Commit c9b0ed51 authored by KAMEZAWA Hiroyuki's avatar KAMEZAWA Hiroyuki Committed by Linus Torvalds
Browse files

memcg: helper function for relcaim from shmem. 



A new call, mem_cgroup_shrink_usage() is added for shmem handling and
relacing non-standard usage of mem_cgroup_charge/uncharge.

Now, shmem calls mem_cgroup_charge() just for reclaim some pages from
mem_cgroup.  In general, shmem is used by some process group and not for
global resource (like file caches).  So, it's reasonable to reclaim pages
from mem_cgroup where shmem is mainly used.

[hugh@veritas.com: shmem_getpage release page sooner]
[hugh@veritas.com: mem_cgroup_shrink_usage css_put]
Signed-off-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Paul Menage <menage@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 69029cd5

include/linux/memcontrol.h

+7 −0
Original line number Diff line number Diff line
@@ -37,6 +37,8 @@ extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, 
extern void mem_cgroup_uncharge_page(struct page *page);

extern void mem_cgroup_uncharge_cache_page(struct page *page);

extern void mem_cgroup_move_lists(struct page *page, bool active);

extern int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask);



extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,

					struct list_head *dst,

					unsigned long *scanned, int order,
@@ -102,6 +104,11 @@ static inline void mem_cgroup_uncharge_cache_page(struct page *page) 
{

}



static inline int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)

{

	return 0;

}



static inline void mem_cgroup_move_lists(struct page *page, bool active)

{

}

mm/memcontrol.c

+26 −0
Original line number Diff line number Diff line
@@ -780,6 +780,32 @@ void mem_cgroup_end_migration(struct page *newpage) 
		mem_cgroup_uncharge_page(newpage);

}



/*

 * 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 mm_struct *mm, gfp_t gfp_mask)

{

	struct mem_cgroup *mem;

	int progress = 0;

	int retry = MEM_CGROUP_RECLAIM_RETRIES;



	rcu_read_lock();

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

	css_get(&mem->css);

	rcu_read_unlock();



	do {

		progress = try_to_free_mem_cgroup_pages(mem, gfp_mask);

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



	css_put(&mem->css);

	if (!retry)

		return -ENOMEM;

	return 0;

}



/*

 * This routine traverse page_cgroup in given list and drop them all.

 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.

mm/shmem.c

+4 −7
Original line number Diff line number Diff line
@@ -1315,17 +1315,14 @@ repeat: 
			shmem_swp_unmap(entry);

			spin_unlock(&info->lock);

			unlock_page(swappage);

			page_cache_release(swappage);

			if (error == -ENOMEM) {

				/* allow reclaim from this memory cgroup */

				error = mem_cgroup_cache_charge(swappage,

					current->mm, gfp & ~__GFP_HIGHMEM);

				if (error) {

					page_cache_release(swappage);

				error = mem_cgroup_shrink_usage(current->mm,

								gfp);

				if (error)

					goto failed;

			}

				mem_cgroup_uncharge_cache_page(swappage);

			}

			page_cache_release(swappage);

			goto repeat;

		}

	} else if (sgp == SGP_READ && !filepage) {

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