memcg: rename and export try_get_mem_cgroup_from_page()
So that the hwpoison injector can get mem_cgroup for arbitrary page
and thus know whether it is owned by some mem_cgroup task(s).
[AK: Merged with latest git tree]
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 bf9213b..fc9bae8 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -68,6 +68,7 @@
extern void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask);
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem);
+extern struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page);
extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
static inline
@@ -189,6 +190,11 @@
{
}
+static inline struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
+{
+ return NULL;
+}
+
static inline int mm_match_cgroup(struct mm_struct *mm, struct mem_cgroup *mem)
{
return 1;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e0c2066..b5ac61c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1379,25 +1379,22 @@
return container_of(css, struct mem_cgroup, css);
}
-static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
+struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
{
- struct mem_cgroup *mem;
+ struct mem_cgroup *mem = NULL;
struct page_cgroup *pc;
unsigned short id;
swp_entry_t ent;
VM_BUG_ON(!PageLocked(page));
- if (!PageSwapCache(page))
- return NULL;
-
pc = lookup_page_cgroup(page);
lock_page_cgroup(pc);
if (PageCgroupUsed(pc)) {
mem = pc->mem_cgroup;
if (mem && !css_tryget(&mem->css))
mem = NULL;
- } else {
+ } else if (PageSwapCache(page)) {
ent.val = page_private(page);
id = lookup_swap_cgroup(ent);
rcu_read_lock();
@@ -1743,7 +1740,7 @@
*/
if (!PageSwapCache(page))
goto charge_cur_mm;
- mem = try_get_mem_cgroup_from_swapcache(page);
+ mem = try_get_mem_cgroup_from_page(page);
if (!mem)
goto charge_cur_mm;
*ptr = mem;
