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From:   Haifeng Xu <haifeng.xu@shopee.com>
To:     akpm@linux-foundation.org
Cc:     shakeelb@google.com, roman.gushchin@linux.dev,
        songmuchun@bytedance.com, hannes@cmpxchg.org, vbabka@suse.cz,
        willy@infradead.org, vasily.averin@linux.dev,
        linux-kernel@vger.kernel.org, Haifeng Xu <haifeng.xu@shopee.com>
Subject: [PATCH] mm/memcontrol: Skip root memcg in memcg_memory_event_mm
Date:   Thu, 15 Dec 2022 09:19:07 +0000
Message-Id: <20221215091907.763801-1-haifeng.xu@shopee.com>
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The memory events aren't supported on root cgroup, so there is no need
to account MEMCG_OOM_KILL on root memcg.

Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com>
---
 include/linux/memcontrol.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 567f12323f55..09f75161a3bc 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1142,7 +1142,7 @@ static inline void memcg_memory_event_mm(struct mm_struct *mm,
 
 	rcu_read_lock();
 	memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
-	if (likely(memcg))
+	if (likely(memcg && !mem_cgroup_is_root(memcg)))
 		memcg_memory_event(memcg, event);
 	rcu_read_unlock();
 }
-- 
2.25.1