SLUB: cleanup - define macros instead of hardcoded numbers

Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Acked-by: NChristoph Lameter <cl@linux-foundation.org>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>

mm/slub.c

@@ -153,6 +153,10 @@
 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
 #endif
 
+#define OO_SHIFT	16
+#define OO_MASK		((1 << OO_SHIFT) - 1)
+#define MAX_OBJS_PER_PAGE	65535 /* since page.objects is u16 */
+
 /* Internal SLUB flags */
 #define __OBJECT_POISON		0x80000000 /* Poison object */
 #define __SYSFS_ADD_DEFERRED	0x40000000 /* Not yet visible via sysfs */
@@ -290,7 +294,7 @@ static inline struct kmem_cache_order_objects oo_make(int order,
 						unsigned long size)
 {
 	struct kmem_cache_order_objects x = {
-		(order << 16) + (PAGE_SIZE << order) / size
+		(order << OO_SHIFT) + (PAGE_SIZE << order) / size
 	};
 
 	return x;
@@ -298,12 +302,12 @@ static inline struct kmem_cache_order_objects oo_make(int order,
 
 static inline int oo_order(struct kmem_cache_order_objects x)
 {
-	return x.x >> 16;
+	return x.x >> OO_SHIFT;
 }
 
 static inline int oo_objects(struct kmem_cache_order_objects x)
 {
-	return x.x & ((1 << 16) - 1);
+	return x.x & OO_MASK;
 }
 
 #ifdef CONFIG_SLUB_DEBUG
@@ -764,8 +768,8 @@ static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
 	}
 
 	max_objects = (PAGE_SIZE << compound_order(page)) / s->size;
-	if (max_objects > 65535)
-		max_objects = 65535;
+	if (max_objects > MAX_OBJS_PER_PAGE)
+		max_objects = MAX_OBJS_PER_PAGE;
 
 	if (page->objects != max_objects) {
 		slab_err(s, page, "Wrong number of objects. Found %d but "
@@ -1807,8 +1811,8 @@ static inline int slab_order(int size, int min_objects,
 	int rem;
 	int min_order = slub_min_order;
 
-	if ((PAGE_SIZE << min_order) / size > 65535)
-		return get_order(size * 65535) - 1;
+	if ((PAGE_SIZE << min_order) / size > MAX_OBJS_PER_PAGE)
+		return get_order(size * MAX_OBJS_PER_PAGE) - 1;
 
 	for (order = max(min_order,
 				fls(min_objects * size - 1) - PAGE_SHIFT);