---
 Documentation/vm/slabinfo.c |    7 +++++++
 include/linux/slub_def.h    |    2 ++
 mm/slub.c                   |   29 ++++++++++++++++++++---------
 3 files changed, 29 insertions(+), 9 deletions(-)

Index: linux-2.6/include/linux/slub_def.h
===================================================================
--- linux-2.6.orig/include/linux/slub_def.h	2008-03-27 16:50:34.344612794 -0700
+++ linux-2.6/include/linux/slub_def.h	2008-03-27 16:51:11.668894552 -0700
@@ -30,6 +30,8 @@ enum stat_item {
 	DEACTIVATE_TO_TAIL,	/* Cpu slab was moved to the tail of partials */
 	DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
 	ORDER_FALLBACK,		/* Number of times fallback was necessary */
+	CONTENTION_ALLOC,	/* slab lock contention on alloc */
+	CONTENTION_FREE,	/* slab lock contention on free */
 	NR_SLUB_STAT_ITEMS };
 
 struct kmem_cache_cpu {
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c	2008-03-27 16:51:18.556946456 -0700
+++ linux-2.6/mm/slub.c	2008-03-27 17:16:34.405210283 -0700
@@ -1210,11 +1210,6 @@ static void discard_slab(struct kmem_cac
 /*
  * Per slab locking using the pagelock
  */
-static __always_inline void slab_lock(struct page *page)
-{
-	bit_spin_lock(PG_locked, &page->flags);
-}
-
 static __always_inline void slab_unlock(struct page *page)
 {
 	__bit_spin_unlock(PG_locked, &page->flags);
@@ -1228,6 +1223,17 @@ static __always_inline int slab_trylock(
 	return rc;
 }
 
+static __always_inline void slab_lock(struct page *page,
+				struct kmem_cache_cpu *c, int counter)
+{
+#ifdef CONFIG_SLUB_STATS
+	if (slab_trylock(page))
+		return;
+	stat(c, counter);
+#endif
+	bit_spin_lock(PG_locked, &page->flags);
+}
+
 /*
  * Management of partially allocated slabs
  */
@@ -1444,7 +1450,8 @@ static void deactivate_slab(struct kmem_
 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
 {
 	stat(c, CPUSLAB_FLUSH);
-	slab_lock(c->page);
+	slab_lock(c->page, get_cpu_slab(s, raw_smp_processor_id()),
+							CONTENTION_FREE);
 	deactivate_slab(s, c);
 }
 
@@ -1521,7 +1528,7 @@ static void *__slab_alloc(struct kmem_ca
 	if (!c->page)
 		goto new_slab;
 
-	slab_lock(c->page);
+	slab_lock(c->page, c, CONTENTION_ALLOC);
 	if (unlikely(!node_match(c, node)))
 		goto another_slab;
 
@@ -1567,7 +1574,7 @@ new_slab:
 		stat(c, ALLOC_SLAB);
 		if (c->page)
 			flush_slab(s, c);
-		slab_lock(new);
+		slab_lock(new, c, CONTENTION_ALLOC);
 		SetSlabFrozen(new);
 		c->page = new;
 		goto load_freelist;
@@ -1650,7 +1657,7 @@ static void __slab_free(struct kmem_cach
 
 	c = get_cpu_slab(s, raw_smp_processor_id());
 	stat(c, FREE_SLOWPATH);
-	slab_lock(page);
+	slab_lock(page, c, CONTENTION_FREE);
 
 	if (unlikely(SlabDebug(page)))
 		goto debug;
@@ -4085,6 +4092,8 @@ STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate
 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
 STAT_ATTR(ORDER_FALLBACK, order_fallback);
+STAT_ATTR(CONTENTION_ALLOC, contention_alloc);
+STAT_ATTR(CONTENTION_FREE, contention_free);
 #endif
 
 static struct attribute *slab_attrs[] = {
@@ -4138,6 +4147,8 @@ static struct attribute *slab_attrs[] = 
 	&deactivate_to_tail_attr.attr,
 	&deactivate_remote_frees_attr.attr,
 	&order_fallback_attr.attr,
+	&contention_alloc_attr.attr,
+	&contention_free_attr.attr,
 #endif
 	NULL
 };
Index: linux-2.6/Documentation/vm/slabinfo.c
===================================================================
--- linux-2.6.orig/Documentation/vm/slabinfo.c	2008-03-27 16:56:05.658879168 -0700
+++ linux-2.6/Documentation/vm/slabinfo.c	2008-03-27 16:58:24.555685606 -0700
@@ -34,6 +34,7 @@ struct slabinfo {
 	unsigned long partial, objects, slabs, objects_partial, objects_total;
 	unsigned long alloc_fastpath, alloc_slowpath;
 	unsigned long free_fastpath, free_slowpath;
+	unsigned long contention_free, contention_alloc;
 	unsigned long free_frozen, free_add_partial, free_remove_partial;
 	unsigned long alloc_from_partial, alloc_slab, free_slab, alloc_refill;
 	unsigned long cpuslab_flush, deactivate_full, deactivate_empty;
@@ -430,6 +431,10 @@ void slab_stats(struct slabinfo *s)
 	printf("\n");
 	printf("Slab Perf Counter       Alloc     Free %%Al %%Fr\n");
 	printf("--------------------------------------------------\n");
+	printf("Contention             %8lu %8lu %3lu %3lu\n",
+		s->contention_alloc, s->contention_free,
+		s->contention_alloc * 100 / total_alloc,
+		s->contention_free * 100 / total_free);
 	printf("Fastpath             %8lu %8lu %3lu %3lu\n",
 		s->alloc_fastpath, s->free_fastpath,
 		s->alloc_fastpath * 100 / total_alloc,
@@ -1175,6 +1180,8 @@ void read_slab_dir(void)
 			slab->alloc_slowpath = get_obj("alloc_slowpath");
 			slab->free_fastpath = get_obj("free_fastpath");
 			slab->free_slowpath = get_obj("free_slowpath");
+			slab->contention_free = get_obj("contention_free");
+			slab->contention_alloc = get_obj("contention_alloc");
 			slab->free_frozen= get_obj("free_frozen");
 			slab->free_add_partial = get_obj("free_add_partial");
 			slab->free_remove_partial = get_obj("free_remove_partial");