Commit ae3abae6 authored by Daisuke Nishimura's avatar Daisuke Nishimura Committed by Linus Torvalds
Browse files

memcg: fix mem_cgroup_shrink_usage() 



Current mem_cgroup_shrink_usage() has two problems.

1. It doesn't call mem_cgroup_out_of_memory and doesn't update
   last_oom_jiffies, so pagefault_out_of_memory invokes global OOM.

2. Considering hierarchy, shrinking has to be done from the
   mem_over_limit, not from the memcg which the page would be charged to.

mem_cgroup_try_charge_swapin() does all of these things properly, so we
use it and call cancel_charge_swapin when it succeeded.

The name of "shrink_usage" is not appropriate for this behavior, so we
change it too.

Signed-off-by: default avatarDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.cn>
Cc: Paul Menage <menage@google.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 08161786

include/linux/memcontrol.h

+2 −2
Original line number Diff line number Diff line
@@ -56,7 +56,7 @@ extern void mem_cgroup_move_lists(struct page *page, 
				  enum lru_list from, enum lru_list to);

extern void mem_cgroup_uncharge_page(struct page *page);

extern void mem_cgroup_uncharge_cache_page(struct page *page);

extern int mem_cgroup_shrink_usage(struct page *page,

extern int mem_cgroup_shmem_charge_fallback(struct page *page,

			struct mm_struct *mm, gfp_t gfp_mask);



extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
@@ -155,7 +155,7 @@ static inline void mem_cgroup_uncharge_cache_page(struct page *page) 
{

}



static inline int mem_cgroup_shrink_usage(struct page *page,

static inline int mem_cgroup_shmem_charge_fallback(struct page *page,

			struct mm_struct *mm, gfp_t gfp_mask)

{

	return 0;

mm/memcontrol.c

+12 −21
Original line number Diff line number Diff line
@@ -1617,37 +1617,28 @@ void mem_cgroup_end_migration(struct mem_cgroup *mem, 
}



/*

 * A call to try to shrink memory usage under specified resource controller.

 * This is typically used for page reclaiming for shmem for reducing side

 * effect of page allocation from shmem, which is used by some mem_cgroup.

 */

int mem_cgroup_shrink_usage(struct page *page,

 * A call to try to shrink memory usage on charge failure at shmem's swapin.

 * Calling hierarchical_reclaim is not enough because we should update

 * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM.

 * Moreover considering hierarchy, we should reclaim from the mem_over_limit,

 * not from the memcg which this page would be charged to.

 * try_charge_swapin does all of these works properly.

 */

int mem_cgroup_shmem_charge_fallback(struct page *page,

			    struct mm_struct *mm,

			    gfp_t gfp_mask)

{

	struct mem_cgroup *mem = NULL;

	int progress = 0;

	int retry = MEM_CGROUP_RECLAIM_RETRIES;

	int ret;



	if (mem_cgroup_disabled())

		return 0;

	if (page)

		mem = try_get_mem_cgroup_from_swapcache(page);

	if (!mem && mm)

		mem = try_get_mem_cgroup_from_mm(mm);

	if (unlikely(!mem))

		return 0;



	do {

		progress = mem_cgroup_hierarchical_reclaim(mem,

					gfp_mask, true, false);

		progress += mem_cgroup_check_under_limit(mem);

	} while (!progress && --retry);

	ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);

	if (!ret)

		mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */



	css_put(&mem->css);

	if (!retry)

		return -ENOMEM;

	return 0;

	return ret;

}



static DEFINE_MUTEX(set_limit_mutex);

mm/shmem.c

+6 −2
Original line number Diff line number Diff line
@@ -1340,8 +1340,12 @@ repeat: 
			shmem_swp_unmap(entry);

			spin_unlock(&info->lock);

			if (error == -ENOMEM) {

				/* allow reclaim from this memory cgroup */

				error = mem_cgroup_shrink_usage(swappage,

				/*

				 * reclaim from proper memory cgroup and

				 * call memcg's OOM if needed.

				 */

				error = mem_cgroup_shmem_charge_fallback(

								swappage,

								current->mm,

								gfp);

				if (error) {

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