slab: remove kmem_bufctl_t

Now, we changed the management method of free objects of the slab and
there is no need to use special value, BUFCTL_END, BUFCTL_FREE and
BUFCTL_ACTIVE. So remove them.

Acked-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Pekka Enberg <penberg@iki.fi>

1 files changed, 11 insertions, 31 deletions

diff --git a/mm/slab.c b/mm/slab.c
index 05fe37eb4a57..6ced1ccf8abb 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -163,27 +163,7 @@
  */
 static bool pfmemalloc_active __read_mostly;
 
-/*
- * kmem_bufctl_t:
- *
- * Bufctl's are used for linking objs within a slab
- * linked offsets.
- *
- * This implementation relies on "struct page" for locating the cache &
- * slab an object belongs to.
- * This allows the bufctl structure to be small (one int), but limits
- * the number of objects a slab (not a cache) can contain when off-slab
- * bufctls are used. The limit is the size of the largest general cache
- * that does not use off-slab slabs.
- * For 32bit archs with 4 kB pages, is this 56.
- * This is not serious, as it is only for large objects, when it is unwise
- * to have too many per slab.
- * Note: This limit can be raised by introducing a general cache whose size
- * is less than 512 (PAGE_SIZE<<3), but greater than 256.
- */
-
-typedef unsigned int kmem_bufctl_t;
-#define SLAB_LIMIT      (((kmem_bufctl_t)(~0U))-3)
+#define SLAB_LIMIT      (((unsigned int)(~0U))-1)
 
 /*
  * struct slab
@@ -197,7 +177,7 @@ struct slab {
                 struct list_head list;
                 void *s_mem;            /* including colour offset */
                 unsigned int inuse;     /* num of objs active in slab */
-                kmem_bufctl_t free;
+                unsigned int free;
         };
 };
 
@@ -613,7 +593,7 @@ static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
 
 static size_t slab_mgmt_size(size_t nr_objs, size_t align)
 {
-        return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align);
+        return ALIGN(sizeof(struct slab)+nr_objs*sizeof(unsigned int), align);
 }
 
 /*
@@ -633,7 +613,7 @@ static void cache_estimate(unsigned long gfporder, size_t buffer_size,
          * slab is used for:
          *
          * - The struct slab
-         * - One kmem_bufctl_t for each object
+         * - One unsigned int for each object
          * - Padding to respect alignment of @align
          * - @buffer_size bytes for each object
          *
@@ -658,7 +638,7 @@ static void cache_estimate(unsigned long gfporder, size_t buffer_size,
                  * into account.
                  */
                 nr_objs = (slab_size - sizeof(struct slab)) /
-                          (buffer_size + sizeof(kmem_bufctl_t));
+                          (buffer_size + sizeof(unsigned int));
 
                 /*
                  * This calculated number will be either the right
@@ -2068,7 +2048,7 @@ static size_t calculate_slab_order(struct kmem_cache *cachep,
                          * looping condition in cache_grow().
                          */
                         offslab_limit = size - sizeof(struct slab);
-                        offslab_limit /= sizeof(kmem_bufctl_t);
+                        offslab_limit /= sizeof(unsigned int);
 
                         if (num > offslab_limit)
                                 break;
@@ -2309,7 +2289,7 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
         if (!cachep->num)
                 return -E2BIG;
 
-        slab_size = ALIGN(cachep->num * sizeof(kmem_bufctl_t)
+        slab_size = ALIGN(cachep->num * sizeof(unsigned int)
                           + sizeof(struct slab), cachep->align);
 
         /*
@@ -2324,7 +2304,7 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
         if (flags & CFLGS_OFF_SLAB) {
                 /* really off slab. No need for manual alignment */
                 slab_size =
-                    cachep->num * sizeof(kmem_bufctl_t) + sizeof(struct slab);
+                    cachep->num * sizeof(unsigned int) + sizeof(struct slab);
 
 #ifdef CONFIG_PAGE_POISONING
                 /* If we're going to use the generic kernel_map_pages()
@@ -2603,9 +2583,9 @@ static struct slab *alloc_slabmgmt(struct kmem_cache *cachep,
         return slabp;
 }
 
-static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp)
+static inline unsigned int *slab_bufctl(struct slab *slabp)
 {
-        return (kmem_bufctl_t *) (slabp + 1);
+        return (unsigned int *) (slabp + 1);
 }
 
 static void cache_init_objs(struct kmem_cache *cachep,
@@ -2684,7 +2664,7 @@ static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp,
 {
         unsigned int objnr = obj_to_index(cachep, slabp, objp);
 #if DEBUG
-        kmem_bufctl_t i;
+        unsigned int i;
 
         /* Verify that the slab belongs to the intended node */
         WARN_ON(page_to_nid(virt_to_page(objp)) != nodeid);