The quilt patch titled
Subject: mm: writeback: ratelimit stat flush from mem_cgroup_wb_stats
has been removed from the -mm tree. Its filename was
mm-writeback-ratelimit-stat-flush-from-mem_cgroup_wb_stats.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Shakeel Butt <shakeelb@xxxxxxxxxx>
Subject: mm: writeback: ratelimit stat flush from mem_cgroup_wb_stats
Date: Thu, 18 Jan 2024 18:42:35 +0000
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@xxxxxxxxxx
Fixes: 2d146aa3aa84 ("mm: memcontrol: switch to rstat")
Signed-off-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/memcontrol.c~mm-writeback-ratelimit-stat-flush-from-mem_cgroup_wb_stats
+++ a/mm/memcontrol.c
@@ -4800,7 +4800,7 @@ void mem_cgroup_wb_stats(struct bdi_writ
struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
struct mem_cgroup *parent;
- mem_cgroup_flush_stats(memcg);
+ mem_cgroup_flush_stats_ratelimited(memcg);
*pdirty = memcg_page_state(memcg, NR_FILE_DIRTY);
*pwriteback = memcg_page_state(memcg, NR_WRITEBACK);
_
Patches currently in -mm which might be from shakeelb@xxxxxxxxxx are
