Swapping tmpfs loads show absurd wrapped rss and wrong cache in memcg's
memory.stat statistics: __mem_cgroup_uncharge_common() is failing to
distinguish the anon and tmpfs cases.
Mostly we can decide between them by PageAnon, which is reliable once
it has been set; but there are several callers who need to uncharge a
MEM_CGROUP_CHARGE_TYPE_MAPPED page before it was fully initialized,
so allow that case to override the PageAnon decision.
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
---
mm/memcontrol.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- 3.3-rc5-next/mm/memcontrol.c 2012-02-25 10:06:52.496035568 -0800
+++ linux/mm/memcontrol.c 2012-02-26 10:44:32.146365398 -0800
@@ -2944,13 +2944,16 @@ __mem_cgroup_uncharge_common(struct page
if (!PageCgroupUsed(pc))
goto unlock_out;
+ anon = PageAnon(page);
+
switch (ctype) {
case MEM_CGROUP_CHARGE_TYPE_MAPPED:
+ anon = true;
+ /* fallthrough */
case MEM_CGROUP_CHARGE_TYPE_DROP:
/* See mem_cgroup_prepare_migration() */
if (page_mapped(page) || PageCgroupMigration(pc))
goto unlock_out;
- anon = true;
break;
case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
if (!PageAnon(page)) { /* Shared memory */
@@ -2958,10 +2961,8 @@ __mem_cgroup_uncharge_common(struct page
goto unlock_out;
} else if (page_mapped(page)) /* Anon */
goto unlock_out;
- anon = true;
break;
default:
- anon = false;
break;
}
--
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