diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 2cccbb9e1b3ec9790cbaed3f9c82de7f7f2bd0a4..258c8a46959a9d27e07f851ad0acfc194c619c4e 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -318,6 +318,11 @@ struct mem_cgroup {
 
 extern struct mem_cgroup *root_mem_cgroup;
 
+static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
+{
+	return (memcg == root_mem_cgroup);
+}
+
 static inline bool mem_cgroup_disabled(void)
 {
 	return !cgroup_subsys_enabled(memory_cgrp_subsys);
@@ -784,6 +789,11 @@ void mem_cgroup_split_huge_fixup(struct page *head);
 
 struct mem_cgroup;
 
+static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
+{
+	return true;
+}
+
 static inline bool mem_cgroup_disabled(void)
 {
 	return true;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a35dc901424d1789ff4a73e8ac5bcc9040a26c52..d8cd6c39eca59af3db71c6aee122dcbe16972b03 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -261,11 +261,6 @@ struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
 	return &container_of(vmpr, struct mem_cgroup, vmpressure)->css;
 }
 
-static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
-{
-	return (memcg == root_mem_cgroup);
-}
-
 #ifdef CONFIG_MEMCG_KMEM
 /*
  * This will be the memcg's index in each cache's ->memcg_params.memcg_caches.