tweak comments

Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/memcontrol.c

@@ -1296,8 +1296,7 @@ static bool consume_stock(struct mem_cgroup *mem)
 }
 
 /*
- * Retruens stocks cached in percpu to res_counter and reset
- * cached information.
+ * Returns stocks cached in percpu to res_counter and reset cached information.
  */
 static void drain_stock(struct memcg_stock_pcp *stock)
 {
@@ -1326,7 +1325,6 @@ static void drain_local_stock(struct work_struct *dummy)
  * Cache charges(val) which is from res_counter, to local per_cpu area.
  * This will be consumed by consumt_stock() function, later.
  */
-
 static void refill_stock(struct mem_cgroup *mem, int val)
 {
 	struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
@@ -1345,7 +1343,6 @@ static void refill_stock(struct mem_cgroup *mem, int val)
  * expects some charges will be back to res_counter later but cannot wait for
  * it.
  */
-
 static void drain_all_stock_async(void)
 {
 	int cpu;