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Date: Fri, 20 Jul 2012 19:16:56 -0300
From: Glauber Costa <glommer@parallels.com>
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To: Christoph Lameter <cl@linux.com>
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Subject: Re: [PATCH v4 24/25] memcg/slub: shrink dead caches
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On 07/06/2012 12:16 PM, Christoph Lameter wrote:
> On Mon, 18 Jun 2012, Glauber Costa wrote:
> 
>> In the slub allocator, when the last object of a page goes away, we
>> don't necessarily free it - there is not necessarily a test for empty
>> page in any slab_free path.
> 
> This is the same btw in SLAB which keeps objects in per cpu caches and
> keeps empty slab pages on special queues.
> 
>> This patch marks all memcg caches as dead. kmem_cache_shrink is called
>> for the ones who are not yet dead - this will force internal cache
>> reorganization, and then all references to empty pages will be removed.
> 
> You need to call this also for slab to drain the caches and free the pages
> on the empty list.
> 
Doesn't the SLAB have a time-based reaper for that?

That's why I was less concerned with the SLAB, but I can certainly call
it for both.