The quilt patch titled
Subject: memcg: do not modify rstat tree for zero updates
has been removed from the -mm tree. Its filename was
memcg-do-not-modify-rstat-tree-for-zero-updates.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: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Subject: memcg: do not modify rstat tree for zero updates
Date: Thu, 30 Mar 2023 19:18:01 +0000
In some situations, we may end up calling memcg_rstat_updated() with a
value of 0, which means the stat was not actually updated. An example is
if we fail to reclaim any pages in shrink_folio_list().
Do not add the cgroup to the rstat updated tree in this case, to avoid
unnecessarily flushing it.
Link: https://lkml.kernel.org/r/20230330191801.1967435-9-yosryahmed@xxxxxxxxxx
Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Acked-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Reviewed-by: Michal Koutný <mkoutny@xxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Josef Bacik <josef@xxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Vasily Averin <vasily.averin@xxxxxxxxx>
Cc: Zefan Li <lizefan.x@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 3 +++
1 file changed, 3 insertions(+)
--- a/mm/memcontrol.c~memcg-do-not-modify-rstat-tree-for-zero-updates
+++ a/mm/memcontrol.c
@@ -619,6 +619,9 @@ static inline void memcg_rstat_updated(s
{
unsigned int x;
+ if (!val)
+ return;
+
cgroup_rstat_updated(memcg->css.cgroup, smp_processor_id());
x = __this_cpu_add_return(stats_updates, abs(val));
_
Patches currently in -mm which might be from yosryahmed@xxxxxxxxxx are
memcg-page_cgroup_ino-get-memcg-from-the-pages-folio.patch
mm-vmscan-ignore-non-lru-based-reclaim-in-memcg-reclaim.patch
mm-vmscan-move-set_task_reclaim_state-near-flush_reclaim_state.patch
mm-vmscan-refactor-updating-current-reclaim_state.patch
