of free memory. This is because many pages are scanned, but few are found to actually reclaim - the pages are actively in use and don't need to be freed. The resulting scan:reclaim ratio causes vmpressure() to assert socket pressure, throttling TCP throughput unnecessarily. Costly order allocations (above PAGE_ALLOC_COSTLY_ORDER) rely heavily on compaction to succeed, so poor reclaim efficiency at these orders does not necessarily indicate memory pressure. The kernel already treats this order as the boundary where reclaim is no longer expected to succeed and compaction may take over. Make vmpressure() order-aware through an additional parameter sourced from scan_control at existing call sites. Socket pressure is now only asserted when order <= PAGE_ALLOC_COSTLY_ORDER. Memcg reclaim is unaffected since try_to_free_mem_cgroup_pages() always uses order 0, which passes the filter unconditionally. Similarly, vmpressure_prio() now passes order 0 internally when calling vmpressure(), ensuring critical pressure from low reclaim priority is not suppressed by the order filter. The patch was motivated by a case of impacted net throughput in production. On one affected host, the memory state at the time showed ~15GB available, zero cgroup pressure, and the following buddyinfo state: Order FreePages 0: 133,970 1: 29,230 2: 17,351 3: 18,984 7+: 0 Using bpf, it was found that 94% of vmpressure calls on this host were from order-7 kswapd reclaim. TCP minimum recv window is rcv_ssthresh:19712. Before patch: 723 out of 3,843 (19%) TCP connections stuck at minimum recv window After live-patching and ~30min elapsed: 0 out of 3,470 TCP connections stuck at minimum recv window Link: https://lore.kernel.org/20260406195014.112521-1-jp.kobryn@linux.dev Signed-off-by: JP Kobryn (Meta) <jp.kobryn@linux.dev> Reviewed-by: Rik van Riel <riel@surriel.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Barry Song <baohua@kernel.org> Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@kernel.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Kairui Song <kasong@tencent.com> Cc: Liam Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Qi Zheng <qi.zheng@linux.dev> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Wei Xu <weixugc@google.com> Cc: Yuanchu Xie <yuanchu@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
 Breno Leitao
|
1d8274b82c |
mm: huge_memory: refactor defrag_show() to use defrag_flags[]
Replace the hardcoded if/else chain of test_bit() calls and string literals in defrag_show() with a loop over defrag_flags[] and defrag_mode_strings[] arrays introduced in the previous commit. This makes defrag_show() consistent with defrag_store() and eliminates the duplicated mode name strings. Link: https://lore.kernel.org/20260408-thp_defrag-v2-2-bc544c1bde4e@debian.org Signed-off-by: Breno Leitao <leitao@debian.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Tested-by: Lance Yang <lance.yang@linux.dev> Reviewed-by: Lance Yang <lance.yang@linux.dev> Reviewed-by: Barry Song <baohua@kernel.org> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Tested-by: Zi Yan <ziy@nvidia.com> Acked-by: Zi Yan <ziy@nvidia.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Liam Howlett <liam@infradead.org> Cc: Nico Pache <npache@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Breno Leitao
|
b0f3d00e15 |
mm: huge_memory: use sysfs_match_string() in defrag_store()
Patch series "mm: huge_memory: clean up defrag sysfs with shared", v2.
Refactor defrag_store() and defrag_show() to use shared data tables
instead of duplicated if/else chains.
Patch 1 introduces an enum defrag_mode, a defrag_mode_strings[] table, and
a defrag_flags[] mapping array, then rewrites defrag_store() to use
sysfs_match_string() with a loop over defrag_flags[].
Patch 2 refactors defrag_show() to use the same arrays, replacing its
hardcoded if/else chain of test_bit() calls and string literals.
This follows the same pattern applied to anon_enabled_store() in commit
522dfb4ba71f ("mm: huge_memory: refactor anon_enabled_store() with
change_anon_orders()").
This patch (of 2):
Replace the if/else chain of sysfs_streq() calls in defrag_store() with
sysfs_match_string() and a defrag_mode_strings[] table.
Introduce enum defrag_mode and defrag_flags[] array mapping each mode to
its corresponding transparent_hugepage_flag. The store function now loops
over defrag_flags[], setting the bit for the selected mode and clearing
the others. When mode is DEFRAG_NEVER (index 4), no index in the
4-element defrag_flags[] matches, so all flags are cleared.
Note that the enum ordering (always, defer, defer+madvise, madvise, never)
differs from the original if/else chain order in defrag_store() (always,
defer+madvise, defer, madvise, never). This is intentional to match the
display order used by defrag_show().
This is a follow-up cleanup to commit 522dfb4ba71f ("mm: huge_memory:
refactor anon_enabled_store() with change_anon_orders()") which applied
the same sysfs_match_string() pattern to anon_enabled_store().
Link: https://lore.kernel.org/20260408-thp_defrag-v2-0-bc544c1bde4e@debian.org
Link: https://lore.kernel.org/20260408-thp_defrag-v2-1-bc544c1bde4e@debian.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Tested-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Barry Song <baohua@kernel.org>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Tested-by: Zi Yan <ziy@nvidia.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam@infradead.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
 Ye Liu
|
98e09ce7bb |
mm/khugepaged: use ALIGN helpers for PMD alignment
PMD alignment in khugepaged is currently implemented using a mix of rounding helpers and open-coded bitmask operations. Use ALIGN() and ALIGN_DOWN() consistently for PMD-sized address range alignment, matching the preferred style for address and size handling. No functional change intended. Link: https://lore.kernel.org/20260409014323.2385982-1-ye.liu@linux.dev Signed-off-by: Ye Liu <liuye@kylinos.cn> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Barry Song <baohua@kernel.org> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: SeongJae Park <sj@kernel.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam@infradead.org> Cc: Liu Ye <liuye@kylinos.cn> Cc: Nico Pache <npache@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Ye Liu
|
db5e2c01ca |
mm/memory-failure: use bool for forcekill state
'forcekill' is used as a boolean flag to control whether processes should be forcibly killed. It is only assigned from boolean expressions and never used in arithmetic or bitmask operations. Convert it from int to bool. No functional change intended. Link: https://lore.kernel.org/20260410074740.2524718-1-ye.liu@linux.dev Signed-off-by: Ye Liu <liuye@kylinos.cn> Reviewed-by: SeongJae Park <sj@kernel.org> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Liu Ye <liuye@kylinos.cn> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Muchun Song
|
ffe5539313 |
mm/sparse: remove sparse buffer pre-allocation mechanism
Commit
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 SeongJae Park
|
8c2c7df58b |
Docs/mm/damon/maintainer-profile: add AI review usage guideline
DAMON is opted-in for DAMON patches scanning [1] and email delivery [2]. Clarify how that could be used on DAMON maintainer profile. Link: https://lore.kernel.org/20260412211932.89038-1-sj@kernel.org Link: https://github.com/sashiko-dev/sashiko/commit/ad9f4a98f958 [1] Link: https://github.com/sashiko-dev/sashiko/commit/b554c7b6e733 [2] Signed-off-by: SeongJae Park <sj@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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 Zhen Ni
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781b0e7474 |
mm/page_owner: fix %pGp format specifier argument type
The %pGp format specifier expects an argument of type 'unsigned long *',
but page->flags is now of type 'memdesc_flags_t' (a struct containing an
unsigned long member 'f') after the introduction of memdesc_flags_t.
Fix the type mismatch by passing &page->flags.f instead of &page->flags,
which matches the expected type.
Link: https://lore.kernel.org/20260414075813.3425968-1-zhen.ni@easystack.cn
Fixes:
|
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 Anthony Yznaga
|
303c6bdfe7 |
selftests/mm: run the MAP_DROPPABLE selftest
The test was not being run by the selftest framework so it was never noticed that it would fail with an assertion failure on configs without support for MAP_DROPPABLE. Update the test so that it is skipped instead when MAP_DROPPABLE is not supported, and add it to the mmap category so that the test is run by the framework. Link: https://lore.kernel.org/20260416033939.49981-4-anthony.yznaga@oracle.com Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Jason A. Donenfeld <jason@zx2c4.com> Cc: Liam Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Mark Brown <broonie@kernel.org> Cc: Vlastimil Babka (SUSE) <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Anthony Yznaga
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c02dd57c57 |
selftests/mm: verify droppable mappings cannot be locked
For configs that support MAP_DROPPABLE verify that a mapping created with MAP_DROPPABLE cannot be locked via mlock(), and that it will not be locked if it's created after mlockall(MCL_FUTURE). Link: https://lore.kernel.org/20260416033939.49981-3-anthony.yznaga@oracle.com Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Jason A. Donenfeld <jason@zx2c4.com> Cc: Liam Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Mark Brown <broonie@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka (SUSE) <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Anthony Yznaga
|
d86c9e971a |
mm: fix mmap errno value when MAP_DROPPABLE is not supported
Patch series "fix MAP_DROPPABLE not supported errno", v4.
Mark Brown reported seeing a regression in -next on 32 bit arm with the
mlock selftests. Before exiting and marking the tests failed, the
following message was logged after an attempt to create a MAP_DROPPABLE
mapping:
Bail out! mmap error: Unknown error 524
It turns out error 524 is ENOTSUPP which is an error that userspace is not
supposed to see, but it indicates in this instance that MAP_DROPPABLE is
not supported.
The first patch changes the errno returned to EOPNOTSUPP. The second
patch is a second version of a prior patch to introduce selftests to
verify locking behavior with droppable mappings with the additional change
to skip the tests when MAP_DROPPABLE is not supported. The third patch
fixes the MAP_DROPPABLE selftest so that it is run by the framework and
skips if MAP_DROPPABLE is not supported.
This patch (of 3):
On configs where MAP_DROPPABLE is not supported (currently any 32-bit
config except for PPC32), mmap fails with errno set to ENOTSUPP. However,
ENOTSUPP is not a standard error value that userspace knows about. The
acceptable userspace-visible errno to use is EOPNOTSUPP. checkpatch.pl
has a warning to this effect.
Link: https://lore.kernel.org/20260416033939.49981-1-anthony.yznaga@oracle.com
Link: https://lore.kernel.org/20260416033939.49981-2-anthony.yznaga@oracle.com
Fixes:
|
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 Xiang Gao
|
eb8fc9d285 |
mm/vmscan: fix typos in comments
Fix three typos in comments: - Line 112: "zome_reclaim_mode" -> "zone_reclaim_mode" - Line 6208: "prioities" -> "priorities" - Line 7067: "that that high" -> "that the high" (duplicated word) Link: https://lore.kernel.org/20260416062302.727468-1-gxxa03070307@gmail.com Signed-off-by: Xiang Gao <gaoxiang17@xiaomi.com> Reviewed-by: Barry Song <baohua@kernel.org> Reviewed-by: Donet Tom <donettom@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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 Sang-Heon Jeon
|
e0974347f5 |
mm/sparse: remove unnecessary NULL check before allocating mem_section
Commit
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||
 Sunny Patel
|
13fe573656 |
mm/migrate_device: cleanup up PMD Checks and warnings
Remove the odd VM_WARN_ON_FOLIO(!folio, folio) usage and replace it with a simpler VM_WARN_ON_ONCE(!folio) check. Drop the redundant VM_WARN_ON_ONCE(!pmd_none(*pmdp) && !is_huge_zero_pmd(*pmdp)). Refactor the PMD checks, making the control flow clearer and avoiding duplicate condition checks. Link: https://lore.kernel.org/20260419174747.10701-1-nueralspacetech@gmail.com Signed-off-by: Sunny Patel <nueralspacetech@gmail.com> Acked-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Huang Ying <ying.huang@linux.alibaba.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Alistair Popple <apopple@nvidia.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Rakie Kim <rakie.kim@sk.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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 Li Wang
|
e5ab892d05 |
selftests/cgroup: test_zswap: wait for asynchronous writeback
zswap writeback is asynchronous, but test_zswap.c checks writeback counters immediately after reclaim/trigger paths. On some platforms (e.g. ppc64le), this can race with background writeback and cause spurious failures even when behavior is correct. Add wait_for_writeback() to poll get_cg_wb_count() with a bounded timeout, and use it in: test_zswap_writeback_one() when writeback is expected test_no_invasive_cgroup_shrink() for the wb_group check This keeps the original before/after assertion style while making the tests robust against writeback completion latency. No test behavior change, selftest stability improvement only. Link: https://lore.kernel.org/20260424040059.12940-9-li.wang@linux.dev Signed-off-by: Li Wang <li.wang@linux.dev> Acked-by: Nhat Pham <nphamcs@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Jiayuan Chen <jiayuan.chen@linux.dev> Cc: Waiman Long <longman@redhat.com> Cc: Yosry Ahmed <yosry@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Li Wang
|
883015a9c3 |
selftest/cgroup: fix zswap attempt_writeback() on 64K pagesize system
In attempt_writeback(), a memsize of 4M only covers 64 pages on 64K page size systems. When memory.reclaim is called, the kernel prefers reclaiming clean file pages (binary, libc, linker, etc.) over swapping anonymous pages. With only 64 pages of anonymous memory, the reclaim target can be largely or entirely satisfied by dropping file pages, resulting in very few or zero anonymous pages being pushed into zswap. This causes zswap_usage to be extremely small or zero, making zswap_usage/4 insufficient to create meaningful writeback pressure. The test then fails because no writeback is triggered. On 4K page size systems this is not an issue because 4M covers 1024 pages, and file pages are a small fraction of the reclaim target. Fix this by: - Always allocating 1024 pages regardless of page size. This ensures enough anonymous pages to reliably populate zswap and trigger writeback, while keeping the original 4M allocation on 4K systems. - Setting zswap.max to zswap_usage/4 instead of zswap_usage/2 to create stronger writeback pressure, ensuring reclaim reliably triggers writeback even on large page size systems. === Error Log === # uname -rm 6.12.0-211.el10.ppc64le ppc64le # getconf PAGESIZE 65536 # ./test_zswap TAP version 13 1..7 ok 1 test_zswap_usage ok 2 test_swapin_nozswap ok 3 test_zswapin not ok 4 test_zswap_writeback_enabled ... Link: https://lore.kernel.org/20260424040059.12940-8-li.wang@linux.dev Signed-off-by: Li Wang <li.wang@linux.dev> Acked-by: Yosry Ahmed <yosry@kernel.org> Acked-by: Nhat Pham <nphamcs@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Jiayuan Chen <jiayuan.chen@linux.dev> Cc: Waiman Long <longman@redhat.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Li Wang
|
a19b474927 |
selftest/cgroup: fix zswap test_no_invasive_cgroup_shrink on large pagesize system
test_no_invasive_cgroup_shrink sets up two cgroups: wb_group, which is
expected to trigger zswap writeback, and a control group (renamed to
zw_group), which should only have pages sitting in zswap without any
writeback.
There are two problems with the current test:
1) The data patterns are reversed. wb_group uses allocate_bytes(), which
writes only a single byte per page — trivially compressible,
especially by zstd — so compressed pages fit within zswap.max and
writeback is never triggered. Meanwhile, the control group uses
getrandom() to produce hard-to-compress data, but it is the group
that does *not* need writeback.
2) The test uses fixed sizes (10K zswap.max, 10MB allocation) that are
too small on systems with large PAGE_SIZE (e.g. 64K), failing to
build enough memory pressure to trigger writeback reliably.
Fix both issues by:
- Swapping the data patterns: fill wb_group pages with partially
random data (getrandom for page_size/4 bytes) to resist compression
and trigger writeback, and fill zw_group pages with simple repeated
data to stay compressed in zswap.
- Making all size parameters PAGE_SIZE-aware: set allocation size to
PAGE_SIZE * 1024, memory.zswap.max to PAGE_SIZE, and memory.max to
allocation_size / 2 for both cgroups.
- Allocating memory inline instead of via cg_run() so the pages
remain resident throughout the test.
=== Error Log ===
# getconf PAGESIZE
65536
# ./test_zswap
TAP version 13
...
ok 5 test_zswap_writeback_disabled
ok 6 # SKIP test_no_kmem_bypass
not ok 7 test_no_invasive_cgroup_shrink
Link: https://lore.kernel.org/20260424040059.12940-7-li.wang@linux.dev
Signed-off-by: Li Wang <li.wang@linux.dev>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Jiayuan Chen <jiayuan.chen@linux.dev>
Cc: Waiman Long <longman@redhat.com>
Cc: Yosry Ahmed <yosry@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Li Wang
|
43743cc516 |
selftests/cgroup: replace hardcoded page size values in test_zswap
test_zswap uses hardcoded values of 4095 and 4096 throughout as page stride and page size, which are only correct on systems with a 4K page size. On architectures with larger pages (e.g., 64K on arm64 or ppc64), these constants cause memory to be touched at sub-page granularity, leading to inefficient access patterns and incorrect page count calculations, which can cause test failures. Replace all hardcoded 4095 and 4096 values with a global pagesize variable initialized from sysconf(_SC_PAGESIZE) at startup, and remove the redundant local sysconf() calls scattered across individual functions. No functional change on 4K page size systems. Link: https://lore.kernel.org/20260424040059.12940-6-li.wang@linux.dev Signed-off-by: Li Wang <li.wang@linux.dev> Acked-by: Yosry Ahmed <yosry@kernel.org> Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Waiman Long <longman@redhat.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Li Wang
|
6e9f5c2eec |
selftests/cgroup: rename PAGE_SIZE to BUF_SIZE in cgroup_util
The cgroup utility code defines a local PAGE_SIZE macro hardcoded to 4096, which is used primarily as a generic buffer size for reading cgroup and proc files. This naming is misleading because the value has nothing to do with the actual page size of the system. On architectures with larger pages (e.g., 64K on arm64 or ppc64), the name suggests a relationship that does not exist. Additionally, the name can shadow or conflict with PAGE_SIZE definitions from system headers, leading to confusion or subtle bugs. To resolve this, rename the macro to BUF_SIZE to accurately reflect its purpose as a general I/O buffer size. Furthermore, test_memcontrol currently relies on this hardcoded 4K value to stride through memory and trigger page faults. Update this logic to use the actual system page size dynamically. This micro-optimizes the memory faulting process by ensuring it iterates correctly and efficiently based on the underlying architecture's true page size. (This part from Waiman) Link: https://lore.kernel.org/20260424040059.12940-5-li.wang@linux.dev Signed-off-by: Li Wang <li.wang@linux.dev> Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Nhat Pham <nphamcs@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Jiayuan Chen <jiayuan.chen@linux.dev> Cc: Yosry Ahmed <yosry@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Li Wang
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b19ee588e1 |
selftests/cgroup: use runtime page size for zswpin check
test_zswapin compares memory.stat:zswpin (counted in pages) against a byte threshold converted with PAGE_SIZE. In cgroup selftests, PAGE_SIZE is hardcoded to 4096, which makes the conversion wrong on systems with non-4K base pages (e.g. 64K). As a result, the test requires too many pages to pass and fails spuriously even when zswap is working. Use sysconf(_SC_PAGESIZE) for the zswpin threshold conversion so the check matches the actual system page size. Link: https://lore.kernel.org/20260424040059.12940-4-li.wang@linux.dev Signed-off-by: Li Wang <li.wang@linux.dev> Reviewed-by: Yosry Ahmed <yosry@kernel.org> Acked-by: Nhat Pham <nphamcs@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Jiayuan Chen <jiayuan.chen@linux.dev> Cc: Waiman Long <longman@redhat.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Li Wang
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0d38cded3c |
selftests/cgroup: avoid OOM in test_swapin_nozswap
test_swapin_nozswap can hit OOM before reaching its assertions on some setups. The test currently sets memory.max=8M and then allocates/reads 32M with memory.zswap.max=0, which may over-constrain reclaim and kill the workload process. Replace hardcoded sizes with PAGE_SIZE-based values: - control_allocation_size = PAGE_SIZE * 512 - memory.max = control_allocation_size * 3 / 4 - minimum expected swap = control_allocation_size / 4 This keeps the test pressure model intact (allocate/read beyond memory.max to force swap-in/out) while making it more robust across different environments. The test intent is unchanged: confirm that swapping occurs while zswap remains unused when memory.zswap.max=0. === Error Logs === # ./test_zswap TAP version 13 1..7 ok 1 test_zswap_usage not ok 2 test_swapin_nozswap ... # dmesg [271641.879153] test_zswap invoked oom-killer: gfp_mask=0xcc0(GFP_KERNEL), order=0, oom_score_adj=0 [271641.879168] CPU: 1 UID: 0 PID: 177372 Comm: test_zswap Kdump: loaded Not tainted 6.12.0-211.el10.ppc64le #1 VOLUNTARY [271641.879171] Hardware name: IBM,9009-41A POWER9 (architected) 0x4e0202 0xf000005 of:IBM,FW940.02 (UL940_041) hv:phyp pSeries [271641.879173] Call Trace: [271641.879174] [c00000037540f730] [c00000000127ec44] dump_stack_lvl+0x88/0xc4 (unreliable) [271641.879184] [c00000037540f760] [c0000000005cc594] dump_header+0x5c/0x1e4 [271641.879188] [c00000037540f7e0] [c0000000005cb464] oom_kill_process+0x324/0x3b0 [271641.879192] [c00000037540f860] [c0000000005cbe48] out_of_memory+0x118/0x420 [271641.879196] [c00000037540f8f0] [c00000000070d8ec] mem_cgroup_out_of_memory+0x18c/0x1b0 [271641.879200] [c00000037540f990] [c000000000713888] try_charge_memcg+0x598/0x890 [271641.879204] [c00000037540fa70] [c000000000713dbc] charge_memcg+0x5c/0x110 [271641.879207] [c00000037540faa0] [c0000000007159f8] __mem_cgroup_charge+0x48/0x120 [271641.879211] [c00000037540fae0] [c000000000641914] alloc_anon_folio+0x2b4/0x5a0 [271641.879215] [c00000037540fb60] [c000000000641d58] do_anonymous_page+0x158/0x6b0 [271641.879218] [c00000037540fbd0] [c000000000642f8c] __handle_mm_fault+0x4bc/0x910 [271641.879221] [c00000037540fcf0] [c000000000643500] handle_mm_fault+0x120/0x3c0 [271641.879224] [c00000037540fd40] [c00000000014bba0] ___do_page_fault+0x1c0/0x980 [271641.879228] [c00000037540fdf0] [c00000000014c44c] hash__do_page_fault+0x2c/0xc0 [271641.879232] [c00000037540fe20] [c0000000001565d8] do_hash_fault+0x128/0x1d0 [271641.879236] [c00000037540fe50] [c000000000008be0] data_access_common_virt+0x210/0x220 [271641.879548] Tasks state (memory values in pages): ... [271641.879550] [ pid ] uid tgid total_vm rss rss_anon rss_file rss_shmem pgtables_bytes swapents oom_score_adj name [271641.879555] [ 177372] 0 177372 571 0 0 0 0 51200 96 0 test_zswap [271641.879562] oom-kill:constraint=CONSTRAINT_MEMCG,nodemask=(null),cpuset=/,mems_allowed=0,oom_memcg=/no_zswap_test,task_memcg=/no_zswap_test,task=test_zswap,pid=177372,uid=0 [271641.879578] Memory cgroup out of memory: Killed process 177372 (test_zswap) total-vm:36544kB, anon-rss:0kB, file-rss:0kB, shmem-rss:0kB, UID:0 pgtables:50kB oom_score_adj:0 Link: https://lore.kernel.org/20260424040059.12940-3-li.wang@linux.dev Signed-off-by: Li Wang <li.wang@linux.dev> Acked-by: Yosry Ahmed <yosry@kernel.org> Acked-by: Nhat Pham <nphamcs@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Jiayuan Chen <jiayuan.chen@linux.dev> Cc: Waiman Long <longman@redhat.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Li Wang
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9f40c3cdf0 |
selftests/cgroup: skip test_zswap if zswap is globally disabled
Patch series "selftests/cgroup: improve zswap tests robustness and support large page sizes", v7. This patchset aims to fix various spurious failures and improve the overall robustness of the cgroup zswap selftests. The primary motivation is to make the tests compatible with architectures that use non-4K page sizes (such as 64K on ppc64le and arm64). Currently, the tests rely heavily on hardcoded 4K page sizes and fixed memory limits. On 64K page size systems, these hardcoded values lead to sub-page granularity accesses, incorrect page count calculations, and insufficient memory pressure to trigger zswap writeback, ultimately causing the tests to fail. Additionally, this series addresses OOM kills occurring in test_swapin_nozswap by dynamically scaling memory limits, and prevents spurious test failures when zswap is built into the kernel but globally disabled. This patch (of 8): test_zswap currently only checks whether zswap is present by testing /sys/module/zswap. This misses the runtime global state exposed in /sys/module/zswap/parameters/enabled. When zswap is built/loaded but globally disabled, the zswap cgroup selftests run in an invalid environment and may fail spuriously. Check the runtime enabled state before running the tests: - skip if zswap is not configured, - fail if the enabled knob cannot be read, - skip if zswap is globally disabled. Also print a hint in the skip message on how to enable zswap. Link: https://lore.kernel.org/20260424040059.12940-1-li.wang@linux.dev Link: https://lore.kernel.org/20260424040059.12940-2-li.wang@linux.dev Signed-off-by: Li Wang <li.wang@linux.dev> Acked-by: Yosry Ahmed <yosry@kernel.org> Acked-by: Nhat Pham <nphamcs@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Jiayuan Chen <jiayuan.chen@linux.dev> Cc: Waiman Long <longman@redhat.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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SeongJae Park
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8d21446a6c |
selftests/damon/sysfs.py: test failed region quota charge ratio
Extend sysfs.py DAMON selftest to setup DAMOS action failed region quota charge ratio and assert the setup is made into DAMON internal state. Link: https://lore.kernel.org/20260428013402.115171-12-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Brendan Higgins <brendan.higgins@linux.dev> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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SeongJae Park
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bcd8d68c6b |
selftests/damon/drgn_dump_damon_status: support failed region quota charge ratio
Extend drgn_dump_damon_status.py to dump DAMON internal state for DAMOS action failed regions quota charge ratio, to be able to show if the internal state for the feature is working, with future DAMON selftests. Link: https://lore.kernel.org/20260428013402.115171-11-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Brendan Higgins <brendan.higgins@linux.dev> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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SeongJae Park
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588f08518f |
selftests/damon/_damon_sysfs: support failed region quota charge ratio
Extend _damon_sysfs.py for DAMOS action failed regions quota charge ratio setup, so that we can add kselftest for the new feature. Link: https://lore.kernel.org/20260428013402.115171-10-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Brendan Higgins <brendan.higgins@linux.dev> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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SeongJae Park
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0a605b4b67 |
mm/damon/tests/core-kunit: test fail_charge_{num,denom} committing
Extend damos_test_commit_quotas() kunit test to ensure
damos_commit_quota() handles fail_charge_{num,denom} parameters.
Link: https://lore.kernel.org/20260428013402.115171-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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SeongJae Park
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1d6b8e92da |
Docs/ABI/damon: document fail_charge_{num,denom}
Update DAMON ABI document for the DAMOS action failed regions quota charge ratio control sysfs files. Link: https://lore.kernel.org/20260428013402.115171-8-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Brendan Higgins <brendan.higgins@linux.dev> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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SeongJae Park
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59ebdeedb5 |
Docs/admin-guide/mm/damon/usage: document fail_charge_{num,denom} files
Update DAMON usage document for the DAMOS action failed regions quota charge ratio control sysfs files. Link: https://lore.kernel.org/20260428013402.115171-7-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Brendan Higgins <brendan.higgins@linux.dev> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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SeongJae Park
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776270536d |
Docs/mm/damon/design: document fail_charge_{num,denom}
Update DAMON design document for the DAMOS action failed region quota charge ratio. Link: https://lore.kernel.org/20260428013402.115171-6-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Brendan Higgins <brendan.higgins@linux.dev> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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SeongJae Park
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fad1124120 |
mm/damon/sysfs-schemes: implement fail_charge_{num,denom} files
Implement the user-space ABI for the DAMOS action failed region quota-charge ratio setup. For this, add two new sysfs files under the DAMON sysfs interface for DAMOS quotas. Names of the files are fail_charge_num and fail_charge_denom, and work for reading and setting the numerator and denominator of the failed regions charge ratio. Link: https://lore.kernel.org/20260428013402.115171-5-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Brendan Higgins <brendan.higgins@linux.dev> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |