Merge branch 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux

Pull slab changes from Pekka Enberg:
 "The biggest change is byte-sized freelist indices which reduces slab
  freelist memory usage:

    https://lkml.org/lkml/2013/12/2/64"

* 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
  mm: slab/slub: use page->list consistently instead of page->lru
  mm/slab.c: cleanup outdated comments and unify variables naming
  slab: fix wrongly used macro
  slub: fix high order page allocation problem with __GFP_NOFAIL
  slab: Make allocations with GFP_ZERO slightly more efficient
  slab: make more slab management structure off the slab
  slab: introduce byte sized index for the freelist of a slab
  slab: restrict the number of objects in a slab
  slab: introduce helper functions to get/set free object
  slab: factor out calculate nr objects in cache_estimate

1 files changed, 11 insertions, 0 deletions

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 3dd389aa91c7c..307bfbe62387a 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -242,6 +242,17 @@ struct kmem_cache {
 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
 #endif
 
+/*
+ * This restriction comes from byte sized index implementation.
+ * Page size is normally 2^12 bytes and, in this case, if we want to use
+ * byte sized index which can represent 2^8 entries, the size of the object
+ * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
+ * If minimum size of kmalloc is less than 16, we use it as minimum object
+ * size and give up to use byte sized index.
+ */
+#define SLAB_OBJ_MIN_SIZE      (KMALLOC_MIN_SIZE < 16 ? \
+                               (KMALLOC_MIN_SIZE) : 16)
+
 #ifndef CONFIG_SLOB
 extern struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
 #ifdef CONFIG_ZONE_DMA