@@ -287,7 +287,11 @@ struct mem_cgroup {
 	 * Should the accounting and control be hierarchical, per subtree?
 	 */
 	bool use_hierarchy;
-	bool kmem_accounted;
+	/*
+	 * bit0: accounted by this cgroup
+	 * bit1: accounted by a parent.
+	 */
+	volatile unsigned long kmem_accounted;
 
 	bool		oom_lock;
 	atomic_t	under_oom;

@@ -340,6 +344,9 @@ struct mem_cgroup {
 #endif
 };
 
+#define KMEM_ACCOUNTED_THIS	0
+#define KMEM_ACCOUNTED_PARENT	1
+
 /* Stuffs for move charges at task migration. */
 /*
  * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a

@@ -589,7 +596,7 @@ EXPORT_SYMBOL(__mem_cgroup_free_kmem_page);
 
 static void disarm_kmem_keys(struct mem_cgroup *memcg)
 {
-	if (memcg->kmem_accounted)
+	if (test_bit(KMEM_ACCOUNTED_THIS, &memcg->kmem_accounted))
 		static_key_slow_dec(&mem_cgroup_kmem_enabled_key);
 }
 #else

@@ -4027,6 +4034,66 @@ static ssize_t mem_cgroup_read(struct cgroup *cont, struct cftype *cft,
 	len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);
 	return simple_read_from_buffer(buf, nbytes, ppos, str, len);
 }
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+static void mem_cgroup_update_kmem_limit(struct mem_cgroup *memcg, u64 val)
+{
+	struct mem_cgroup *iter;
+
+	mutex_lock(&set_limit_mutex);
+	if (!test_and_set_bit(KMEM_ACCOUNTED_THIS, &memcg->kmem_accounted) &&
+		val != RESOURCE_MAX) {
+
+		/*
+		 * Once enabled, can't be disabled. We could in theory
+		 * disable it if we haven't yet created any caches, or
+		 * if we can shrink them all to death.
+		 *
+		 * But it is not worth the trouble
+		 */
+		static_key_slow_inc(&mem_cgroup_kmem_enabled_key);
+
+		if (!memcg->use_hierarchy)
+			goto out;
+
+		for_each_mem_cgroup_tree(iter, memcg) {
+			if (iter == memcg)
+				continue;
+			set_bit(KMEM_ACCOUNTED_PARENT, &iter->kmem_accounted);
+		}
+
+	} else if (test_and_clear_bit(KMEM_ACCOUNTED_THIS, &memcg->kmem_accounted)
+		&& val == RESOURCE_MAX) {
+
+		if (!memcg->use_hierarchy)
+			goto out;
+
+		for_each_mem_cgroup_tree(iter, memcg) {
+			struct mem_cgroup *parent;
+			if (iter == memcg)
+				continue;
+			/*
+			 * We should only have our parent bit cleared if none of
+			 * ouri parents are accounted. The transversal order of
+			 * our iter function forces us to always look at the
+			 * parents.
+			 */
+			parent = parent_mem_cgroup(iter);
+			while (parent && (parent != memcg)) {
+				if (test_bit(KMEM_ACCOUNTED_THIS, &parent->kmem_accounted))
+					goto noclear;
+					
+				parent = parent_mem_cgroup(parent);
+			}
+			clear_bit(KMEM_ACCOUNTED_PARENT, &iter->kmem_accounted);
+noclear:
+			continue;
+		}
+	}
+out:
+	mutex_unlock(&set_limit_mutex);
+}
+#endif
 /*
  * The user of this function is...
  * RES_LIMIT.

@@ -4064,19 +4131,8 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
 			ret = res_counter_set_limit(&memcg->kmem, val);
 			if (ret)
 				break;
-			/*
-			 * Once enabled, can't be disabled. We could in theory
-			 * disable it if we haven't yet created any caches, or
-			 * if we can shrink them all to death.
-			 *
-			 * But it is not worth the trouble
-			 */
-			mutex_lock(&set_limit_mutex);
-			if (!memcg->kmem_accounted && val != RESOURCE_MAX) {
-				static_key_slow_inc(&mem_cgroup_kmem_enabled_key);
-				memcg->kmem_accounted = true;
-			}
-			mutex_unlock(&set_limit_mutex);
+			mem_cgroup_update_kmem_limit(memcg, val);
+			break;
 		}
 #endif
 		else