On 07/25/2012 10:10 PM, Kirill A. Shutemov wrote:

On Wed, Jul 25, 2012 at 06:38:13PM +0400, Glauber Costa wrote:

...

quoted

@@ -337,6 +341,12 @@ extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
 	__kmalloc(size, flags)
 #endif /* DEBUG_SLAB */
 
+#ifdef CONFIG_MEMCG_KMEM
+#define MAX_KMEM_CACHE_TYPES 400
+#else
+#define MAX_KMEM_CACHE_TYPES 0
+#endif /* CONFIG_MEMCG_KMEM */
+
 #ifdef CONFIG_NUMA
 /*
  * kmalloc_node_track_caller is a special version of kmalloc_node that

...

quoted

@@ -527,6 +532,24 @@ static inline bool memcg_kmem_enabled(struct mem_cgroup *memcg)
 		memcg->kmem_accounted;
 }
 
+struct ida cache_types;
+
+void memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *cachep)
+{
+	int id = -1;
+
+	if (!memcg)
+		id = ida_simple_get(&cache_types, 0, MAX_KMEM_CACHE_TYPES,
+				    GFP_KERNEL);

MAX_KMEM_CACHE_TYPES is 0 if CONFIG_MEMCG_KMEM undefined.
If 'end' parameter of ida_simple_get() is 0 it will use default max value
which is 0x80000000.
I guess you want MAX_KMEM_CACHE_TYPES to be 1 for !CONFIG_MEMCG_KMEM.

ida_simple_get will not, and should never be called for !CONFIG_MEMCG_KMEM.