Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>

Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/memcontrol.c

@@ -496,7 +496,7 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
 					 struct page_cgroup *pc,
 					 bool charge)
 {
-	int val = (charge)? 1 : -1;
+	int val = (charge) ? 1 : -1;
 	struct mem_cgroup_stat *stat = &mem->stat;
 	struct mem_cgroup_stat_cpu *cpustat;
 	int cpu = get_cpu();
@@ -1893,7 +1893,7 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
 				(ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
 			res_counter_uncharge(&mem->memsw, PAGE_SIZE, NULL);
 	}
-	if (ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT && mem_cgroup_is_root(mem))
+	if (ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
 		mem_cgroup_swap_statistics(mem, true);
 	mem_cgroup_charge_statistics(mem, pc, false);
 
@@ -2499,10 +2499,34 @@ static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
 	return retval;
 }
 
+struct mem_cgroup_idx_data {
+	s64 val;
+	enum mem_cgroup_stat_index idx;
+};
+
+static int
+mem_cgroup_get_idx_stat(struct mem_cgroup *mem, void *data)
+{
+	struct mem_cgroup_idx_data *d = data;
+	d->val += mem_cgroup_read_stat(&mem->stat, d->idx);
+	return 0;
+}
+
+static void
+mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem,
+				enum mem_cgroup_stat_index idx, s64 *val)
+{
+	struct mem_cgroup_idx_data d;
+	d.idx = idx;
+	d.val = 0;
+	mem_cgroup_walk_tree(mem, &d, mem_cgroup_get_idx_stat);
+	*val = d.val;
+}
+
 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
 {
 	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
-	u64 val = 0;
+	u64 idx_val, val;
 	int type, name;
 
 	type = MEMFILE_TYPE(cft->private);
@@ -2510,22 +2534,26 @@ static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
 	switch (type) {
 	case _MEM:
 		if (name == RES_USAGE && mem_cgroup_is_root(mem)) {
-			val = mem_cgroup_read_stat(&mem->stat,
-					MEM_CGROUP_STAT_CACHE);
-			val += mem_cgroup_read_stat(&mem->stat,
-					MEM_CGROUP_STAT_RSS);
+			mem_cgroup_get_recursive_idx_stat(mem,
+				MEM_CGROUP_STAT_CACHE, &idx_val);
+			val = idx_val;
+			mem_cgroup_get_recursive_idx_stat(mem,
+				MEM_CGROUP_STAT_RSS, &idx_val);
+			val += idx_val;
 			val <<= PAGE_SHIFT;
 		} else
 			val = res_counter_read_u64(&mem->res, name);
 		break;
 	case _MEMSWAP:
 		if (name == RES_USAGE && mem_cgroup_is_root(mem)) {
-			val = mem_cgroup_read_stat(&mem->stat,
-					MEM_CGROUP_STAT_CACHE);
-			val += mem_cgroup_read_stat(&mem->stat,
-					MEM_CGROUP_STAT_RSS);
-			val += mem_cgroup_read_stat(&mem->stat,
-					MEM_CGROUP_STAT_SWAPOUT);
+			mem_cgroup_get_recursive_idx_stat(mem,
+				MEM_CGROUP_STAT_CACHE, &idx_val);
+			val = idx_val;
+			mem_cgroup_get_recursive_idx_stat(mem,
+				MEM_CGROUP_STAT_RSS, &idx_val);
+			val += idx_val;
+			mem_cgroup_get_recursive_idx_stat(mem,
+				MEM_CGROUP_STAT_SWAPOUT, &idx_val);
 			val <<= PAGE_SHIFT;
 		} else
 			val = res_counter_read_u64(&mem->memsw, name);