memcg: fix wake up in oom wait queue
OOM-waitqueue should be waken up when oom_disable is canceled. This is a
fix for 3c11ecf448eff8f1 ("memcg: oom kill disable and oom status").
How to test:
Create a cgroup A...
1. set memory.limit and memory.memsw.limit to be small value
2. echo 1 > /cgroup/A/memory.oom_control, this disables oom-kill.
3. run a program which must cause OOM.
A program executed in 3 will sleep by oom_waiqueue in memcg. Then, how to
wake it up is problem.
1. echo 0 > /cgroup/A/memory.oom_control (enable OOM-killer)
2. echo big mem > /cgroup/A/memory.memsw.limit_in_bytes(allow more swap)
etc..
Without the patch, a task in slept can not be waken up.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.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 c6ece0a..20a8193 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1370,7 +1370,7 @@
static void memcg_oom_recover(struct mem_cgroup *mem)
{
- if (mem->oom_kill_disable && atomic_read(&mem->oom_lock))
+ if (atomic_read(&mem->oom_lock))
memcg_wakeup_oom(mem);
}
@@ -3781,6 +3781,8 @@
return -EINVAL;
}
mem->oom_kill_disable = val;
+ if (!val)
+ memcg_oom_recover(mem);
cgroup_unlock();
return 0;
}