[PATCH] mm: memcontrol: fix percpu vmstats and vmevents flush

From: Shakeel Butt <shakeelb@google.com>
To: Roman Gushchin <guro@fb.com>
Cc: linux-mm@kvack.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org, Shakeel Butt <shakeelb@google.com>,
	Michal Hocko <mhocko@suse.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Vladimir Davydov <vdavydov.dev@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	stable@vger.kernel.org
Subject: [PATCH] mm: memcontrol: fix percpu vmstats and vmevents flush
Date: Thu, 29 Aug 2019 13:31:10 -0700	[thread overview]
Message-ID: <20190829203110.129263-1-shakeelb@google.com> (raw)

Instead of using raw_cpu_read() use per_cpu() to read the actual data of
the corresponding cpu otherwise we will be reading the data of the
current cpu for the number of online CPUs.

Fixes: bb65f89b7d3d ("mm: memcontrol: flush percpu vmevents before releasing memcg")
Fixes: c350a99ea2b1 ("mm: memcontrol: flush percpu vmstats before releasing memcg")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org>
---

Note: The buggy patches were marked for stable therefore adding Cc to
stable.

 mm/memcontrol.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 26e2999af608..f4e60ee8b845 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3271,7 +3271,7 @@ static void memcg_flush_percpu_vmstats(struct mem_cgroup *memcg)
 
 	for_each_online_cpu(cpu)
 		for (i = 0; i < MEMCG_NR_STAT; i++)
-			stat[i] += raw_cpu_read(memcg->vmstats_percpu->stat[i]);
+			stat[i] += per_cpu(memcg->vmstats_percpu->stat[i], cpu);
 
 	for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
 		for (i = 0; i < MEMCG_NR_STAT; i++)
@@ -3286,8 +3286,8 @@ static void memcg_flush_percpu_vmstats(struct mem_cgroup *memcg)
 
 		for_each_online_cpu(cpu)
 			for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
-				stat[i] += raw_cpu_read(
-					pn->lruvec_stat_cpu->count[i]);
+				stat[i] += per_cpu(
+					pn->lruvec_stat_cpu->count[i], cpu);
 
 		for (pi = pn; pi; pi = parent_nodeinfo(pi, node))
 			for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
@@ -3306,8 +3306,8 @@ static void memcg_flush_percpu_vmevents(struct mem_cgroup *memcg)
 
 	for_each_online_cpu(cpu)
 		for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
-			events[i] += raw_cpu_read(
-				memcg->vmstats_percpu->events[i]);
+			events[i] += per_cpu(memcg->vmstats_percpu->events[i],
+					     cpu);
 
 	for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
 		for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
-- 
2.23.0.187.g17f5b7556c-goog

