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From:   Lu Jialin <lujialin4@huawei.com>
To:     Johannes Weiner <hannes@cmpxchg.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@kernel.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Shakeel Butt <shakeelb@google.com>,
        Muchun Song <songmuchun@bytedance.com>
CC:     Lu Jialin <lujialin4@huawei.com>, <cgroups@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>
Subject: [PATCH] mm/memcontrol.c: drains percpu charge caches in memory.reclaim
Date:   Thu, 10 Nov 2022 14:53:16 +0800
Message-ID: <20221110065316.67204-1-lujialin4@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

When user use memory.reclaim to reclaim memory, after drain percpu lru
caches, drain percpu charge caches for given memcg stock in the hope
of introducing more evictable pages.

Signed-off-by: Lu Jialin <lujialin4@huawei.com>
---
 mm/memcontrol.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2d8549ae1b30..768091cc6a9a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6593,10 +6593,13 @@ static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf,
 		/*
 		 * This is the final attempt, drain percpu lru caches in the
 		 * hope of introducing more evictable pages for
-		 * try_to_free_mem_cgroup_pages().
+		 * try_to_free_mem_cgroup_pages(). Also, drain all percpu
+		 * charge caches for given memcg.
 		 */
-		if (!nr_retries)
+		if (!nr_retries) {
 			lru_add_drain_all();
+			drain_all_stock(memcg);
+		}
 
 		reclaimed = try_to_free_mem_cgroup_pages(memcg,
 						nr_to_reclaim - nr_reclaimed,
-- 
2.17.1