slub: Drop fallback to page allocator method

There is now a generic method of falling back to a slab page of minimal
order. No need anymore for the fallback to kmalloc_large().
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>

mm/slub.c

@@ -204,8 +204,6 @@ static inline void ClearSlabDebug(struct page *page)
 /* Internal SLUB flags */
 #define __OBJECT_POISON		0x80000000 /* Poison object */
 #define __SYSFS_ADD_DEFERRED	0x40000000 /* Not yet visible via sysfs */
-#define __KMALLOC_CACHE		0x20000000 /* objects freed using kfree */
-#define __PAGE_ALLOC_FALLBACK	0x10000000 /* Allow fallback to page alloc */
 
 /* Not all arches define cache_line_size */
 #ifndef cache_line_size
@@ -1623,27 +1621,6 @@ static void *__slab_alloc(struct kmem_cache *s,
 		c->page = new;
 		goto load_freelist;
 	}
-
-	/*
-	 * No memory available.
-	 *
-	 * If the slab uses higher order allocs but the object is
-	 * smaller than a page size then we can fallback in emergencies
-	 * to the page allocator via kmalloc_large. The page allocator may
-	 * have failed to obtain a higher order page and we can try to
-	 * allocate a single page if the object fits into a single page.
-	 * That is only possible if certain conditions are met that are being
-	 * checked when a slab is created.
-	 */
-	if (!(gfpflags & __GFP_NORETRY) &&
-				(s->flags & __PAGE_ALLOC_FALLBACK)) {
-		if (gfpflags & __GFP_WAIT)
-			local_irq_enable();
-		object = kmalloc_large(s->objsize, gfpflags);
-		if (gfpflags & __GFP_WAIT)
-			local_irq_disable();
-		return object;
-	}
 	return NULL;
 debug:
 	if (!alloc_debug_processing(s, c->page, object, addr))
@@ -2330,20 +2307,7 @@ static int calculate_sizes(struct kmem_cache *s)
 	 */
 	size = ALIGN(size, align);
 	s->size = size;
-
-	if ((flags & __KMALLOC_CACHE) &&
-			PAGE_SIZE / size < slub_min_objects) {
-		/*
-		 * Kmalloc cache that would not have enough objects in
-		 * an order 0 page. Kmalloc slabs can fallback to
-		 * page allocator order 0 allocs so take a reasonably large
-		 * order that will allows us a good number of objects.
-		 */
-		order = max(slub_max_order, PAGE_ALLOC_COSTLY_ORDER);
-		s->flags |= __PAGE_ALLOC_FALLBACK;
-		s->allocflags |= __GFP_NOWARN;
-	} else
-		order = calculate_order(size);
+	order = calculate_order(size);
 
 	if (order < 0)
 		return 0;
@@ -2589,7 +2553,7 @@ static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s,
 
 	down_write(&slub_lock);
 	if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN,
-			flags | __KMALLOC_CACHE, NULL))
+								flags, NULL))
 		goto panic;
 
 	list_add(&s->list, &slab_caches);
@@ -3105,9 +3069,6 @@ static int slab_unmergeable(struct kmem_cache *s)
 	if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
 		return 1;
 
-	if ((s->flags & __PAGE_ALLOC_FALLBACK))
-		return 1;
-
 	if (s->ctor)
 		return 1;