3 files changed, 38 insertions, 37 deletions

diff --git a/include/linux/slab.h b/include/linux/slab.h
index c97fe92532d1..c01780540054 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -163,7 +163,12 @@ struct kmem_cache {
 #else /* CONFIG_SLOB */
 
 /*
- * The largest kmalloc size supported by the slab allocators is
+ * Kmalloc array related definitions
+ */
+
+#ifdef CONFIG_SLAB
+/*
+ * The largest kmalloc size supported by the SLAB allocators is
  * 32 megabyte (2^25) or the maximum allocatable page order if that is
  * less than 32 MB.
  *
@@ -173,9 +178,24 @@ struct kmem_cache {
  */
 #define KMALLOC_SHIFT_HIGH      ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
                                 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
+#define KMALLOC_SHIFT_MAX       KMALLOC_SHIFT_HIGH
+#define KMALLOC_SHIFT_LOW       5
+#else
+/*
+ * SLUB allocates up to order 2 pages directly and otherwise
+ * passes the request to the page allocator.
+ */
+#define KMALLOC_SHIFT_HIGH      (PAGE_SHIFT + 1)
+#define KMALLOC_SHIFT_MAX       (MAX_ORDER + PAGE_SHIFT)
+#define KMALLOC_SHIFT_LOW       3
+#endif
 
-#define KMALLOC_MAX_SIZE        (1UL << KMALLOC_SHIFT_HIGH)
-#define KMALLOC_MAX_ORDER       (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
+/* Maximum allocatable size */
+#define KMALLOC_MAX_SIZE        (1UL << KMALLOC_SHIFT_MAX)
+/* Maximum size for which we actually use a slab cache */
+#define KMALLOC_MAX_CACHE_SIZE  (1UL << KMALLOC_SHIFT_HIGH)
+/* Maximum order allocatable via the slab allocagtor */
+#define KMALLOC_MAX_ORDER       (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
 
 /*
  * Kmalloc subsystem.
@@ -183,15 +203,9 @@ struct kmem_cache {
 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
 #else
-#ifdef CONFIG_SLAB
-#define KMALLOC_MIN_SIZE 32
-#else
-#define KMALLOC_MIN_SIZE 8
-#endif
+#define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
 #endif
 
-#define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
-
 /*
  * Figure out which kmalloc slab an allocation of a certain size
  * belongs to.
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 99c3e05ff1f0..032028ef9a34 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -115,19 +115,6 @@ struct kmem_cache {
         struct kmem_cache_node *node[MAX_NUMNODES];
 };
 
-/*
- * Maximum kmalloc object size handled by SLUB. Larger object allocations
- * are passed through to the page allocator. The page allocator "fastpath"
- * is relatively slow so we need this value sufficiently high so that
- * performance critical objects are allocated through the SLUB fastpath.
- *
- * This should be dropped to PAGE_SIZE / 2 once the page allocator
- * "fastpath" becomes competitive with the slab allocator fastpaths.
- */
-#define SLUB_MAX_SIZE (2 * PAGE_SIZE)
-
-#define SLUB_PAGE_SHIFT (PAGE_SHIFT + 2)
-
 #ifdef CONFIG_ZONE_DMA
 #define SLUB_DMA __GFP_DMA
 #else
@@ -139,7 +126,7 @@ struct kmem_cache {
  * We keep the general caches in an array of slab caches that are used for
  * 2^x bytes of allocations.
  */
-extern struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
+extern struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
 
 /*
  * Find the slab cache for a given combination of allocation flags and size.
@@ -211,7 +198,7 @@ static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 {
         if (__builtin_constant_p(size)) {
-                if (size > SLUB_MAX_SIZE)
+                if (size > KMALLOC_MAX_CACHE_SIZE)
                         return kmalloc_large(size, flags);
 
                 if (!(flags & SLUB_DMA)) {
@@ -247,7 +234,7 @@ kmem_cache_alloc_node_trace(struct kmem_cache *s,
 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 {
         if (__builtin_constant_p(size) &&
-                size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
+                size <= KMALLOC_MAX_CACHE_SIZE && !(flags & SLUB_DMA)) {
                         struct kmem_cache *s = kmalloc_slab(size);
 
                 if (!s)
diff --git a/mm/slub.c b/mm/slub.c
index ba2ca53f6c3a..d0f72ee06310 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2775,7 +2775,7 @@ init_kmem_cache_node(struct kmem_cache_node *n)
 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
 {
         BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
-                        SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu));
+                        KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
 
         /*
          * Must align to double word boundary for the double cmpxchg
@@ -3174,11 +3174,11 @@ int __kmem_cache_shutdown(struct kmem_cache *s)
  *              Kmalloc subsystem
  *******************************************************************/
 
-struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
+struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
 EXPORT_SYMBOL(kmalloc_caches);
 
 #ifdef CONFIG_ZONE_DMA
-static struct kmem_cache *kmalloc_dma_caches[SLUB_PAGE_SHIFT];
+static struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1];
 #endif
 
 static int __init setup_slub_min_order(char *str)
@@ -3280,7 +3280,7 @@ void *__kmalloc(size_t size, gfp_t flags)
         struct kmem_cache *s;
         void *ret;
 
-        if (unlikely(size > SLUB_MAX_SIZE))
+        if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
                 return kmalloc_large(size, flags);
 
         s = get_slab(size, flags);
@@ -3316,7 +3316,7 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node)
         struct kmem_cache *s;
         void *ret;
 
-        if (unlikely(size > SLUB_MAX_SIZE)) {
+        if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
                 ret = kmalloc_large_node(size, flags, node);
 
                 trace_kmalloc_node(_RET_IP_, ret,
@@ -3721,7 +3721,7 @@ void __init kmem_cache_init(void)
                 caches++;
         }
 
-        for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
+        for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
                 kmalloc_caches[i] = create_kmalloc_cache("kmalloc", 1 << i, 0);
                 caches++;
         }
@@ -3739,7 +3739,7 @@ void __init kmem_cache_init(void)
                 BUG_ON(!kmalloc_caches[2]->name);
         }
 
-        for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
+        for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
                 char *s = kasprintf(GFP_NOWAIT, "kmalloc-%d", 1 << i);
 
                 BUG_ON(!s);
@@ -3751,7 +3751,7 @@ void __init kmem_cache_init(void)
 #endif
 
 #ifdef CONFIG_ZONE_DMA
-        for (i = 0; i < SLUB_PAGE_SHIFT; i++) {
+        for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
                 struct kmem_cache *s = kmalloc_caches[i];
 
                 if (s && s->size) {
@@ -3930,7 +3930,7 @@ void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
         struct kmem_cache *s;
         void *ret;
 
-        if (unlikely(size > SLUB_MAX_SIZE))
+        if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
                 return kmalloc_large(size, gfpflags);
 
         s = get_slab(size, gfpflags);
@@ -3953,7 +3953,7 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
         struct kmem_cache *s;
         void *ret;
 
-        if (unlikely(size > SLUB_MAX_SIZE)) {
+        if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
                 ret = kmalloc_large_node(size, gfpflags, node);
 
                 trace_kmalloc_node(caller, ret,
@@ -4312,7 +4312,7 @@ static void resiliency_test(void)
 {
         u8 *p;
 
-        BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || SLUB_PAGE_SHIFT < 10);
+        BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
 
         printk(KERN_ERR "SLUB resiliency testing\n");
         printk(KERN_ERR "-----------------------\n");