RE: [PATCH v3 12/13] mm: Add sysctl vm.compress-batching switch for compress batching during swapout.

Sridhar, Kanchana P
2024-11-07T22:25:07Z

> -----Original Message-----
> From: Johannes Weiner <hannes@cmpxchg.org>
> Sent: Thursday, November 7, 2024 9:34 AM
> To: Sridhar, Kanchana P <kanchana.p.sridhar@intel.com>
> Cc: linux-kernel@vger.kernel.org; linux-mm@kvack.org;
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> Subject: Re: [PATCH v3 12/13] mm: Add sysctl vm.compress-batching switch
> for compress batching during swapout.
>
> On Wed, Nov 06, 2024 at 11:21:04AM -0800, Kanchana P Sridhar wrote:
> > The sysctl vm.compress-batching parameter is 0 by default. If the platform
> > has Intel IAA, the user can run experiments with IAA compress batching of
> > large folios in zswap_store() as follows:
> >
> > sysctl vm.compress-batching=1
> > echo deflate-iaa > /sys/module/zswap/parameters/compressor
>
> A sysctl seems uncalled for. Can't the batching code be gated on
> deflate-iaa being the compressor? It can still be generalized later if
> another compressor is shown to benefit from batching.

That's a very valid point. I will gate the batching code based on the
availability of the crypto batch_compress() and batch_decompress()
interfaces in the compressor. I agree, this can still be generalized later to
other compressors, potentially via these same batching API.

Thanks,
Kanchana