mm: memcg: only check for PageSwapCache when uncharging anon
authorJohannes Weiner <hannes@cmpxchg.org>
Tue, 31 Jul 2012 23:45:34 +0000 (16:45 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 1 Aug 2012 01:42:48 +0000 (18:42 -0700)
Only anon pages that are uncharged at the time of the last page table
mapping vanishing may be in swapcache.

When shmem pages, file pages, swap-freed anon pages, or just migrated
pages are uncharged, they are known for sure to be not in swapcache.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Wanpeng Li <liwp.linux@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/memcontrol.c

index 87c2ec49b4825303b1ba48b98b844c88fb3bab76..29bc4400378d6766bcb04b375eaeba847b236035 100644 (file)
@@ -3093,8 +3093,6 @@ void mem_cgroup_uncharge_cache_page(struct page *page)
 {
        VM_BUG_ON(page_mapped(page));
        VM_BUG_ON(page->mapping);
-       if (PageSwapCache(page))
-               return;
        __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false);
 }
 
@@ -3159,8 +3157,6 @@ mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
        if (!swapout) /* this was a swap cache but the swap is unused ! */
                ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
 
-       if (PageSwapCache(page))
-               return;
        memcg = __mem_cgroup_uncharge_common(page, ctype, false);
 
        /*
@@ -3350,11 +3346,10 @@ void mem_cgroup_end_migration(struct mem_cgroup *memcg,
                unused = oldpage;
        }
        anon = PageAnon(used);
-       if (!PageSwapCache(unused))
-               __mem_cgroup_uncharge_common(unused,
-                                            anon ? MEM_CGROUP_CHARGE_TYPE_ANON
-                                            : MEM_CGROUP_CHARGE_TYPE_CACHE,
-                                            true);
+       __mem_cgroup_uncharge_common(unused,
+                                    anon ? MEM_CGROUP_CHARGE_TYPE_ANON
+                                    : MEM_CGROUP_CHARGE_TYPE_CACHE,
+                                    true);
        css_put(&memcg->css);
        /*
         * We disallowed uncharge of pages under migration because mapcount