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Subject: Re: [PATCH 3/3] dcache: account external names as indirectly
 reclaimable memory
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From: Vlastimil Babka <vbabka@suse.cz>
Message-ID: <a6413098-b37c-a6b8-45cb-ce273ff16c29@suse.cz>
Date: Mon, 16 Apr 2018 21:57:50 +0200
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To: Michal Hocko <mhocko@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>, Minchan Kim <minchan@kernel.org>, Roman Gushchin <guro@fb.com>, linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>, Alexander Viro <viro@zeniv.linux.org.uk>, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, lsf-pc@lists.linux-foundation.org

On 04/16/2018 02:27 PM, Michal Hocko wrote:
> On Mon 16-04-18 14:06:21, Vlastimil Babka wrote:
>>
>> For example the percpu (and other) array caches...
>>
>>> maybe it will turn out that such a large
>>> portion of the chache would need to duplicate the state that a
>>> completely new cache would be more reasonable.
>>
>> I'm afraid that's the case, yes.
>>
>>> Is this worth exploring
>>> at least? I mean something like this should help with the fragmentation
>>> already AFAIU. Accounting would be just free on top.
>>
>> Yep. It could be also CONFIG_urable so smaller systems don't need to
>> deal with the memory overhead of this.
>>
>> So do we put it on LSF/MM agenda?
> 
> If you volunteer to lead the discussion, then I do not have any
> objections.

Sure, let's add the topic of SLAB_MINIMIZE_WASTE [1] as well.

Something like "Supporting reclaimable kmalloc caches and large
non-buddy-sized objects in slab allocators" ?

[1] https://marc.info/?l=linux-mm&m=152156671614796&w=2