The patch titled
memcg: fix try_get_mem_cgroup_from_swapcache()
has been added to the -mm tree. Its filename is
memcg-fix-try_get_mem_cgroup_from_swapcache.patch
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------------------------------------------------------
Subject: memcg: fix try_get_mem_cgroup_from_swapcache()
From: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
This is a bugfix for commit 3c776e64660028236313f0e54f3a9945764422df
("memcg: charge swapcache to proper memcg").
Used bit of swapcache is solid under page lock, but considering
move_account, pc->mem_cgroup is not.
We need lock_page_cgroup() anyway.
Signed-off-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff -puN mm/memcontrol.c~memcg-fix-try_get_mem_cgroup_from_swapcache mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-fix-try_get_mem_cgroup_from_swapcache
+++ a/mm/memcontrol.c
@@ -1024,9 +1024,7 @@ static struct mem_cgroup *try_get_mem_cg
return NULL;
pc = lookup_page_cgroup(page);
- /*
- * Used bit of swapcache is solid under page lock.
- */
+ lock_page_cgroup(pc);
if (PageCgroupUsed(pc)) {
mem = pc->mem_cgroup;
if (mem && !css_tryget(&mem->css))
@@ -1040,6 +1038,7 @@ static struct mem_cgroup *try_get_mem_cg
mem = NULL;
rcu_read_unlock();
}
+ unlock_page_cgroup(pc);
return mem;
}
_
Patches currently in -mm which might be from nishimura@xxxxxxxxxxxxxxxxx are
memcg-fix-try_get_mem_cgroup_from_swapcache.patch
memcg-fix-mem_cgroup_shrink_usage.patch
memcg-add-file-based-rss-accounting.patch
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