Subject: Slab defrag: Log information to the syslog to show defrag operations

Dump information into the syslog during defragmentation actions to show that
something is occurring and what effect it has.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

---
 mm/slub.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c	2007-07-29 15:41:21.000000000 -0700
+++ linux-2.6/mm/slub.c	2007-07-29 15:43:17.000000000 -0700
@@ -2599,6 +2599,8 @@ static unsigned long sort_partial_list(s
 	return freed;
 }
 
+#define NR_INUSE 40
+
 /*
  * Shrink the slab cache on a particular node of the cache
  */
@@ -2610,6 +2612,8 @@ static unsigned long __kmem_cache_shrink
 	LIST_HEAD(zaplist);
 	int freed;
 	int inuse;
+	int nr[NR_INUSE] = { 0, };
+	int i;
 
 	spin_lock_irqsave(&n->list_lock, flags);
 	freed = sort_partial_list(s, n, scratch);
@@ -2646,6 +2650,8 @@ static unsigned long __kmem_cache_shrink
 		n->nr_partial--;
 		SetSlabFrozen(page);
 		slab_unlock(page);
+		if (inuse < NR_INUSE)
+			nr[inuse]++;
 	}
 
 	spin_unlock_irqrestore(&n->list_lock, flags);
@@ -2659,6 +2665,13 @@ static unsigned long __kmem_cache_shrink
 		if (__kmem_cache_vacate(s, page, flags, scratch) == 0)
 			freed++;
 	}
+	printk(KERN_INFO "Slab %s: Defrag freed %d pages. PartSlab config=",
+			s->name, freed << s->order);
+
+	for (i = 0; i < NR_INUSE; i++)
+		if (nr[i])
+			printk(" %d=%d", i, nr[i]);
+	printk("\n");
 	return freed;
 }