---
 include/linux/slub_def.h |    3 ++-
 mm/slub.c                |    7 ++++---
 2 files changed, 6 insertions(+), 4 deletions(-)

Index: linux-2.6/include/linux/slub_def.h
===================================================================
--- linux-2.6.orig/include/linux/slub_def.h	2008-02-06 21:16:41.553735936 -0800
+++ linux-2.6/include/linux/slub_def.h	2008-02-06 21:17:54.440557180 -0800
@@ -15,8 +15,9 @@ struct kmem_cache_cpu {
 	unsigned long freemap;	/* Bitmap of free objects */
 	struct page *page;	/* The slab from which we are allocating */
 	void *address;		/* Page address */
-	unsigned int size;	/* Slab size */
 	int node;		/* The node of the page (or -1 for debug) */
+	unsigned int size;	/* Slab size */
+	u32 recip_val;		/* Reciprocal division value */
 	unsigned int objsize;	/* Size of an object (from kmem_cache) */
 };
 
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c	2008-02-06 21:17:57.312509680 -0800
+++ linux-2.6/mm/slub.c	2008-02-06 22:03:49.287617682 -0800
@@ -21,6 +21,7 @@
 #include <linux/ctype.h>
 #include <linux/kallsyms.h>
 #include <linux/memory.h>
+#include <linux/reciprocal_div.h>
 
 /*
  * Lock order:
@@ -1626,12 +1627,11 @@ static __always_inline void slab_free(st
 	unsigned long flags;
 	struct kmem_cache_cpu *c;
 	int index;
-	unsigned long offset;
+	unsigned long offset = object - page->address;
 
 	local_irq_save(flags);
 	c = get_cpu_slab(s, smp_processor_id());
-	offset = object - page->address;
-	index = offset / c->size;
+	index = reciprocal_divide(offset, c->recip_val);
 //	debug_check_no_locks_freed(x, s->objsize);
 	if (likely(page == c->page && c->node >= 0))
 		__set_bit(index, &c->freemap);
@@ -1819,6 +1819,7 @@ static void init_kmem_cache_cpu(struct k
 	c->node = 0;
 	c->objsize = s->objsize;
 	c->size = s->size;
+	c->recip_val = reciprocal_value(s->size);
 }
 
 static void init_kmem_cache_node(struct kmem_cache_node *n)