From d12c60f64cf8c768fddfd848eaf7ee57a13f18b1 Mon Sep 17 00:00:00 2001
From: Junaid Shahid <junaids@google.com>
Date: Thu, 7 Jun 2018 17:07:31 -0700
Subject: mm: memcontrol: drain memcg stock on force_empty

The per-cpu memcg stock can retain a charge of upto 32 pages.  On a
machine with large number of cpus, this can amount to a decent amount of
memory.  Additionally force_empty interface might be triggering unneeded
memcg reclaims.

Link: http://lkml.kernel.org/r/20180507201651.165879-1-shakeelb@google.com
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/memcontrol.c | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'mm')

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 18dcdac0b158..e6de0d6a3a8d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2610,6 +2610,9 @@ static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
 
 	/* we call try-to-free pages for make this cgroup empty */
 	lru_add_drain_all();
+
+	drain_all_stock(memcg);
+
 	/* try to free all pages in this cgroup */
 	while (nr_retries && page_counter_read(&memcg->memory)) {
 		int progress;
-- 
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