memcg: hierarchy avoid unnecessary reclaim
If hierarchy is not used, no tree-walk is necessary.
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 964a700..9b4993e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -606,6 +606,8 @@
ret = try_to_free_mem_cgroup_pages(root_mem, gfp_mask, noswap);
if (mem_cgroup_check_under_limit(root_mem))
return 0;
+ if (!root_mem->use_hierarchy)
+ return ret;
next_mem = mem_cgroup_get_first_node(root_mem);