From c95d26c2ffd3931123d6a7a2489530ccbd36da7a Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Wed, 12 Dec 2012 13:52:23 -0800 Subject: [PATCH] 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 Cc: Hugh Dickins Cc: Ying Han Cc: David Rientjes Cc: Johannes Weiner Cc: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 7f0e357..6c05592 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)) -- 2.7.4