[BUGFIX][PATCH 4/5] memcg: fix wrong check of noswap with softlimit

KAMEZAWA Hiroyuki
2011-06-13T03:18:06Z

>From 0a0358d300330a4ba86e39ea56ed63f1e4519dfd Mon Sep 17 00:00:00 2001
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Date: Mon, 13 Jun 2011 10:31:16 +0900
Subject: [PATCH 4/5] fix wrong check of noswap with softlimit

Hierarchical reclaim doesn't swap out if memsw and resource limits are
same (memsw_is_minimum == true) because we would hit mem+swap limit
anyway (during hard limit reclaim).
If it comes to the solft limit we shouldn't consider memsw_is_minimum at
all because it doesn't make much sense. Either the soft limit is bellow
the hard limit and then we cannot hit mem+swap limit or the direct
reclaim takes a precedence.

Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
---
mm/memcontrol.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ce05835..915c3f3 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1663,7 +1663,7 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;

/* If memsw_is_minimum==1, swap-out is of-no-use. */
- if (root_mem->memsw_is_minimum)
+ if (!check_soft && root_mem->memsw_is_minimum)
noswap = true;

while (1) {
--
1.7.4.1