From d435edca928805074dae005ab9a42d9fa60fc702 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Tue, 15 Mar 2016 14:56:15 -0700 Subject: mm, page_owner: copy page owner info during migration The page_owner mechanism stores gfp_flags of an allocation and stack trace that lead to it. During page migration, the original information is practically replaced by the allocation of free page as the migration target. Arguably this is less useful and might lead to all the page_owner info for migratable pages gradually converge towards compaction or numa balancing migrations. It has also lead to inaccuracies such as one fixed by commit e2cfc91120fa ("mm/page_owner: set correct gfp_mask on page_owner"). This patch thus introduces copying the page_owner info during migration. However, since the fact that the page has been migrated from its original place might be useful for debugging, the next patch will introduce a way to track that information as well. Signed-off-by: Vlastimil Babka Acked-by: Michal Hocko Cc: Joonsoo Kim Cc: Minchan Kim Cc: Sasha Levin Cc: "Kirill A. Shutemov" Cc: Mel Gorman Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/page_owner.h | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'include/linux/page_owner.h') diff --git a/include/linux/page_owner.h b/include/linux/page_owner.h index 8e2eb153c7b9..6440daab4ef8 100644 --- a/include/linux/page_owner.h +++ b/include/linux/page_owner.h @@ -11,6 +11,7 @@ extern void __reset_page_owner(struct page *page, unsigned int order); extern void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask); extern gfp_t __get_page_owner_gfp(struct page *page); +extern void __copy_page_owner(struct page *oldpage, struct page *newpage); static inline void reset_page_owner(struct page *page, unsigned int order) { @@ -32,6 +33,11 @@ static inline gfp_t get_page_owner_gfp(struct page *page) else return 0; } +static inline void copy_page_owner(struct page *oldpage, struct page *newpage) +{ + if (static_branch_unlikely(&page_owner_inited)) + __copy_page_owner(oldpage, newpage); +} #else static inline void reset_page_owner(struct page *page, unsigned int order) { @@ -44,6 +50,8 @@ static inline gfp_t get_page_owner_gfp(struct page *page) { return 0; } - +static inline void copy_page_owner(struct page *oldpage, struct page *newpage) +{ +} #endif /* CONFIG_PAGE_OWNER */ #endif /* __LINUX_PAGE_OWNER_H */ -- cgit v1.2.3