memcg: avoid unnecessary system-wide-oom-killer

Current mmtom has new oom function as pagefault_out_of_memory().  It's
added for select bad process rathar than killing current.

When memcg hit limit and calls OOM at page_fault, this handler called and
system-wide-oom handling happens.  (means kernel panics if panic_on_oom is
true....)

To avoid overkill, check memcg's recent behavior before starting
system-wide-oom.

And this patch also fixes to guarantee "don't accnout against process with
TIF_MEMDIE".  This is necessary for smooth OOM.

[akpm@linux-foundation.org: build fix]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Jan Blunck <jblunck@suse.de>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 2de6504e01fb..2fdd1380bf0a 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -102,6 +102,8 @@ static inline bool mem_cgroup_disabled(void)
 	return false;
 }
 
+extern bool mem_cgroup_oom_called(struct task_struct *task);
+
 #else /* CONFIG_CGROUP_MEM_RES_CTLR */
 struct mem_cgroup;
 
@@ -234,6 +236,11 @@ static inline bool mem_cgroup_disabled(void)
 {
 	return true;
 }
+
+static inline bool mem_cgroup_oom_called(struct task_struct *task)
+{
+	return false;
+}
 #endif /* CONFIG_CGROUP_MEM_CONT */
 
 #endif /* _LINUX_MEMCONTROL_H */