From 03583f1a631c0511dfd2f16e716d5b40f675de5a Mon Sep 17 00:00:00 2001
From: Johannes Weiner <hannes@cmpxchg.org>
Date: Mon, 7 Apr 2014 15:37:42 -0700
Subject: [PATCH] memcg: remove unnecessary !mm check from
try_get_mem_cgroup_from_mm()
Users pass either a mm that has been established under task lock, or use
a verified current->mm, which means the task can't be exiting.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/memcontrol.c | 7 -------
1 file changed, 7 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 8d6cedd16f8d..c3b674f9774f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1075,13 +1075,6 @@ struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
{
struct mem_cgroup *memcg = NULL;
- if (!mm)
- return NULL;
- /*
- * Because we have no locks, mm->owner's may be being moved to other
- * cgroup. We use css_tryget() here even if this looks
- * pessimistic (rather than adding locks here).
- */
rcu_read_lock();
do {
memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
--
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