From b7abea9630bc8ffc663a751e46680db25c4cdf8d Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Sat, 18 Oct 2008 20:28:09 -0700 Subject: 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: KAMEZAWA Hiroyuki Reviewed-by: Daisuke Nishimura Cc: Balbir Singh Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/migrate.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 11c6c56ec017..6602941bfab0 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -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. -- cgit v1.2.2