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| author | Jianlin Shi <shijianlin11@foxmail.com> | 2026-06-04 12:01:38 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-06-21 11:31:29 -0700 |
| commit | 874611d193f29666184bcbcb8638eff87d63d019 (patch) | |
| tree | c1db0efcdae245c0cca79066b15ca16eb31e4c99 | |
| parent | b35a8205a3cc87c1fcfb5d2ba25f49ea9342cbc7 (diff) | |
| download | linux-next-874611d193f29666184bcbcb8638eff87d63d019.tar.gz linux-next-874611d193f29666184bcbcb8638eff87d63d019.zip | |
mm/page_alloc: only update NUMA min ratios on sysctl write
The sysctl handlers for min_unmapped_ratio and min_slab_ratio invoke
setup_min_unmapped_ratio() and setup_min_slab_ratio() unconditionally
after proc_dointvec_minmax(), even for read operations.
These setup functions first zero all per-NUMA node thresholds
(min_unmapped_pages and min_slab_pages) before recalculating them.
Reading /proc sysctl entries therefore temporarily resets node reclaim
thresholds to zero, which may disturb the behavior of __node_reclaim() and
node_reclaim() during the recomputation.
Fix this by only calling the setup functions when the sysctl is actually
written (write == 1), matching the behavior of existing sysctl handlers
like min_free_kbytes and watermark_scale_factor.
This only affects systems with CONFIG_NUMA.
Link: https://lore.kernel.org/tencent_5891052AF9A4C2D490A62F478D446F74AB09@qq.com
Signed-off-by: Jianlin Shi <shijianlin11@foxmail.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/page_alloc.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 81a9d4d1e6c0..ee902a468c2f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6653,7 +6653,8 @@ static int sysctl_min_unmapped_ratio_sysctl_handler(const struct ctl_table *tabl if (rc) return rc; - setup_min_unmapped_ratio(); + if (write) + setup_min_unmapped_ratio(); return 0; } @@ -6680,7 +6681,8 @@ static int sysctl_min_slab_ratio_sysctl_handler(const struct ctl_table *table, i if (rc) return rc; - setup_min_slab_ratio(); + if (write) + setup_min_slab_ratio(); return 0; } |