From: Shakeel Butt <shakeelb@google.com> mainline inclusion from mainline-v6.9-rc1 commit d9b3ce8769e371554a669f262bbc61c02a40efcc category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IB0CT3 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ---------------------------------------------------------------------- One of our workloads (Postgres 14) has regressed when migrated from 5.10 to 6.1 upstream kernel. The regression can be reproduced by sysbench's oltp_write_only benchmark. It seems like the always on rstat flush in mem_cgroup_wb_stats() is causing the regression. So, rate limit that specific rstat flush. One potential consequence would be the dirty throttling might be decided on stale memcg stats. However from our benchmarks and production traffic we have not observed any change in the dirty throttling behavior of the application. Link: https://lkml.kernel.org/r/20240118184235.618164-1-shakeelb@google.com Fixes: 2d146aa3aa84 ("mm: memcontrol: switch to rstat") Signed-off-by: Shakeel Butt <shakeelb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Conflicts: mm/memcontrol.c [patch set:mm: memcg: restore subtree stats flushing was not merged, kabi is changed if merge this patchset] Signed-off-by: Chen Ridong <chenridong@huawei.com> --- mm/memcontrol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index cd9bd7dd149d..9bc081962934 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5398,7 +5398,7 @@ void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages, struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css); struct mem_cgroup *parent; - mem_cgroup_flush_stats(); + mem_cgroup_flush_stats_ratelimited(); *pdirty = memcg_page_state(memcg, NR_FILE_DIRTY); *pwriteback = memcg_page_state(memcg, NR_WRITEBACK); -- 2.34.1