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authorMichal Hocko <mhocko@suse.cz>2012-12-12 13:52:23 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-12 17:38:35 -0800
commitc95d26c2ffd3931123d6a7a2489530ccbd36da7a (patch)
treead54b115b525c7956f85c2b0105bff055036e0e8
parent220f2ac91353dd8b239b70c4b4cf1615b80c1ff5 (diff)
memcg: do not check for mm in __mem_cgroup_count_vm_event
The mm given to __mem_cgroup_count_vm_event() cannot be NULL because the function is either called from the page fault path or vma->vm_mm is used. So the check can be dropped. The check was introduced by commit 456f998ec817 ("memcg: add the pagefault count into memcg stats") because the originally proposed patch used current->mm for shmem but this has been changed to vma->vm_mm later on without the check being removed (thanks to Hugh for this recollection). Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Ying Han <yinghan@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memcontrol.c3
1 files changed, 0 insertions, 3 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7f0e3571df7e..6c055929c8cc 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1021,9 +1021,6 @@ void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
{
struct mem_cgroup *memcg;
- if (!mm)
- return;
-
rcu_read_lock();
memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
if (unlikely(!memcg))