On 05/18/2012 08:19 PM, Christoph Lameter wrote:

-/*
- * Close a cache and release the kmem_cache structure
- * (must be used for caches created using kmem_cache_create)
- */
-void kmem_cache_destroy(struct kmem_cache *s)
+int __kmem_cache_shutdown(struct kmem_cache *s)
  {
-	mutex_lock(&slab_mutex);
-	s->refcount--;
-	if (!s->refcount) {
-		list_del(&s->list);
-		mutex_unlock(&slab_mutex);
-		if (kmem_cache_close(s)) {
-			printk(KERN_ERR "SLUB %s: %s called for cache that "
-				"still has objects.\n", s->name, __func__);
-			dump_stack();
-		}
-		if (s->flags&  SLAB_DESTROY_BY_RCU)
-			rcu_barrier();
-		sysfs_slab_remove(s);
-	} else
-		mutex_unlock(&slab_mutex);
+	return kmem_cache_close(s);
+}

Something doesn't smell right here. It seems that we're now closing the 
caches right away. That wasn't the case before, nor it should be: For 
aliases, we should only decrease the refcount.

So unless I am missing something, it seems to me the correct code would be:

s->refcount--;
if (!s->refcount)
     return kmem_cache_close;
return 0;

And while we're on that, that makes the sequence list_del() -> if it 
fails -> list_add() in the common kmem_cache_destroy a bit clumsy. 
Aliases will be re-added to the list quite frequently. Not that it is a 
big problem, but still...

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