[merged mm-stable] mm-ratelimit-stat-flush-from-workingset-shrinker.patch removed from -mm tree

[merged mm-stable] mm-ratelimit-stat-flush-from-workingset-shrinker.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm: ratelimit stat flush from workingset shrinker
has been removed from the -mm tree.  Its filename was
     mm-ratelimit-stat-flush-from-workingset-shrinker.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@google.com>
Subject: mm: ratelimit stat flush from workingset shrinker
Date: Thu, 28 Dec 2023 07:30:55 +0000

One of our workloads (Postgres 14 + sysbench OLTP) regressed on newer
upstream kernel and on further investigation, it seems like the cause is
the always synchronous rstat flush in the count_shadow_nodes() added by
the commit f82e6bf9bb9b ("mm: memcg: use rstat for non-hierarchical
stats").  On further inspection it seems like we don't really need
accurate stats in this function as it was already approximating the amount
of appropriate shadow entries to keep for maintaining the refault
information.  Since there is already 2 sec periodic rstat flush, we don't
need exact stats here.  Let's ratelimit the rstat flush in this code path.

Link: https://lkml.kernel.org/r/20231228073055.4046430-1-shakeelb@google.com
Fixes: f82e6bf9bb9b ("mm: memcg: use rstat for non-hierarchical stats")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/workingset.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/workingset.c~mm-ratelimit-stat-flush-from-workingset-shrinker
+++ a/mm/workingset.c
@@ -680,7 +680,7 @@ static unsigned long count_shadow_nodes(
 		struct lruvec *lruvec;
 		int i;
 
-		mem_cgroup_flush_stats(sc->memcg);
+		mem_cgroup_flush_stats_ratelimited(sc->memcg);
 		lruvec = mem_cgroup_lruvec(sc->memcg, NODE_DATA(sc->nid));
 		for (pages = 0, i = 0; i < NR_LRU_LISTS; i++)
 			pages += lruvec_page_state_local(lruvec,
_

Patches currently in -mm which might be from shakeelb@google.com are