linux-kernel - Re: [PATCH v13 22/22] mm: zswap: Batched zswap_compress() with compress batching of large folios.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aTZExW2LgFNTfwVJ@gondor.apana.org.au>
Date: Mon, 8 Dec 2025 11:23:49 +0800
From: Herbert Xu <herbert@...dor.apana.org.au>
To: "Sridhar, Kanchana P" <kanchana.p.sridhar@...el.com>
Cc: Yosry Ahmed <yosry.ahmed@...ux.dev>, SeongJae Park <sj@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	"hannes@...xchg.org" <hannes@...xchg.org>,
	"nphamcs@...il.com" <nphamcs@...il.com>,
	"chengming.zhou@...ux.dev" <chengming.zhou@...ux.dev>,
	"usamaarif642@...il.com" <usamaarif642@...il.com>,
	"ryan.roberts@....com" <ryan.roberts@....com>,
	"21cnbao@...il.com" <21cnbao@...il.com>,
	"ying.huang@...ux.alibaba.com" <ying.huang@...ux.alibaba.com>,
	"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
	"senozhatsky@...omium.org" <senozhatsky@...omium.org>,
	"kasong@...cent.com" <kasong@...cent.com>,
	"linux-crypto@...r.kernel.org" <linux-crypto@...r.kernel.org>,
	"davem@...emloft.net" <davem@...emloft.net>,
	"clabbe@...libre.com" <clabbe@...libre.com>,
	"ardb@...nel.org" <ardb@...nel.org>,
	"ebiggers@...gle.com" <ebiggers@...gle.com>,
	"surenb@...gle.com" <surenb@...gle.com>,
	"Accardi, Kristen C" <kristen.c.accardi@...el.com>,
	"Gomes, Vinicius" <vinicius.gomes@...el.com>,
	"Feghali, Wajdi K" <wajdi.k.feghali@...el.com>,
	"Gopal, Vinodh" <vinodh.gopal@...el.com>
Subject: Re: [PATCH v13 22/22] mm: zswap: Batched zswap_compress() with
 compress batching of large folios.

On Wed, Nov 26, 2025 at 08:05:40PM +0000, Sridhar, Kanchana P wrote:
>
> Herbert, to make sure I understand, will you be implementing all of these
> features in crypto_acomp for software compressors? I would appreciate it
> if you can clarify:
> 
> 1) Error & compressed length propagation to the dst sg->length only for
>     non-batching compressors.
>     a) For batching compressors, this wouldn't apply since errors could occur
>         for any page in the batch, and the first page (dst sg->length) could have
>         successfully compressed.

This would be the first step.

> 2) Will you also be handling the case where zswap can send an SG list batch
>      with multiple pages to a non-batching compressor, and the crypto_acomp
>      API will internally compress each page sequentially, propagate
>      errors/compress lengths before returning?
>         
> If so, this would really standardize the code in zswap for batching and
> non-batching compressors.

Yes this will be done as the next step.  My understanding is that
your patch-set doesn't require this yet as all non-batching compressors
will have a batch size of 1.

But yes this certainly will be extended, not just with sequential
processing, but we could also use pcrypt/cryptd to parallelise the
compression across CPUs.

Cheers,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt