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Diffstat (limited to 'include/linux/slub_def.h')
-rw-r--r--include/linux/slub_def.h19
1 files changed, 16 insertions, 3 deletions
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 6b657f7dcb2b..9e3a575b2c30 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -122,10 +122,23 @@ struct kmem_cache {
#define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
/*
+ * 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 (PAGE_SIZE)
+
+#define SLUB_PAGE_SHIFT (PAGE_SHIFT + 1)
+
+/*
* 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[PAGE_SHIFT + 1];
+extern struct kmem_cache kmalloc_caches[SLUB_PAGE_SHIFT];
/*
* Sorry that the following has to be that ugly but some versions of GCC
@@ -231,7 +244,7 @@ static __always_inline void *kmalloc(size_t size, gfp_t flags)
void *ret;
if (__builtin_constant_p(size)) {
- if (size > PAGE_SIZE)
+ if (size > SLUB_MAX_SIZE)
return kmalloc_large(size, flags);
if (!(flags & SLUB_DMA)) {
@@ -275,7 +288,7 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
void *ret;
if (__builtin_constant_p(size) &&
- size <= PAGE_SIZE && !(flags & SLUB_DMA)) {
+ size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
struct kmem_cache *s = kmalloc_slab(size);
if (!s)