diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index ac1b003ee5b8..9ed75f82b858 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1057,6 +1057,7 @@ static inline u64 cgroup_id_from_mm(struct mm_struct *mm)
 	return id;
 }
 
+extern int mem_cgroup_init(void);
 #else /* CONFIG_MEMCG */
 
 #define MEM_CGROUP_ID_SHIFT	0
@@ -1472,6 +1473,8 @@ static inline u64 cgroup_id_from_mm(struct mm_struct *mm)
 {
 	return 0;
 }
+
+static inline int mem_cgroup_init(void) { return 0; }
 #endif /* CONFIG_MEMCG */
 
 /*
diff --git a/init/main.c b/init/main.c
index 7f0a2a3dbd29..782320da2e88 100644
--- a/init/main.c
+++ b/init/main.c
@@ -50,6 +50,7 @@
 #include <linux/writeback.h>
 #include <linux/cpu.h>
 #include <linux/cpuset.h>
+#include <linux/memcontrol.h>
 #include <linux/cgroup.h>
 #include <linux/efi.h>
 #include <linux/tick.h>
@@ -1087,6 +1088,7 @@ void start_kernel(void)
 	nsfs_init();
 	pidfs_init();
 	cpuset_init();
+	mem_cgroup_init();
 	cgroup_init();
 	taskstats_init_early();
 	delayacct_init();
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e17e0a9ceee0..dcb07a52b4ed 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5042,14 +5042,14 @@ static int __init cgroup_memory(char *s)
 __setup("cgroup.memory=", cgroup_memory);
 
 /*
- * subsys_initcall() for memory controller.
+ * Memory controller init before cgroup_init() initialize root_mem_cgroup.
  *
  * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
  * context because of lock dependencies (cgroup_lock -> cpu hotplug) but
  * basically everything that doesn't depend on a specific mem_cgroup structure
  * should be initialized from here.
  */
-static int __init mem_cgroup_init(void)
+int __init mem_cgroup_init(void)
 {
 	int cpu;
 
@@ -5070,7 +5070,6 @@ static int __init mem_cgroup_init(void)
 
 	return 0;
 }
-subsys_initcall(mem_cgroup_init);
 
 #ifdef CONFIG_SWAP
 /**