[PATCH] mm/memcontrol: Skip root memcg in memcg_memory_event_mm

[Haifeng Xu]

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@xxxxxxxxxx>
---
 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