From 190409caaf7e3eee6926943488e486590efe6fde Mon Sep 17 00:00:00 2001
From: Yosry Ahmed <yosryahmed@google.com>
Date: Fri, 21 Apr 2023 17:40:17 +0000
Subject: [PATCH] memcg: flush stats non-atomically in mem_cgroup_wb_stats()
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The previous patch moved the wb_over_bg_thresh()->mem_cgroup_wb_stats()
code path in wb_writeback() outside the lock section.  We no longer need
to flush the stats atomically.  Flush the stats non-atomically.

Link: https://lkml.kernel.org/r/20230421174020.2994750-3-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/memcontrol.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a05c53ab52381..929162c5f45f9 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4656,11 +4656,7 @@ 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;
 
-	/*
-	 * wb_writeback() takes a spinlock and calls
-	 * wb_over_bg_thresh()->mem_cgroup_wb_stats(). Do not sleep.
-	 */
-	mem_cgroup_flush_stats_atomic();
+	mem_cgroup_flush_stats();
 
 	*pdirty = memcg_page_state(memcg, NR_FILE_DIRTY);
 	*pwriteback = memcg_page_state(memcg, NR_WRITEBACK);
-- 
2.30.2