Re: 2.5.39 kmem_cache bug

[Manfred Spraul <manfred@colorfullife.com>]

Andrew Morton wrote:
> John Levon wrote:
> 
>>kmem_cache_destroy() is falsely reporting
>>"kmem_cache_destroy: Can't free all objects" in 2.5.39. I have
>>verified my code was freeing all allocated items correctly.
>>
>>Reverting this chunk :
>>
>>-                       list_add(&slabp->list, &cachep->slabs_free);
>>+/*                     list_add(&slabp->list, &cachep->slabs_free);            */
>>+                       if (unlikely(list_empty(&cachep->slabs_partial)))
>>+                               list_add(&slabp->list, &cachep->slabs_partial);
>>+                       else
>>+                               kmem_slab_destroy(cachep, slabp);
>>
>>and the problem goes away. I haven't investigated why.
>>
> 
> 
> Thanks.  That's the code which leaves one empty page available
> for new allocations rather than freeing it immediately.
> 
> It's temporary.  Ed, I think we can just do
> 
> 	if (list_empty(&cachep->slabs_free))
> 		list_add(&slabp->list, &cachep->slabs_free);
> 	else
> 		kmem_slab_destroy(cachep, slabp);
> 
> there?

Look correct.
If you apply it, then reenable the BUG check in s_show() if a slab with 
0 allocations is found on the partial list, too.

--
	Manfred