From b24028572fb69e9dd6de8c359eba2b2c66baa889 Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Wed, 21 Mar 2012 16:34:22 -0700 Subject: memcg: remove PCG_CACHE page_cgroup flag We record 'the page is cache' with the PCG_CACHE bit in page_cgroup. Here, "CACHE" means anonymous user pages (and SwapCache). This doesn't include shmem. Considering callers, at charge/uncharge, the caller should know what the page is and we don't need to record it by using one bit per page. This patch removes PCG_CACHE bit and make callers of mem_cgroup_charge_statistics() to specify what the page is. About page migration: Mapping of the used page is not touched during migra tion (see page_remove_rmap) so we can rely on it and push the correct charge type down to __mem_cgroup_uncharge_common from end_migration for unused page. The force flag was misleading was abused for skipping the needless page_mapped() / PageCgroupMigration() check, as we know the unused page is no longer mapped and cleared the migration flag just a few lines up. But doing the checks is no biggie and it's not worth adding another flag just to skip them. [akpm@linux-foundation.org: checkpatch fixes] [hughd@google.com: fix PageAnon uncharging] Signed-off-by: KAMEZAWA Hiroyuki Acked-by: Michal Hocko Acked-by: Johannes Weiner Cc: Hugh Dickins Cc: Ying Han Acked-by: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/page_cgroup.h | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) (limited to 'include/linux/page_cgroup.h') diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h index a2d11771c84b..106029243ff4 100644 --- a/include/linux/page_cgroup.h +++ b/include/linux/page_cgroup.h @@ -4,7 +4,6 @@ enum { /* flags for mem_cgroup */ PCG_LOCK, /* Lock for pc->mem_cgroup and following bits. */ - PCG_CACHE, /* charged as cache */ PCG_USED, /* this object is in use. */ PCG_MIGRATION, /* under page migration */ /* flags for mem_cgroup and file and I/O status */ @@ -64,11 +63,6 @@ static inline void ClearPageCgroup##uname(struct page_cgroup *pc) \ static inline int TestClearPageCgroup##uname(struct page_cgroup *pc) \ { return test_and_clear_bit(PCG_##lname, &pc->flags); } -/* Cache flag is set only once (at allocation) */ -TESTPCGFLAG(Cache, CACHE) -CLEARPCGFLAG(Cache, CACHE) -SETPCGFLAG(Cache, CACHE) - TESTPCGFLAG(Used, USED) CLEARPCGFLAG(Used, USED) SETPCGFLAG(Used, USED) @@ -85,7 +79,7 @@ static inline void lock_page_cgroup(struct page_cgroup *pc) { /* * Don't take this lock in IRQ context. - * This lock is for pc->mem_cgroup, USED, CACHE, MIGRATION + * This lock is for pc->mem_cgroup, USED, MIGRATION */ bit_spin_lock(PCG_LOCK, &pc->flags); } -- cgit v1.2.3