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Commit bed7161a authored by Balbir Singh's avatar Balbir Singh Committed by Linus Torvalds
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Memory controller: make page_referenced() cgroup aware 



Make page_referenced() cgroup aware.  Without this patch, page_referenced()
can cause a page to be skipped while reclaiming pages.  This patch ensures
that other cgroups do not hold pages in a particular cgroup hostage.  It
is required to ensure that shared pages are freed from a cgroup when they
are not actively referenced from the cgroup that brought them in

Signed-off-by: default avatarBalbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Paul Menage <menage@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: David Rientjes <rientjes@google.com>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8697d331

include/linux/memcontrol.h

+6 −0
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, 
					int active);

extern void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask);

extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm);

extern struct mem_cgroup *mm_cgroup(struct mm_struct *mm);



static inline void mem_cgroup_uncharge_page(struct page *page)

{
@@ -93,6 +94,11 @@ static inline int mem_cgroup_cache_charge(struct page *page, 
	return 0;

}



static inline struct mem_cgroup *mm_cgroup(struct mm_struct *mm)

{

	return NULL;

}



#endif /* CONFIG_CGROUP_MEM_CONT */



#endif /* _LINUX_MEMCONTROL_H */

include/linux/rmap.h

+3 −2
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include <linux/slab.h>

#include <linux/mm.h>

#include <linux/spinlock.h>

#include <linux/memcontrol.h>



/*

 * The anon_vma heads a list of private "related" vmas, to scan if
@@ -86,7 +87,7 @@ static inline void page_dup_rmap(struct page *page, struct vm_area_struct *vma, 
/*

 * Called from mm/vmscan.c to handle paging out

 */

int page_referenced(struct page *, int is_locked);

int page_referenced(struct page *, int is_locked, struct mem_cgroup *cnt);

int try_to_unmap(struct page *, int ignore_refs);



/*
@@ -114,7 +115,7 @@ int page_mkclean(struct page *); 
#define anon_vma_prepare(vma)	(0)

#define anon_vma_link(vma)	do {} while (0)



#define page_referenced(page,l) TestClearPageReferenced(page)

#define page_referenced(page,l,cnt) TestClearPageReferenced(page)

#define try_to_unmap(page, refs) SWAP_FAIL



static inline int page_mkclean(struct page *page)

mm/memcontrol.c

+5 −0
Original line number Diff line number Diff line
@@ -110,6 +110,11 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) 
				struct mem_cgroup, css);

}



inline struct mem_cgroup *mm_cgroup(struct mm_struct *mm)

{

	return rcu_dereference(mm->mem_cgroup);

}



void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p)

{

	struct mem_cgroup *mem;

mm/rmap.c

+24 −6
Original line number Diff line number Diff line
@@ -302,7 +302,8 @@ out: 
	return referenced;

}



static int page_referenced_anon(struct page *page)

static int page_referenced_anon(struct page *page,

				struct mem_cgroup *mem_cont)

{

	unsigned int mapcount;

	struct anon_vma *anon_vma;
@@ -315,6 +316,13 @@ static int page_referenced_anon(struct page *page) 


	mapcount = page_mapcount(page);

	list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {

		/*

		 * If we are reclaiming on behalf of a cgroup, skip

		 * counting on behalf of references from different

		 * cgroups

		 */

		if (mem_cont && (mm_cgroup(vma->vm_mm) != mem_cont))

			continue;

		referenced += page_referenced_one(page, vma, &mapcount);

		if (!mapcount)

			break;
@@ -335,7 +343,8 @@ static int page_referenced_anon(struct page *page) 
 *

 * This function is only called from page_referenced for object-based pages.

 */

static int page_referenced_file(struct page *page)

static int page_referenced_file(struct page *page,

				struct mem_cgroup *mem_cont)

{

	unsigned int mapcount;

	struct address_space *mapping = page->mapping;
@@ -368,6 +377,13 @@ static int page_referenced_file(struct page *page) 
	mapcount = page_mapcount(page);



	vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {

		/*

		 * If we are reclaiming on behalf of a cgroup, skip

		 * counting on behalf of references from different

		 * cgroups

		 */

		if (mem_cont && (mm_cgroup(vma->vm_mm) != mem_cont))

			continue;

		if ((vma->vm_flags & (VM_LOCKED|VM_MAYSHARE))

				  == (VM_LOCKED|VM_MAYSHARE)) {

			referenced++;
@@ -390,7 +406,8 @@ static int page_referenced_file(struct page *page) 
 * Quick test_and_clear_referenced for all mappings to a page,

 * returns the number of ptes which referenced the page.

 */

int page_referenced(struct page *page, int is_locked)

int page_referenced(struct page *page, int is_locked,

			struct mem_cgroup *mem_cont)

{

	int referenced = 0;
@@ -402,14 +419,15 @@ int page_referenced(struct page *page, int is_locked) 


	if (page_mapped(page) && page->mapping) {

		if (PageAnon(page))

			referenced += page_referenced_anon(page);

			referenced += page_referenced_anon(page, mem_cont);

		else if (is_locked)

			referenced += page_referenced_file(page);

			referenced += page_referenced_file(page, mem_cont);

		else if (TestSetPageLocked(page))

			referenced++;

		else {

			if (page->mapping)

				referenced += page_referenced_file(page);

				referenced +=

					page_referenced_file(page, mem_cont);

			unlock_page(page);

		}

	}

mm/vmscan.c

+2 −2
Original line number Diff line number Diff line
@@ -503,7 +503,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, 
				goto keep_locked;

		}



		referenced = page_referenced(page, 1);

		referenced = page_referenced(page, 1, sc->mem_cgroup);

		/* In active use or really unfreeable?  Activate it. */

		if (sc->order <= PAGE_ALLOC_COSTLY_ORDER &&

					referenced && page_mapping_inuse(page))
@@ -1057,7 +1057,7 @@ force_reclaim_mapped: 
		if (page_mapped(page)) {

			if (!reclaim_mapped ||

			    (total_swap_pages == 0 && PageAnon(page)) ||

			    page_referenced(page, 0)) {

			    page_referenced(page, 0, sc->mem_cgroup)) {

				list_add(&page->lru, &l_active);

				continue;

			}