[PATCH] mm/memcg: remove redundant checking on root memcg

[Wanpeng Li <liwanp-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>]

Function __mem_cgroup_cancel_local_charge is only called by
mem_cgroup_move_parent. For this case, root memcg has been
checked by mem_cgroup_move_parent. So we needn't check that
again in function __mem_cgroup_cancel_local_charge and just
remove the check in function __mem_cgroup_cancel_local_charge.

Signed-off-by: Wanpeng Li <liwanp-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
---
 mm/memcontrol.c |    3 ---
 1 files changed, 0 insertions(+), 3 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6392c0a..d346347 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2404,9 +2404,6 @@ static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg,
 {
 	unsigned long bytes = nr_pages * PAGE_SIZE;
 
-	if (mem_cgroup_is_root(memcg))
-		return;
-
 	res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes);
 	if (do_swap_account)
 		res_counter_uncharge_until(&memcg->memsw,
-- 
1.7.5.4