Index: linux-2.6.21-rc3/include/linux/slab.h
===================================================================
--- linux-2.6.21-rc3.orig/include/linux/slab.h	2007-03-07 22:17:25.000000000 -0800
+++ linux-2.6.21-rc3/include/linux/slab.h	2007-03-07 22:21:58.000000000 -0800
@@ -33,11 +33,14 @@
 #define SLAB_DESTROY_BY_RCU	0x00080000UL	/* Defer freeing slabs to RCU */
 #define SLAB_MEM_SPREAD		0x00100000UL	/* Spread some memory over cpuset */
 #define SLAB_TRACE		0x00200000UL	/* Trace allocations and frees */
+#define SLAB_DEFRAG		0x00400000UL	/* DTOR is function for object removal */
 
 /* Flags passed to a constructor functions */
 #define SLAB_CTOR_CONSTRUCTOR	0x001UL		/* If not set, then deconstructor */
 #define SLAB_CTOR_ATOMIC	0x002UL		/* Tell constructor it can't sleep */
 #define SLAB_CTOR_VERIFY	0x004UL		/* Tell constructor it's a verify call */
+#define SLAB_DTOR_DESTRUCTOR	0x001UL		/* DTOR called for object destruct */
+#define SLAB_DTOR_FREE		0x002UL		/* DTOR called for object removal */
 
 /*
  * struct kmem_cache related prototypes
Index: linux-2.6.21-rc3/mm/slub.c
===================================================================
--- linux-2.6.21-rc3.orig/mm/slub.c	2007-03-07 22:20:07.000000000 -0800
+++ linux-2.6.21-rc3/mm/slub.c	2007-03-08 10:17:05.000000000 -0800
@@ -597,7 +597,7 @@
 		void *start = page_address(page);
 		void *end = start + (pages << PAGE_SHIFT);
 		void *p;
-		int mode = 1;
+		int mode = SLAB_CTOR_CONSTRUCTOR;
 
 		if (!(flags & __GFP_WAIT))
 			mode |= SLAB_CTOR_ATOMIC;
@@ -680,7 +680,7 @@
 
 		for (p = start; p <= end - s->size; p += s->size) {
 			if (s->dtor)
-				s->dtor(p, s, 0);
+				s->dtor(p, s, SLAB_DTOR_DESTRUCTOR);
 			else
 				check_object(s, page, p, 0);
 		}
@@ -2181,12 +2181,68 @@
 #endif
 
 /***************************************************************
- *	Compatiblility definitions
+ *	Shrink Cache Support
  **************************************************************/
 
+static void attempt_to_free_objects(struct kmem_cache *s, struct page *page)
+{
+	/* on the sparsely populated attempt to free all objects */
+	dtor(s, SLAB_DTOR_FREE);
+}
+
+static void shrink_node(struct kmem_cache *s, struct kmem_cache_node *n)
+{
+	LIST_HEAD(list);
+	struct page *page;
+	struct page *page2;
+
+	/*
+	 * First loop to extract candidate slabs from the
+	 * partial lists.
+	 */
+	spin_lock_irq(&n->list_lock);
+	list_for_each_entry_safe(page, page2, &n->partial, lru) {
+		if (page->inuse < s->objects / 3) {
+			if (slab_trylock(page)) {
+				SetPageActive(page);
+				list_move(&page->lru, &list);
+				slab_unlock(page);
+			}
+		}
+	}
+	spin_unlock_irq(&n->list_lock);
+
+	/* Do the actual freeing */
+	list_for_each_entry(page, &list, lru)
+		attempt_to_free_objects(page);
+
+	/* Return slabs to the partial list */
+	list_for_each_entry_safe(page, page2, &list, lru) {
+		list_del(&page->lru);
+		slab_lock(page);
+		ClearPageActive(page);
+		putback_slab(s, page);
+	}
+}
+
 int kmem_cache_shrink(struct kmem_cache *s)
 {
+	int node;
+
 	flush_all(s);
+	if (!(s->flags & SLAB_DEFRAG) || s->objects < 4)
+		return 0;
+
+	for_each_online_node(node) {
+		struct kmem_cache_node *n = s->node[node];
+
+		if (node != numa_node_id())
+		if (n->nr_partial < 5)
+			inc some counter;
+			queue_delayed_work_on(first_cpu(node_to_cpumask(node)), shrink_node);
+	}
+	shrink_node(s);
+	/*	wait till complete; */
 	return 0;
 }
 EXPORT_SYMBOL(kmem_cache_shrink);
Index: linux-2.6.21-rc3/include/linux/slub_def.h
===================================================================
--- linux-2.6.21-rc3.orig/include/linux/slub_def.h	2007-03-07 22:35:04.000000000 -0800
+++ linux-2.6.21-rc3/include/linux/slub_def.h	2007-03-07 23:31:49.000000000 -0800
@@ -15,6 +15,7 @@
 	unsigned long nr_partial;
 	atomic_long_t nr_slabs;
 	struct list_head partial;
+	struct delayed_work work;
 };
 
 /*
@@ -36,6 +37,7 @@
 	const char *name;	/* Name (only for display!) */
 	char *aliases;		/* Slabs merged into this one */
 	struct list_head list;	/* List of slabs */
+	struct mutex nodework;	/* Per node work queued */
 #ifdef CONFIG_SMP
 	struct mutex flushing;
 	atomic_t cpu_slabs;	/*