RE: [RFC PATCH v1 09/13] mm: zswap: Config variable to enable compress batching in zswap_store().

["Sridhar, Kanchana P" <kanchana.p.sridhar@intel.com>]

> -----Original Message-----
> From: Herbert Xu <herbert@gondor.apana.org.au>
> Sent: Tuesday, October 22, 2024 7:58 PM
> To: Sridhar, Kanchana P <kanchana.p.sridhar@intel.com>
> Cc: Yosry Ahmed <yosryahmed@google.com>; linux-kernel@vger.kernel.org;
> linux-mm@kvack.org; hannes@cmpxchg.org; nphamcs@gmail.com;
> chengming.zhou@linux.dev; usamaarif642@gmail.com;
> ryan.roberts@arm.com; Huang, Ying <ying.huang@intel.com>;
> 21cnbao@gmail.com; akpm@linux-foundation.org; linux-
> crypto@vger.kernel.org; davem@davemloft.net; clabbe@baylibre.com;
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> Kristen C <kristen.c.accardi@intel.com>; zanussi@kernel.org;
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> Feghali, Wajdi K <wajdi.k.feghali@intel.com>; Gopal, Vinodh
> <vinodh.gopal@intel.com>
> Subject: Re: [RFC PATCH v1 09/13] mm: zswap: Config variable to enable
> compress batching in zswap_store().
> 
> On Wed, Oct 23, 2024 at 02:17:06AM +0000, Sridhar, Kanchana P wrote:
> >
> > Thanks Yosry, for the code review comments! This is a good point. The main
> > consideration here was not to impact software compressors run on non-
> Intel
> > platforms, and only incur the memory footprint cost of multiple
> > acomp_req/buffers in "struct crypto_acomp_ctx" if there is IAA to reduce
> > latency with parallel compressions.
> 
> I'm working on a batching mechanism for crypto_ahash interface,
> where the requests are simply chained together and then submitted.
> 
> The same mechanism should work for crypto_acomp as well:
> 
> +       for (i = 0; i < num_mb; ++i) {
> +               if (testmgr_alloc_buf(data[i].xbuf))
> +                       goto out;
> +
> +               crypto_init_wait(&data[i].wait);
> +
> +               data[i].req = ahash_request_alloc(tfm, GFP_KERNEL);
> +               if (!data[i].req) {
> +                       pr_err("alg: hash: Failed to allocate request for %s\n",
> +                              algo);
> +                       goto out;
> +               }
> +
> +               if (i)
> +                       ahash_request_chain(data[i].req, data[0].req);
> +               else
> +                       ahash_reqchain_init(data[i].req, 0, crypto_req_done,
> +                                           &data[i].wait);
> +
> +               sg_init_table(data[i].sg, XBUFSIZE);
> +               for (j = 0; j < XBUFSIZE; j++) {
> +                       sg_set_buf(data[i].sg + j, data[i].xbuf[j], PAGE_SIZE);
> +                       memset(data[i].xbuf[j], 0xff, PAGE_SIZE);
> +               }
> +       }

Thanks Herbert, for letting us know! Sure, we will look forward to these
changes when they are ready, to look into incorporating in the iaa_crypto
driver.

Thanks,
Kanchana

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