memcg: add accessor to mem_cgroup.css
So that an outside user can free the reference count grabbed by
try_get_mem_cgroup_from_page().
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Hugh Dickins <hugh.dickins@tiscali.co.uk>
CC: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
CC: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index fc9bae8..2c30a11 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -81,6 +81,8 @@
return cgroup == mem;
}
+extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem);
+
extern int
mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr);
extern void mem_cgroup_end_migration(struct mem_cgroup *mem,
@@ -206,6 +208,11 @@
return 1;
}
+static inline struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
+{
+ return NULL;
+}
+
static inline int
mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
{
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b5ac61c..9eee80d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -282,6 +282,11 @@
return &mem->info.nodeinfo[nid]->zoneinfo[zid];
}
+struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
+{
+ return &mem->css;
+}
+
static struct mem_cgroup_per_zone *
page_cgroup_zoneinfo(struct page_cgroup *pc)
{