From: Yosry Ahmed <yosry.ahmed@linux.dev>
To: Herbert Xu <herbert@gondor.apana.org.au>, Barry Song <21cnbao@gmail.com>
Cc: "Sridhar, Kanchana P" <kanchana.p.sridhar@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"hannes@cmpxchg.org" <hannes@cmpxchg.org>,
"nphamcs@gmail.com" <nphamcs@gmail.com>,
"chengming.zhou@linux.dev" <chengming.zhou@linux.dev>,
"usamaarif642@gmail.com" <usamaarif642@gmail.com>,
"ryan.roberts@arm.com" <ryan.roberts@arm.com>,
"21cnbao@gmail.com" <21cnbao@gmail.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
"davem@davemloft.net" <davem@davemloft.net>,
"clabbe@baylibre.com" <clabbe@baylibre.com>,
"ardb@kernel.org" <ardb@kernel.org>,
"ebiggers@google.com" <ebiggers@google.com>,
"surenb@google.com" <surenb@google.com>,
"Accardi, Kristen C" <kristen.c.accardi@intel.com>,
"Feghali, Wajdi K" <wajdi.k.feghali@intel.com>,
"Gopal, Vinodh" <vinodh.gopal@intel.com>
Subject: Re: [PATCH v5 02/12] crypto: acomp - Define new interfaces for compress/decompress batching.
Date: Thu, 20 Feb 2025 17:32:46 +0000 [thread overview]
Message-ID: <Z7dnPh4tPxLO1UEo@google.com> (raw)
In-Reply-To: <Z7F1B_blIbByYBzz@gondor.apana.org.au>
On Sun, Feb 16, 2025 at 01:17:59PM +0800, Herbert Xu wrote:
> On Mon, Jan 06, 2025 at 07:10:53PM -0800, Yosry Ahmed wrote:
> >
> > The main problem is memory usage. Zswap needs a PAGE_SIZE*2-sized
> > buffer for each request on each CPU. We preallocate these buffers to
> > avoid trying to allocate this much memory in the reclaim path (i.e.
> > potentially allocating two pages to reclaim one).
>
> Actually this PAGE_SIZE * 2 thing baffles me. Why would you
> allocate more memory than the input? The comment says that it's
> because certain hardware accelerators will disregard the output
> buffer length, but surely that's just a bug in the driver?
>
> Which driver does this? We should fix it or remove it if it's
> writing output with no regard to the maximum length.
>
> You should only ever need PAGE_SIZE for the output buffer, if
> the output exceeds that then just fail the compression.
I agree this should be fixed if it can be. This was discussed before
here:
https://lore.kernel.org/lkml/CAGsJ_4wuTZcGurby9h4PU2DwFaiEKB4bxuycaeyz3bPw3jSX3A@mail.gmail.com/
Barry is the one who brought up why we need PAGE_SIZE*2. Barry, could
you please chime in here?
>
> Cheers,
> --
> Email: Herbert Xu <herbert@gondor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
>
next prev parent reply other threads:[~2025-02-20 17:32 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-21 6:31 [PATCH v5 00/12] zswap IAA compress batching Kanchana P Sridhar
2024-12-21 6:31 ` [PATCH v5 01/12] crypto: acomp - Add synchronous/asynchronous acomp request chaining Kanchana P Sridhar
2024-12-21 6:31 ` [PATCH v5 02/12] crypto: acomp - Define new interfaces for compress/decompress batching Kanchana P Sridhar
2024-12-28 11:46 ` Herbert Xu
2025-01-06 17:37 ` Sridhar, Kanchana P
2025-01-06 23:24 ` Yosry Ahmed
2025-01-07 1:36 ` Sridhar, Kanchana P
2025-01-07 1:46 ` Yosry Ahmed
2025-01-07 2:06 ` Herbert Xu
2025-01-07 3:10 ` Yosry Ahmed
2025-01-08 1:38 ` Herbert Xu
2025-01-08 1:43 ` Yosry Ahmed
2025-02-16 5:17 ` Herbert Xu
2025-02-20 17:32 ` Yosry Ahmed [this message]
2025-02-22 6:26 ` Barry Song
2025-02-22 6:34 ` Herbert Xu
2025-02-22 6:41 ` Barry Song
2025-02-22 6:52 ` Herbert Xu
2025-02-22 7:13 ` Barry Song
2025-02-22 7:22 ` Herbert Xu
2025-02-22 8:21 ` Barry Song
2025-02-24 21:49 ` Yosry Ahmed
2025-02-27 3:05 ` Barry Song
2025-02-22 12:31 ` Sergey Senozhatsky
2025-02-22 14:27 ` Sergey Senozhatsky
2025-02-23 0:14 ` Herbert Xu
2025-02-23 2:09 ` Sergey Senozhatsky
2025-02-23 2:52 ` Herbert Xu
2025-02-23 3:12 ` Sergey Senozhatsky
2025-02-23 3:38 ` Herbert Xu
2025-02-23 4:02 ` Sergey Senozhatsky
2025-02-23 6:04 ` Herbert Xu
2025-02-22 16:24 ` Barry Song
2025-02-23 0:24 ` Herbert Xu
2025-02-23 1:57 ` Sergey Senozhatsky
2025-01-07 2:04 ` Herbert Xu
2024-12-21 6:31 ` [PATCH v5 03/12] crypto: iaa - Add an acomp_req flag CRYPTO_ACOMP_REQ_POLL to enable async mode Kanchana P Sridhar
2024-12-21 6:31 ` [PATCH v5 04/12] crypto: iaa - Implement batch_compress(), batch_decompress() API in iaa_crypto Kanchana P Sridhar
2024-12-22 4:07 ` kernel test robot
2024-12-21 6:31 ` [PATCH v5 05/12] crypto: iaa - Make async mode the default Kanchana P Sridhar
2024-12-21 6:31 ` [PATCH v5 06/12] crypto: iaa - Disable iaa_verify_compress by default Kanchana P Sridhar
2024-12-21 6:31 ` [PATCH v5 07/12] crypto: iaa - Re-organize the iaa_crypto driver code Kanchana P Sridhar
2024-12-21 6:31 ` [PATCH v5 08/12] crypto: iaa - Map IAA devices/wqs to cores based on packages instead of NUMA Kanchana P Sridhar
2024-12-21 6:31 ` [PATCH v5 09/12] crypto: iaa - Distribute compress jobs from all cores to all IAAs on a package Kanchana P Sridhar
2024-12-21 6:31 ` [PATCH v5 10/12] mm: zswap: Allocate pool batching resources if the crypto_alg supports batching Kanchana P Sridhar
2025-01-07 0:58 ` Yosry Ahmed
2025-01-08 3:26 ` Sridhar, Kanchana P
2025-01-08 4:16 ` Yosry Ahmed
2024-12-21 6:31 ` [PATCH v5 11/12] mm: zswap: Restructure & simplify zswap_store() to make it amenable for batching Kanchana P Sridhar
2025-01-07 1:16 ` Yosry Ahmed
2025-01-08 3:57 ` Sridhar, Kanchana P
2025-01-08 4:22 ` Yosry Ahmed
2024-12-21 6:31 ` [PATCH v5 12/12] mm: zswap: Compress batching with Intel IAA in zswap_store() of large folios Kanchana P Sridhar
2025-01-07 1:19 ` Yosry Ahmed
2025-01-07 1:44 ` [PATCH v5 00/12] zswap IAA compress batching Yosry Ahmed
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