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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 /mm
parent220f2ac91353dd8b239b70c4b4cf1615b80c1ff5 (diff)
downloadlinux-c95d26c2ffd3931123d6a7a2489530ccbd36da7a.tar.gz
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>
Diffstat (limited to 'mm')
-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))