RE: [PATCH v12 23/23] mm: zswap: Batched zswap_compress() with compress batching of large folios.

[Sridhar, Kanchana P]

> -----Original Message-----
> From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Sent: Tuesday, October 21, 2025 10:18 PM
> To: Sridhar, Kanchana P <kanchana.p.sridhar@xxxxxxxxx>
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> Subject: Re: [PATCH v12 23/23] mm: zswap: Batched zswap_compress() with
> compress batching of large folios.
> 
> On Thu, Sep 25, 2025 at 08:35:02PM -0700, Kanchana P Sridhar wrote:
> >
> > Another initialization level optimization that happens in
> > zswap_cpu_comp_prepare() is, only for batching compressors, we allocate
> > extra memory for "batch-size" int pointers in the
> > @acomp_ctx->req->__ctx[] that are statically set to track the output SG
> > lists' lengths. This optimization was necessary to avoid the latency
> 
> There is no need for this allocation.  Just store the output lengths
> in each destination scatterlist entry.

Thanks Herbert, for this suggestion. I have included this in the v13 code
that I am currently validating and expect to post an updated patch-set
within a couple of days.

> 
> Before the call to acomp, the destination SG list should contain as
> many elements as the number of units.  On return, the dst lengths
> should be stored in each destination SG entry.

Yes, confirming that this is the case.

Best regards,
Kanchana

> 
> Cheers,
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> Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
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