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=-4.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 9AF55C433E1 for ; Wed, 22 Jul 2020 07:15:26 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 56AEC2065F for ; Wed, 22 Jul 2020 07:15:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=wdc.com header.i=@wdc.com header.b="PCYKbK9X"; dkim=pass (1024-bit key) header.d=sharedspace.onmicrosoft.com header.i=@sharedspace.onmicrosoft.com header.b="fb6snm4D" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 56AEC2065F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=wdc.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CA0786B0003; Wed, 22 Jul 2020 03:15:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C27C66B0005; Wed, 22 Jul 2020 03:15:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AA11B6B0006; Wed, 22 Jul 2020 03:15:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0203.hostedemail.com [216.40.44.203]) by kanga.kvack.org (Postfix) with ESMTP id 8FF7F6B0003 for ; Wed, 22 Jul 2020 03:15:25 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 4F5CC181CBC28 for ; Wed, 22 Jul 2020 07:15:25 +0000 (UTC) X-FDA: 77064851010.17.paper80_551568826f34 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin17.hostedemail.com (Postfix) with ESMTP id 567ED1848A034 for ; Wed, 22 Jul 2020 07:14:17 +0000 (UTC) X-HE-Tag: paper80_551568826f34 X-Filterd-Recvd-Size: 8247 Received: from esa5.hgst.iphmx.com (esa5.hgst.iphmx.com [216.71.153.144]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Wed, 22 Jul 2020 07:14:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1595402056; x=1626938056; h=from:to:cc:subject:date:message-id:references: content-transfer-encoding:mime-version; bh=eDgXJDrRcHBdx/h+ukaTHEZJ1bIcCGUbvV+Qo/Lb7u8=; b=PCYKbK9X8hhUnFfbj/S6JpLPRWk8aklt7fyj7mrtccb9sJz22Nnof9qp U2UV9B0mgphlItdmTZnKYmYiDetEoUGTDHeQKy0jmwiL6wdFIX9nXoQbn ddpUL8wmpnKpEEojbYqrRuMUlW1MJgw1s8WFkCDp1K9A7bcLFyJSTkhzz dv+SPtXdOA4TTSFbVN+Si0QpId9ZGhtt429o+QVE5CNnYfJJZjQ3TYJu5 0WZXQUA3FEJYvA12nkrY8G6vck0J1yna405R/vK/Xdak0KF85dPEfjvvF YcpZPq3z3VpG0ysVfNh/X+FXbwSzs60i+6r2hVksu+eCp58iSQHCruE3F A==; IronPort-SDR: wHJ0sUf5fKcvjCD5KELUHIpZWn534zNWdK/RdtaRiz1HpW9fNPYLc4k8C4dqSOcfwS/VkCC3rx Sk/DCgaT2zjtuKphqdg/47ePdrawLXPmVN2QMtMo7E0n8aRVX39Q9GoXFOciL0NnbEnGthc+oL wKE8O+fmKJh/ArDe+3CyV970ETjHHfpr7HhppoSlYWcT+6B4L74A6J91BUPCZjsV+IQa9ZmuOt HXgR1QxLxdU3LtzIxWgZq9O38VJ9mu1kIuMuQbPMcgkwutxKcStu83NVlPH/mucXJPrT+HCdyA TL8= X-IronPort-AV: E=Sophos;i="5.75,381,1589212800"; d="scan'208";a="143183356" Received: from mail-mw2nam10lp2102.outbound.protection.outlook.com (HELO NAM10-MW2-obe.outbound.protection.outlook.com) ([104.47.55.102]) by ob1.hgst.iphmx.com with ESMTP; 22 Jul 2020 15:13:57 +0800 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=nHoUfvDb/kH0zR6mxIRvNX8FNQPu9uGYgHKnoRdnMOBY6xGiervqOLb7pqlqs4sOYAm0IAKucRJKiYCKF+AtNJoTEa+LBec/WeO0IHg4etpuih579978R6SPb+WzU19Oo+HpBE6wPz9ObYIpLXyE8ju1V2Wh56IqI3kgqXsvMHc2/P0GfSbfLUaBQhMuAe/LF6iqwGFIh4f3e9NYmNGFqDMOk3hTyzvCzeI6dbRHF9E1qGEbdTJuLzjkURe1Q1WrMSH14rPq5iToCspKc0X6jIhgjgjxVm0pFX+Um4nqw52iiyruKz2BcUR91fjfcFkRPEAMoU0icnG9rliPsaTTig== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=poiwM82pTnOPiJnHxVcFkqqb2XVkaMdwQOlgju+7S0g=; b=et0WO/inY40469u+0eXd6/sKGwXMBWQjpBcH1bRYyYdAAjqsnFAvc5J9zAkvv2eFurie54/v3jeg9gglA1T4E2B3bRVRyccL/TNCGHRiJOFqzSHDd6JSHTZdGO1tgKBHOjAeNXVJ+xuxwN0rlMWryGDg/s4+ocByHOeMBEtNPbmTjU5d/Bb1IYXwpsjxNPZAF6L20VIApca8PBc6xi3YT8Kt7PQGaa0KPJy6TAKcKR50VIU6hb83IHuG/Rsighle0oaYAz7h9YmJfGWgQXN5x1ulJbTqXXRD02EEylTR3UEYpEN3z9YlE/k1CVhbtS9jvzEYyAFLmArfT7elvt3+iQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=wdc.com; dmarc=pass action=none header.from=wdc.com; dkim=pass header.d=wdc.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sharedspace.onmicrosoft.com; s=selector2-sharedspace-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=poiwM82pTnOPiJnHxVcFkqqb2XVkaMdwQOlgju+7S0g=; b=fb6snm4DA8NLZm2oGpMp7J/pm7U2fsnXO6PhYWFCFyVRMrh4KmYwDa9mImLx30Ku8pISeP92XEpKj9pvTA/e5uWUSC75GEKjgviQcA7HLvtTafGxQYc/BTaJeuseq+lE0ne5eq4E+N03ryf9wqb6RSyAR98yw+Q4IWKCPCKmNuY= Received: from SN4PR0401MB3598.namprd04.prod.outlook.com (2603:10b6:803:47::21) by SN6PR04MB4862.namprd04.prod.outlook.com (2603:10b6:805:90::27) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3195.24; Wed, 22 Jul 2020 07:13:55 +0000 Received: from SN4PR0401MB3598.namprd04.prod.outlook.com ([fe80::1447:186c:326e:30b2]) by SN4PR0401MB3598.namprd04.prod.outlook.com ([fe80::1447:186c:326e:30b2%7]) with mapi id 15.20.3195.026; Wed, 22 Jul 2020 07:13:55 +0000 From: Johannes Thumshirn To: Christoph Hellwig , Jens Axboe CC: Song Liu , Hans de Goede , Richard Weinberger , Minchan Kim , "linux-mtd@lists.infradead.org" , "dm-devel@redhat.com" , "linux-block@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "drbd-dev@lists.linbit.com" , "linux-raid@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "cgroups@vger.kernel.org" Subject: Re: [PATCH 06/14] block: lift setting the readahead size into the block layer Thread-Topic: [PATCH 06/14] block: lift setting the readahead size into the block layer Thread-Index: AQHWX/E8oA9T0pQ4oE+KEOpJvS2fxw== Date: Wed, 22 Jul 2020 07:13:54 +0000 Message-ID: References: <20200722062552.212200-1-hch@lst.de> <20200722062552.212200-7-hch@lst.de> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: lst.de; dkim=none (message not signed) header.d=none;lst.de; dmarc=none action=none header.from=wdc.com; x-originating-ip: [129.253.240.72] x-ms-publictraffictype: Email x-ms-office365-filtering-ht: Tenant x-ms-office365-filtering-correlation-id: d8ce3f04-9052-4911-3702-08d82e0ecb78 x-ms-traffictypediagnostic: SN6PR04MB4862: x-microsoft-antispam-prvs: wdcipoutbound: EOP-TRUE x-ms-oob-tlc-oobclassifiers: OLM:8273; x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: oImQpW7CKR7N7nwIN1ti/wtbBp/l+aSnH3vWZaECMFtX24P/1CMnzbX29If187tW5gzPOp/Abd9iDRIChfVwCh0ocv3+uQnJ/vgQxvyw4DtEr5Ri8DnHfK21NP/3blMOzvye4EnCY1CI86qK3DwYS24zAffmZ/Zb4d5H83UZqKo7CNUzdPXa6cGsXGeH3nYtgrG3mMbbeD+wZDGBx6eHnIwTyKovexz8a+Nw+UHRh/EeeXs8IkfTGH1iBTTfhyleJni37gTbf4HHSYtqRyLlmr8N11xP2cG+oij6V4aHXQpr+fGkjiCcwy7EUvOQj/FX x-forefront-antispam-report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SN4PR0401MB3598.namprd04.prod.outlook.com;PTR:;CAT:NONE;SFTY:;SFS:(4636009)(136003)(39860400002)(376002)(366004)(346002)(396003)(4744005)(5660300002)(86362001)(54906003)(110136005)(55016002)(316002)(52536014)(7416002)(8936002)(76116006)(91956017)(66476007)(6506007)(66556008)(8676002)(33656002)(64756008)(66446008)(71200400001)(53546011)(478600001)(26005)(7696005)(66946007)(4326008)(186003)(2906002)(9686003);DIR:OUT;SFP:1102; x-ms-exchange-antispam-messagedata: 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 x-ms-exchange-transport-forked: True Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: wdc.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: SN4PR0401MB3598.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: d8ce3f04-9052-4911-3702-08d82e0ecb78 X-MS-Exchange-CrossTenant-originalarrivaltime: 22 Jul 2020 07:13:54.9928 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b61c8803-16f3-4c35-9b17-6f65f441df86 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: wocQapUT1WYCqJh62OVuMi6iUe/l+yc5vIOJHS23u+JQnUgO7kjh9b2aj7QsttihnkJ8Otno8w8Ezb9/1OKaCEZwclMpba2Nbu1PcZUT0dk= X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN6PR04MB4862 X-Rspamd-Queue-Id: 567ED1848A034 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 22/07/2020 08:27, Christoph Hellwig wrote:=0A= > + q->backing_dev_info->ra_pages =3D=0A= > + max(queue_io_opt(q) * 2 / PAGE_SIZE, VM_READAHEAD_PAGES);=0A= =0A= Dumb question, wouldn't a '>> PAGE_SHIFT' be better instead of a potentiall= y =0A= costly division?=0A= =0A= Or aren't we caring at all as it's a) not in the fast-path and b) compilers= =0A= can optimize it to a shift?=0A=