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Date:   Mon, 4 Oct 2021 13:39:46 +0200
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Subject: Re: [QUESTION] is SLAB considered legacy and deprecated?
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To:     Hyeonggon Yoo <42.hyeyoo@gmail.com>,
        David Rientjes <rientjes@google.com>
Cc:     linux-mm@kvack.org, Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org
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From:   Vlastimil Babka <vbabka@suse.cz>
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On 10/4/21 08:01, Hyeonggon Yoo wrote:
> On Sun, Oct 03, 2021 at 06:25:29PM -0700, David Rientjes wrote:
>> I would disagree that SLAB isn't currently maintained, I think it's 
>> actively maintained.
> 
> I thought it was not actively maintained because most of patches were
> fixups and cleanups for years and as Vlastimil said, new features are

Fixups and cleanups still count as "actively maintained". The opposite
case would be "nobody uses it because it was broken for years since
commit X and we only noticed now".

> only added to SLUB. development was focused on SLUB.
> 
>> I think the general guidance is that changes for both allocators can still
>> be merged upstream if they show a significant win (improved performnace, 
>> maintaining performance while reducing memory footprint, code hygiene, 
>> etc) and there's no specific policy that we cannot make changes to 
>> mm/slab.c.
> 
> Good.
> 
> I see things to improve in SLAB and want to improve it.
> I will appreciate if you review them.

It would be great if your motivation started with "I prefer SLAB over
SLUB because X and Y but I need to improve Z", not just a theoretical
concern.

> Thanks,
> Hyeonggon
>