memcg: move page-freeing code out of lock
Move page-freeing code out of swap_cgroup_mutex in the hope that it could
reduce few of theoretical contentions between swapons and/or swapoffs.
This is just a cleanup, no functional changes.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index 5524e8b..74ccff6 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -492,8 +492,8 @@
/* memory shortage */
ctrl->map = NULL;
ctrl->length = 0;
- vfree(array);
mutex_unlock(&swap_cgroup_mutex);
+ vfree(array);
goto nomem;
}
mutex_unlock(&swap_cgroup_mutex);
@@ -508,7 +508,8 @@
void swap_cgroup_swapoff(int type)
{
- int i;
+ struct page **map;
+ unsigned long i, length;
struct swap_cgroup_ctrl *ctrl;
if (!do_swap_account)
@@ -516,17 +517,20 @@
mutex_lock(&swap_cgroup_mutex);
ctrl = &swap_cgroup_ctrl[type];
- if (ctrl->map) {
- for (i = 0; i < ctrl->length; i++) {
- struct page *page = ctrl->map[i];
+ map = ctrl->map;
+ length = ctrl->length;
+ ctrl->map = NULL;
+ ctrl->length = 0;
+ mutex_unlock(&swap_cgroup_mutex);
+
+ if (map) {
+ for (i = 0; i < length; i++) {
+ struct page *page = map[i];
if (page)
__free_page(page);
}
- vfree(ctrl->map);
- ctrl->map = NULL;
- ctrl->length = 0;
+ vfree(map);
}
- mutex_unlock(&swap_cgroup_mutex);
}
#endif