Commit 6fe6b7e3 authored by Wu Fengguang's avatar Wu Fengguang Committed by Linus Torvalds
Browse files

vmscan: report vm_flags in page_referenced() 



Collect vma->vm_flags of the VMAs that actually referenced the page.

This is preparing for more informed reclaim heuristics, eg.  to protect
executable file pages more aggressively.  For now only the VM_EXEC bit
will be used by the caller.

Thanks to Johannes, Peter and Minchan for all the good tips.

Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Reviewed-by: default avatarRik van Riel <riel@redhat.com>
Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
Reviewed-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 608e8e66

include/linux/rmap.h

+3 −2
Original line number Diff line number Diff line
@@ -83,7 +83,8 @@ 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, struct mem_cgroup *cnt);

int page_referenced(struct page *, int is_locked,

			struct mem_cgroup *cnt, unsigned long *vm_flags);

int try_to_unmap(struct page *, int ignore_refs);



/*
@@ -117,7 +118,7 @@ int try_to_munlock(struct page *); 
#define anon_vma_prepare(vma)	(0)

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



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

#define page_referenced(page, locked, cnt, flags) TestClearPageReferenced(page)

#define try_to_unmap(page, refs) SWAP_FAIL



static inline int page_mkclean(struct page *page)

mm/rmap.c

+26 −11
Original line number Diff line number Diff line
@@ -333,7 +333,9 @@ static int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma) 
 * repeatedly from either page_referenced_anon or page_referenced_file.

 */

static int page_referenced_one(struct page *page,

	struct vm_area_struct *vma, unsigned int *mapcount)

			       struct vm_area_struct *vma,

			       unsigned int *mapcount,

			       unsigned long *vm_flags)

{

	struct mm_struct *mm = vma->vm_mm;

	unsigned long address;
@@ -381,11 +383,14 @@ out_unmap: 
	(*mapcount)--;

	pte_unmap_unlock(pte, ptl);

out:

	if (referenced)

		*vm_flags |= vma->vm_flags;

	return referenced;

}



static int page_referenced_anon(struct page *page,

				struct mem_cgroup *mem_cont)

				struct mem_cgroup *mem_cont,

				unsigned long *vm_flags)

{

	unsigned int mapcount;

	struct anon_vma *anon_vma;
@@ -405,7 +410,8 @@ static int page_referenced_anon(struct page *page, 
		 */

		if (mem_cont && !mm_match_cgroup(vma->vm_mm, mem_cont))

			continue;

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

		referenced += page_referenced_one(page, vma,

						  &mapcount, vm_flags);

		if (!mapcount)

			break;

	}
@@ -418,6 +424,7 @@ static int page_referenced_anon(struct page *page, 
 * page_referenced_file - referenced check for object-based rmap

 * @page: the page we're checking references on.

 * @mem_cont: target memory controller

 * @vm_flags: collect encountered vma->vm_flags who actually referenced the page

 *

 * For an object-based mapped page, find all the places it is mapped and

 * check/clear the referenced flag.  This is done by following the page->mapping
@@ -427,7 +434,8 @@ 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,

				struct mem_cgroup *mem_cont)

				struct mem_cgroup *mem_cont,

				unsigned long *vm_flags)

{

	unsigned int mapcount;

	struct address_space *mapping = page->mapping;
@@ -467,7 +475,8 @@ static int page_referenced_file(struct page *page, 
		 */

		if (mem_cont && !mm_match_cgroup(vma->vm_mm, mem_cont))

			continue;

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

		referenced += page_referenced_one(page, vma,

						  &mapcount, vm_flags);

		if (!mapcount)

			break;

	}
@@ -481,29 +490,35 @@ static int page_referenced_file(struct page *page, 
 * @page: the page to test

 * @is_locked: caller holds lock on the page

 * @mem_cont: target memory controller

 * @vm_flags: collect encountered vma->vm_flags who actually referenced the 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,

			struct mem_cgroup *mem_cont)

int page_referenced(struct page *page,

		    int is_locked,

		    struct mem_cgroup *mem_cont,

		    unsigned long *vm_flags)

{

	int referenced = 0;



	if (TestClearPageReferenced(page))

		referenced++;



	*vm_flags = 0;

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

		if (PageAnon(page))

			referenced += page_referenced_anon(page, mem_cont);

			referenced += page_referenced_anon(page, mem_cont,

								vm_flags);

		else if (is_locked)

			referenced += page_referenced_file(page, mem_cont);

			referenced += page_referenced_file(page, mem_cont,

								vm_flags);

		else if (!trylock_page(page))

			referenced++;

		else {

			if (page->mapping)

				referenced +=

					page_referenced_file(page, mem_cont);

				referenced += page_referenced_file(page,

							mem_cont, vm_flags);

			unlock_page(page);

		}

	}

mm/vmscan.c

+5 −2
Original line number Diff line number Diff line
@@ -577,6 +577,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, 
	struct pagevec freed_pvec;

	int pgactivate = 0;

	unsigned long nr_reclaimed = 0;

	unsigned long vm_flags;



	cond_resched();
@@ -627,7 +628,8 @@ static unsigned long shrink_page_list(struct list_head *page_list, 
				goto keep_locked;

		}



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

		referenced = page_referenced(page, 1,

						sc->mem_cgroup, &vm_flags);

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

		if (sc->order <= PAGE_ALLOC_COSTLY_ORDER &&

					referenced && page_mapping_inuse(page))
@@ -1208,6 +1210,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, 
{

	unsigned long pgmoved;

	unsigned long pgscanned;

	unsigned long vm_flags;

	LIST_HEAD(l_hold);	/* The pages which were snipped off */

	LIST_HEAD(l_inactive);

	struct page *page;
@@ -1248,7 +1251,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, 


		/* page_referenced clears PageReferenced */

		if (page_mapping_inuse(page) &&

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

		    page_referenced(page, 0, sc->mem_cgroup, &vm_flags))

			pgmoved++;



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

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