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Commit ad8c2ee8 authored by Rik van Riel's avatar Rik van Riel Committed by Linus Torvalds
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rmap: add exclusive page to private anon_vma on swapin 



On swapin it is fairly common for a page to be owned exclusively by one
process.  In that case we want to add the page to the anon_vma of that
process's VMA, instead of to the root anon_vma.

This will reduce the amount of rmap searching that the swapout code needs
to do.

Signed-off-by: default avatarRik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 51b1bd2a

include/linux/rmap.h

+2 −0
Original line number Diff line number Diff line
@@ -162,6 +162,8 @@ static inline void anon_vma_merge(struct vm_area_struct *vma, 
 */

void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);

void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);

void do_page_add_anon_rmap(struct page *, struct vm_area_struct *,

			   unsigned long, int);

void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);

void page_add_file_rmap(struct page *);

void page_remove_rmap(struct page *);

mm/memory.c

+3 −1
Original line number Diff line number Diff line
@@ -2628,6 +2628,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, 
	swp_entry_t entry;

	pte_t pte;

	struct mem_cgroup *ptr = NULL;

	int exclusive = 0;

	int ret = 0;



	if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
@@ -2722,10 +2723,11 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, 
	if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {

		pte = maybe_mkwrite(pte_mkdirty(pte), vma);

		flags &= ~FAULT_FLAG_WRITE;

		exclusive = 1;

	}

	flush_icache_page(vma, page);

	set_pte_at(mm, address, page_table, pte);

	page_add_anon_rmap(page, vma, address);

	do_page_add_anon_rmap(page, vma, address, exclusive);

	/* It's better to call commit-charge after rmap is established */

	mem_cgroup_commit_charge_swapin(page, ptr);

mm/rmap.c

+12 −1
Original line number Diff line number Diff line
@@ -829,6 +829,17 @@ static void __page_check_anon_rmap(struct page *page, 
 */

void page_add_anon_rmap(struct page *page,

	struct vm_area_struct *vma, unsigned long address)

{

	do_page_add_anon_rmap(page, vma, address, 0);

}



/*

 * Special version of the above for do_swap_page, which often runs

 * into pages that are exclusively owned by the current process.

 * Everybody else should continue to use page_add_anon_rmap above.

 */

void do_page_add_anon_rmap(struct page *page,

	struct vm_area_struct *vma, unsigned long address, int exclusive)

{

	int first = atomic_inc_and_test(&page->_mapcount);

	if (first)
@@ -839,7 +850,7 @@ void page_add_anon_rmap(struct page *page, 
	VM_BUG_ON(!PageLocked(page));

	VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end);

	if (first)

		__page_set_anon_rmap(page, vma, address, 0);

		__page_set_anon_rmap(page, vma, address, exclusive);

	else

		__page_check_anon_rmap(page, vma, address);

}