From e8589cc189f96b87348ae83ea4db38eaac624135 Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Fri, 25 Jul 2008 01:47:10 -0700 Subject: memcg: better migration handling This patch changes page migration under memory controller to use a different algorithm. (thanks to Christoph for new idea.) Before: - page_cgroup is migrated from an old page to a new page. After: - a new page is accounted , no reuse of page_cgroup. Pros: - We can avoid compliated lock depndencies and races in migration. Cons: - new param to mem_cgroup_charge_common(). - mem_cgroup_getref() is added for handling ref_cnt ping-pong. This version simplifies complicated lock dependency in page migraiton under memory resource controller. new refcnt sequence is following. a mapped page: prepage_migration() ..... +1 to NEW page try_to_unmap() ..... all refs to OLD page is gone. move_pages() ..... +1 to NEW page if page cache. remap... ..... all refs from *map* is added to NEW one. end_migration() ..... -1 to New page. page's mapcount + (page_is_cache) refs are added to NEW one. Signed-off-by: KAMEZAWA Hiroyuki Cc: Balbir Singh Cc: Pavel Emelyanov Cc: Li Zefan Cc: YAMAMOTO Takashi Cc: Hugh Dickins Cc: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'include') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index e6608776bc9..84ead2aa6f1 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -50,9 +50,10 @@ extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p); #define mm_match_cgroup(mm, cgroup) \ ((cgroup) == mem_cgroup_from_task((mm)->owner)) -extern int mem_cgroup_prepare_migration(struct page *page); +extern int +mem_cgroup_prepare_migration(struct page *page, struct page *newpage); extern void mem_cgroup_end_migration(struct page *page); -extern void mem_cgroup_page_migration(struct page *page, struct page *newpage); +extern int mem_cgroup_getref(struct page *page); /* * For memory reclaim. @@ -112,7 +113,8 @@ static inline int task_in_mem_cgroup(struct task_struct *task, return 1; } -static inline int mem_cgroup_prepare_migration(struct page *page) +static inline int +mem_cgroup_prepare_migration(struct page *page, struct page *newpage) { return 0; } @@ -121,8 +123,7 @@ static inline void mem_cgroup_end_migration(struct page *page) { } -static inline void -mem_cgroup_page_migration(struct page *page, struct page *newpage) +static inline void mem_cgroup_getref(struct page *page) { } -- cgit v1.2.3