Commit a636b327 authored by KAMEZAWA Hiroyuki's avatar KAMEZAWA Hiroyuki Committed by Linus Torvalds
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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: default avatarKAMEZAWA 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2e4d4091

include/linux/memcontrol.h

+7 −0
Original line number Diff line number Diff line
@@ -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 */

mm/memcontrol.c

+29 −4
Original line number Diff line number Diff line
@@ -153,7 +153,7 @@ struct mem_cgroup { 
	 * Should the accounting and control be hierarchical, per subtree?

	 */

	bool use_hierarchy;



	unsigned long	last_oom_jiffies;

	int		obsolete;

	atomic_t	refcnt;

	/*
@@ -615,6 +615,22 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem, 
	return ret;

}



bool mem_cgroup_oom_called(struct task_struct *task)

{

	bool ret = false;

	struct mem_cgroup *mem;

	struct mm_struct *mm;



	rcu_read_lock();

	mm = task->mm;

	if (!mm)

		mm = &init_mm;

	mem = mem_cgroup_from_task(rcu_dereference(mm->owner));

	if (mem && time_before(jiffies, mem->last_oom_jiffies + HZ/10))

		ret = true;

	rcu_read_unlock();

	return ret;

}

/*

 * Unlike exported interface, "oom" parameter is added. if oom==true,

 * oom-killer can be invoked.
@@ -626,6 +642,13 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, 
	struct mem_cgroup *mem, *mem_over_limit;

	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;

	struct res_counter *fail_res;



	if (unlikely(test_thread_flag(TIF_MEMDIE))) {

		/* Don't account this! */

		*memcg = NULL;

		return 0;

	}



	/*

	 * We always charge the cgroup the mm_struct belongs to.

	 * The mm_struct's mem_cgroup changes on task migration if the
@@ -694,8 +717,10 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, 
			continue;



		if (!nr_retries--) {

			if (oom)

			if (oom) {

				mem_cgroup_out_of_memory(mem, gfp_mask);

				mem->last_oom_jiffies = jiffies;

			}

			goto nomem;

		}

	}
@@ -832,7 +857,7 @@ static int mem_cgroup_move_parent(struct page_cgroup *pc, 




	ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);

	if (ret)

	if (ret || !parent)

		return ret;



	if (!get_page_unless_zero(page))
@@ -883,7 +908,7 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, 


	mem = memcg;

	ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);

	if (ret)

	if (ret || !mem)

		return ret;



	__mem_cgroup_commit_charge(mem, pc, ctype);

mm/oom_kill.c

+8 −0
Original line number Diff line number Diff line
@@ -560,6 +560,13 @@ void pagefault_out_of_memory(void) 
		/* Got some memory back in the last second. */

		return;



	/*

	 * If this is from memcg, oom-killer is already invoked.

	 * and not worth to go system-wide-oom.

	 */

	if (mem_cgroup_oom_called(current))

		goto rest_and_return;



	if (sysctl_panic_on_oom)

		panic("out of memory from page fault. panic_on_oom is selected.\n");
@@ -571,6 +578,7 @@ void pagefault_out_of_memory(void) 
	 * Give "p" a good chance of killing itself before we

	 * retry to allocate memory.

	 */

rest_and_return:

	if (!test_thread_flag(TIF_MEMDIE))

		schedule_timeout_uninterruptible(1);

}

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