Commit b7abea96 authored by KAMEZAWA Hiroyuki's avatar KAMEZAWA Hiroyuki Committed by Linus Torvalds
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memcg: make page->mapping NULL before uncharge 



This patch tries to make page->mapping to be NULL before
mem_cgroup_uncharge_cache_page() is called.

"page->mapping == NULL" is a good check for "whether the page is still
radix-tree or not".  This patch also adds BUG_ON() to
mem_cgroup_uncharge_cache_page();

Signed-off-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: default avatarDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@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 073e587e

mm/filemap.c

+1 −1
Original line number Diff line number Diff line
@@ -116,12 +116,12 @@ void __remove_from_page_cache(struct page *page) 
{

	struct address_space *mapping = page->mapping;



	mem_cgroup_uncharge_cache_page(page);

	radix_tree_delete(&mapping->page_tree, page->index);

	page->mapping = NULL;

	mapping->nrpages--;

	__dec_zone_page_state(page, NR_FILE_PAGES);

	BUG_ON(page_mapped(page));

	mem_cgroup_uncharge_cache_page(page);



	/*

	 * Some filesystems seem to re-dirty the page even after

mm/memcontrol.c

+1 −0
Original line number Diff line number Diff line
@@ -734,6 +734,7 @@ void mem_cgroup_uncharge_page(struct page *page) 
void mem_cgroup_uncharge_cache_page(struct page *page)

{

	VM_BUG_ON(page_mapped(page));

	VM_BUG_ON(page->mapping);

	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);

}

mm/migrate.c

+7 −2
Original line number Diff line number Diff line
@@ -330,8 +330,6 @@ static int migrate_page_move_mapping(struct address_space *mapping, 
	__inc_zone_page_state(newpage, NR_FILE_PAGES);



	spin_unlock_irq(&mapping->tree_lock);

	if (!PageSwapCache(newpage))

		mem_cgroup_uncharge_cache_page(page);



	return 0;

}
@@ -341,6 +339,8 @@ static int migrate_page_move_mapping(struct address_space *mapping, 
 */

static void migrate_page_copy(struct page *newpage, struct page *page)

{

	int anon;



	copy_highpage(newpage, page);



	if (PageError(page))
@@ -378,8 +378,13 @@ static void migrate_page_copy(struct page *newpage, struct page *page) 
#endif

	ClearPagePrivate(page);

	set_page_private(page, 0);

	/* page->mapping contains a flag for PageAnon() */

	anon = PageAnon(page);

	page->mapping = NULL;



	if (!anon) /* This page was removed from radix-tree. */

		mem_cgroup_uncharge_cache_page(page);



	/*

	 * If any waiters have accumulated on the new page then

	 * wake them up.

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