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authorMuchun Song <songmuchun@bytedance.com>2021-02-24 12:04:22 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-24 13:38:30 -0800
commit1685bde6b9af55923180a76152036c7fb7176db0 (patch)
tree611edd8bd93c5ef712ec0b18f6c79b34fd4ca75d /mm/memcontrol.c
parentcae3af62b33aa931427a0f211e04347b22180b36 (diff)
mm: memcontrol: fix get_active_memcg return value
We use a global percpu int_active_memcg variable to store the remote memcg when we are in the interrupt context. But get_active_memcg always return the current->active_memcg or root_mem_cgroup. The remote memcg (set in the interrupt context) is ignored. This is not what we want. So fix it. Link: https://lkml.kernel.org/r/20210223091101.42150-1-songmuchun@bytedance.com Fixes: 37d5985c003d ("mm: kmem: prepare remote memcg charging infra for interrupt contexts") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Roman Gushchin <guro@fb.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c10
1 files changed, 3 insertions, 7 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2db2aeac8a9e..845eec01ef9d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1061,13 +1061,9 @@ static __always_inline struct mem_cgroup *get_active_memcg(void)
rcu_read_lock();
memcg = active_memcg();
- if (memcg) {
- /* current->active_memcg must hold a ref. */
- if (WARN_ON_ONCE(!css_tryget(&memcg->css)))
- memcg = root_mem_cgroup;
- else
- memcg = current->active_memcg;
- }
+ /* remote memcg must hold a ref. */
+ if (memcg && WARN_ON_ONCE(!css_tryget(&memcg->css)))
+ memcg = root_mem_cgroup;
rcu_read_unlock();
return memcg;