Index: linux-2.6.21-rc1/mm/slub.c
===================================================================
--- linux-2.6.21-rc1.orig/mm/slub.c	2007-02-24 13:07:42.000000000 -0800
+++ linux-2.6.21-rc1/mm/slub.c	2007-02-24 13:08:10.000000000 -0800
@@ -69,10 +69,15 @@
 /*
  * Set of flags that will prohibit slab merging
  */
-#define SLUB_NO_MERGE (SLAB_RECLAIM_ACCOUNT | SLAB_DESTROY_BY_RCU | \
-	SLAB_CACHE_DMA | SLAB_DEBUG_FREE | SLAB_DEBUG_INITIAL | \
+#define SLUB_NEVER_MERGE (SLAB_DEBUG_FREE | SLAB_DEBUG_INITIAL | \
 	SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
 
+/*
+ * Set of flags that must be the same for merging
+ */
+#define SLUB_SAME_MERGE (SLAB_RECLAIM_ACCOUNT | SLAB_DESTROY_BY_RCU | \
+	SLAB_CACHE_DMA)
+
 #ifndef ARCH_KMALLOC_MINALIGN
 #define ARCH_KMALLOC_MINALIGN sizeof(void *)
 #endif
@@ -91,6 +96,10 @@
 static struct notifier_block slab_notifier;
 #endif
 
+static DECLARE_RWSEM(slabstat_sem);
+
+LIST_HEAD(slab_caches);
+
 /********************************************************************
  * 			Core slab cache functions
  *******************************************************************/
@@ -1281,20 +1290,53 @@
 #endif
 }
 
-static struct kmem_cache *kmem_cache_dup(struct kmem_cache *s)
+static struct kmem_cache *kmem_cache_dup(struct kmem_cache *s,
+						const char *name)
 {
+	char *x;
+
 	atomic_inc(&s->refcount);
+
+	if (!s->aliases)
+		s->aliases = kstrdup(name, GFP_KERNEL);
+	else {
+		x = kmalloc(strlen(s->aliases) + strlen(name) + 1,
+						GFP_KERNEL);
+		strcpy(x, s->aliases);
+		strcat(x, " ");
+		strcat(x, name);
+		kfree(s->aliases);
+		s->aliases = x;
+	}
 	return s;
 }
 
 
-static struct kmem_cache *__kmalloc_slab(size_t size)
+/*
+ * Find a mergeable slab cache
+ */
+static struct kmem_cache *find_mergeable(unsigned long size, unsigned long flags)
 {
-	int index = kmalloc_index(size) - KMALLOC_SHIFT_LOW;
+	struct list_head *h;
 
-	if (index < 0)
+	if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
 		return NULL;
-	return &kmalloc_caches[index];
+
+	down_read(&slabstat_sem);
+	list_for_each(h, &slab_caches) {
+		struct kmem_cache *s =
+			container_of(h, struct kmem_cache, list);
+
+		if (s->size >= size &&
+				s->size - size <= sizeof(void *) &&
+				((flags & SLUB_SAME_MERGE) ==
+				(s->flags & SLUB_SAME_MERGE))) {
+			up_read(&slabstat_sem);
+			return s;
+		}
+	}
+	up_read(&slabstat_sem);
+	return NULL;
 }
 
 struct kmem_cache *kmem_cache_create(const char *name, size_t size,
@@ -1302,29 +1344,18 @@
 		void (*ctor)(void *, struct kmem_cache *, unsigned long),
 		void (*dtor)(void *, struct kmem_cache *, unsigned long))
 {
-	struct kmem_cache *s;
-
-	if (!slub_nomerge && !ctor && !dtor && !(flags & SLUB_NO_MERGE) &&
-			align <= ARCH_SLAB_MINALIGN) {
-		int sz = ALIGN(size, calculate_alignment(flags, align));
-
-		/* Find the kmalloc slab that would be used for this size */
-		s = __kmalloc_slab(sz);
-		if (!s)
-			return NULL;
+	struct kmem_cache *s = NULL;
 
-		/*
-		 * Check if there would be less than a word difference
-		 * between the size of the slab and the kmalloc slab.
-		 * If so then just use the kmalloc array and avoid creating
-		 * a new slab.
-		 */
-		if (s->size - sz <= sizeof(void *)) {
-			printk(KERN_INFO "SLUB: Merging slab_cache %s size %d"
-				" into kmalloc array size %d\n",
-				name, (int)size, (int)s->size);
-			return kmem_cache_dup(s);
-		}
+	if (!ctor && !dtor)
+		s = find_mergeable(
+			ALIGN(size, calculate_alignment(flags, align)),
+			flags);
+
+	if (s) {
+		printk(KERN_INFO "SLUB: Merging slab_cache %s size %d"
+			" with slab_cache %s\n",
+			name, (int)size, s->name);
+		return kmem_cache_dup(s, name);
 	}
 
 	s = kmalloc(sizeof(struct kmem_cache), GFP_KERNEL);
@@ -1354,10 +1385,6 @@
  *			Slab proc interface
  *******************************************************************/
 
-static DECLARE_RWSEM(slabstat_sem);
-
-LIST_HEAD(slab_caches);
-
 void for_all_slabs(void (*func)(struct kmem_cache *, int), int cpu)
 {
 	struct list_head *h;
@@ -1367,7 +1394,7 @@
 		struct kmem_cache *s =
 			container_of(h, struct kmem_cache, list);
 
-	func(s, cpu);
+		func(s, cpu);
 	}
 	up_read(&slabstat_sem);
 }
@@ -1492,6 +1519,10 @@
 
 	kfree(x);
 	display_nodes(m, nodes);
+	if (s->aliases) {
+		seq_putc(m, ' ');
+		seq_puts(m, s->aliases);
+	}
 	seq_putc(m, '\n');
 	return 0;
 }
Index: linux-2.6.21-rc1/include/linux/slub_def.h
===================================================================
--- linux-2.6.21-rc1.orig/include/linux/slub_def.h	2007-02-24 13:08:00.000000000 -0800
+++ linux-2.6.21-rc1/include/linux/slub_def.h	2007-02-24 13:08:13.000000000 -0800
@@ -33,6 +33,7 @@
 	int objsize;		/* The size of an object that is in a chunk */
 	int inuse;		/* Used portion of the chunk */
 	const char *name;	/* Name (only for display!) */
+	char *aliases;		/* Slabs merged into this one */
 	struct list_head list;	/* List of slabs */
 #ifdef CONFIG_SMP
 	struct mutex flushing;