From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D702C433FF for ; Mon, 29 Jul 2019 21:25:44 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id F2CEB206DD for ; Mon, 29 Jul 2019 21:25:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F2CEB206DD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:56502 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hsD9L-0004CZ-7P for qemu-devel@archiver.kernel.org; Mon, 29 Jul 2019 17:25:43 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58190) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hsD8U-0003bK-IJ for qemu-devel@nongnu.org; Mon, 29 Jul 2019 17:24:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hsD8T-00014Z-Ly for qemu-devel@nongnu.org; Mon, 29 Jul 2019 17:24:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39866) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hsD8R-00012y-EH; Mon, 29 Jul 2019 17:24:47 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A356A30842A9; Mon, 29 Jul 2019 21:24:46 +0000 (UTC) Received: from [10.3.116.93] (ovpn-116-93.phx2.redhat.com [10.3.116.93]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6E47B5C1A1; Mon, 29 Jul 2019 21:24:40 +0000 (UTC) To: Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, qemu-block@nongnu.org References: <20190725100550.33801-1-vsementsov@virtuozzo.com> <20190725100550.33801-4-vsementsov@virtuozzo.com> From: Eric Blake Openpgp: preference=signencrypt Autocrypt: addr=eblake@redhat.com; keydata= xsBNBEvHyWwBCACw7DwsQIh0kAbUXyqhfiKAKOTVu6OiMGffw2w90Ggrp4bdVKmCaEXlrVLU xphBM8mb+wsFkU+pq9YR621WXo9REYVIl0FxKeQo9dyQBZ/XvmUMka4NOmHtFg74nvkpJFCD TUNzmqfcjdKhfFV0d7P/ixKQeZr2WP1xMcjmAQY5YvQ2lUoHP43m8TtpB1LkjyYBCodd+LkV GmCx2Bop1LSblbvbrOm2bKpZdBPjncRNob73eTpIXEutvEaHH72LzpzksfcKM+M18cyRH+nP sAd98xIbVjm3Jm4k4d5oQyE2HwOur+trk2EcxTgdp17QapuWPwMfhaNq3runaX7x34zhABEB AAHNHkVyaWMgQmxha2UgPGVibGFrZUByZWRoYXQuY29tPsLAegQTAQgAJAIbAwULCQgHAwUV CgkICwUWAgMBAAIeAQIXgAUCS8fL9QIZAQAKCRCnoWtKJSdDahBHCACbl/5FGkUqJ89GAjeX RjpAeJtdKhujir0iS4CMSIng7fCiGZ0fNJCpL5RpViSo03Q7l37ss+No+dJI8KtAp6ID+PMz wTJe5Egtv/KGUKSDvOLYJ9WIIbftEObekP+GBpWP2+KbpADsc7EsNd70sYxExD3liwVJYqLc Rw7so1PEIFp+Ni9A1DrBR5NaJBnno2PHzHPTS9nmZVYm/4I32qkLXOcdX0XElO8VPDoVobG6 gELf4v/vIImdmxLh/w5WctUpBhWWIfQDvSOW2VZDOihm7pzhQodr3QP/GDLfpK6wI7exeu3P pfPtqwa06s1pae3ad13mZGzkBdNKs1HEm8x6zsBNBEvHyWwBCADGkMFzFjmmyqAEn5D+Mt4P zPdO8NatsDw8Qit3Rmzu+kUygxyYbz52ZO40WUu7EgQ5kDTOeRPnTOd7awWDQcl1gGBXgrkR pAlQ0l0ReO57Q0eglFydLMi5bkwYhfY+TwDPMh3aOP5qBXkm4qIYSsxb8A+i00P72AqFb9Q7 3weG/flxSPApLYQE5qWGSXjOkXJv42NGS6o6gd4RmD6Ap5e8ACo1lSMPfTpGzXlt4aRkBfvb NCfNsQikLZzFYDLbQgKBA33BDeV6vNJ9Cj0SgEGOkYyed4I6AbU0kIy1hHAm1r6+sAnEdIKj cHi3xWH/UPrZW5flM8Kqo14OTDkI9EtlABEBAAHCwF8EGAEIAAkFAkvHyWwCGwwACgkQp6Fr SiUnQ2q03wgAmRFGDeXzc58NX0NrDijUu0zx3Lns/qZ9VrkSWbNZBFjpWKaeL1fdVeE4TDGm I5mRRIsStjQzc2R9b+2VBUhlAqY1nAiBDv0Qnt+9cLiuEICeUwlyl42YdwpmY0ELcy5+u6wz mK/jxrYOpzXKDwLq5k4X+hmGuSNWWAN3gHiJqmJZPkhFPUIozZUCeEc76pS/IUN72NfprZmF Dp6/QDjDFtfS39bHSWXKVZUbqaMPqlj/z6Ugk027/3GUjHHr8WkeL1ezWepYDY7WSoXwfoAL 2UXYsMAr/uUncSKlfjvArhsej0S4zbqim2ZY6S8aRWw94J3bSvJR+Nwbs34GPTD4Pg== Organization: Red Hat, Inc. Message-ID: Date: Mon, 29 Jul 2019 16:24:39 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20190725100550.33801-4-vsementsov@virtuozzo.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="JvnGETKiE3y0Bb1A2GKC0lFYaxtOSIYX6" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Mon, 29 Jul 2019 21:24:46 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v3 3/3] nbd: improve CMD_CACHE: use BDRV_REQ_PREFETCH X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, fam@euphon.net, mreitz@redhat.com, stefanha@redhat.com, den@openvz.org, jsnow@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --JvnGETKiE3y0Bb1A2GKC0lFYaxtOSIYX6 Content-Type: multipart/mixed; boundary="7DXtuCtQCPjHrlVVZ3XA9aAHv2BaqsOch"; protected-headers="v1" From: Eric Blake To: Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, qemu-block@nongnu.org Cc: jsnow@redhat.com, mreitz@redhat.com, kwolf@redhat.com, fam@euphon.net, stefanha@redhat.com, den@openvz.org Message-ID: Subject: Re: [PATCH v3 3/3] nbd: improve CMD_CACHE: use BDRV_REQ_PREFETCH References: <20190725100550.33801-1-vsementsov@virtuozzo.com> <20190725100550.33801-4-vsementsov@virtuozzo.com> In-Reply-To: <20190725100550.33801-4-vsementsov@virtuozzo.com> --7DXtuCtQCPjHrlVVZ3XA9aAHv2BaqsOch Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 7/25/19 5:05 AM, Vladimir Sementsov-Ogievskiy wrote: > This helps to avoid extra io, allocations and memory copying. > We assume here that CMD_CACHE is always used with copy-on-read, as > otherwise it's a noop. >=20 > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > nbd/server.c | 43 +++++++++++++++++++++++++++++++++++-------- > 1 file changed, 35 insertions(+), 8 deletions(-) libnbd is able to test NBD_CMD_CACHE requests, and I've confirmed that behavior looks sane under requests issued that way. I'm wondering if qemu-io should also be able to drive this mode of operation, so that we can give it iotest coverage without depending on libnbd. Reviewed-by: Eric Blake --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org --7DXtuCtQCPjHrlVVZ3XA9aAHv2BaqsOch-- --JvnGETKiE3y0Bb1A2GKC0lFYaxtOSIYX6 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEccLMIrHEYCkn0vOqp6FrSiUnQ2oFAl0/ZBcACgkQp6FrSiUn Q2piqwf9GkW1J2wWRfanofOBM2Gfd59lxQT0NysiXy1EAXHDqV6d44KsNxUAh0+k G7waRCrpiHWaNL1ctPCcUiBv92yWDdLJ0wNplLn0SfljKPu4uhYfmSEVGnuw8SSi qBXp+/1f4yEenDkeFIJqFDOOc9G3Ue2RBoXXm4IhLdvDOb+ufqD8U/a5ttffh/ZM 2GN8n3wDiG5ma9yAwZa2InQLoowIwz+cS/GNxCSXbySfKNySIWffMWOdqx24Zlwf MlC4dAxZpdW3f8X+A780/jOJSPQcN45kiyeJlgJEFxgZxGFho0O0WNXgL+4YBXqK WS/fYr8BDAS6aNWKhOlcBzF0r5RDjA== =yZZX -----END PGP SIGNATURE----- --JvnGETKiE3y0Bb1A2GKC0lFYaxtOSIYX6--