diff --git a/include/linux/slab.h b/include/linux/slab.h
index 2e3b448..1e03c11 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -473,14 +473,14 @@
 #ifndef ARCH_SLAB_MINALIGN
 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
 #endif
+
+struct memcg_cache_array {
+	struct rcu_head rcu;
+	struct kmem_cache *entries[0];
+};
+
 /*
  * This is the main placeholder for memcg-related information in kmem caches.
- * struct kmem_cache will hold a pointer to it, so the memory cost while
- * disabled is 1 pointer. The runtime cost while enabled, gets bigger than it
- * would otherwise be if that would be bundled in kmem_cache: we'll need an
- * extra pointer chase. But the trade off clearly lays in favor of not
- * penalizing non-users.
- *
  * Both the root cache and the child caches will have it. For the root cache,
  * this will hold a dynamically allocated array large enough to hold
  * information about the currently limited memcgs in the system. To allow the
@@ -495,10 +495,7 @@
 struct memcg_cache_params {
 	bool is_root_cache;
 	union {
-		struct {
-			struct rcu_head rcu_head;
-			struct kmem_cache *memcg_caches[0];
-		};
+		struct memcg_cache_array __rcu *memcg_caches;
 		struct {
 			struct mem_cgroup *memcg;
 			struct kmem_cache *root_cache;