mm: memcontrol: move kmem accounting code to CONFIG_MEMCG

The cgroup2 memory controller will account important in-kernel memory
consumers per default.  Move all necessary components to CONFIG_MEMCG.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index 33d0490..cf139d3 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -69,7 +69,8 @@
 	 */
 	int obj_offset;
 #endif /* CONFIG_DEBUG_SLAB */
-#ifdef CONFIG_MEMCG_KMEM
+
+#ifdef CONFIG_MEMCG
 	struct memcg_cache_params memcg_params;
 #endif