linux-kernel - [PATCH 2/5] mm, memcg: narrow the scope of percpu_charge

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Message-ID: <20210729125755.16871-3-linmiaohe@huawei.com>
Date:   Thu, 29 Jul 2021 20:57:52 +0800
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     <hannes@...xchg.org>, <mhocko@...nel.org>,
        <vdavydov.dev@...il.com>, <akpm@...ux-foundation.org>
CC:     <shakeelb@...gle.com>, <guro@...com>, <willy@...radead.org>,
        <alexs@...nel.org>, <richard.weiyang@...il.com>,
        <songmuchun@...edance.com>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>, <cgroups@...r.kernel.org>,
        <linmiaohe@...wei.com>
Subject: [PATCH 2/5] mm, memcg: narrow the scope of percpu_charge_mutex

Since percpu_charge_mutex is only used inside drain_all_stock(), we can
narrow the scope of percpu_charge_mutex by moving it here.

Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
---
 mm/memcontrol.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6580c2381a3e..a03e24e57cd9 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2050,7 +2050,6 @@ struct memcg_stock_pcp {
 #define FLUSHING_CACHED_CHARGE	0
 };
 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
-static DEFINE_MUTEX(percpu_charge_mutex);
 
 #ifdef CONFIG_MEMCG_KMEM
 static void drain_obj_stock(struct obj_stock *stock);
@@ -2209,6 +2208,7 @@ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
  */
 static void drain_all_stock(struct mem_cgroup *root_memcg)
 {
+	static DEFINE_MUTEX(percpu_charge_mutex);
 	int cpu, curcpu;
 
 	/* If someone's already draining, avoid adding running more workers. */
-- 
2.23.0