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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 259CBC33CB2 for ; Fri, 31 Jan 2020 03:27:18 +0000 (UTC) Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (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 A21632082E for ; Fri, 31 Jan 2020 03:27:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A21632082E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=vt.edu Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernelnewbies-bounces@kernelnewbies.org Received: from localhost ([::1] helo=shelob.surriel.com) by shelob.surriel.com with esmtp (Exim 4.92.3) (envelope-from ) id 1ixMwy-0001lZ-La; Thu, 30 Jan 2020 22:26:32 -0500 Received: from omr1.cc.ipv6.vt.edu ([2607:b400:92:8300:0:c6:2117:b0e] helo=omr1.cc.vt.edu) by shelob.surriel.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92.3) (envelope-from ) id 1ixMwv-0001lT-QM for kernelnewbies@kernelnewbies.org; Thu, 30 Jan 2020 22:26:29 -0500 Received: from mr2.cc.vt.edu (mr2.cc.vt.edu [IPv6:2607:b400:92:8400:0:90:e077:bf22]) by omr1.cc.vt.edu (8.14.4/8.14.4) with ESMTP id 00V3QNC8011566 for ; Thu, 30 Jan 2020 22:26:28 -0500 Received: from mail-qv1-f70.google.com (mail-qv1-f70.google.com [209.85.219.70]) by mr2.cc.vt.edu (8.14.7/8.14.7) with ESMTP id 00V3QIfs028191 for ; Thu, 30 Jan 2020 22:26:23 -0500 Received: by mail-qv1-f70.google.com with SMTP id b8so3578187qvw.3 for ; Thu, 30 Jan 2020 19:26:23 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:in-reply-to:references :mime-version:content-transfer-encoding:date:message-id; bh=bz3TxiwCfLS9I0nGNI66FDo1ZSne6Zl5++XQaTSA8QQ=; b=LabYuDHr1XFesYu0p8c6LFR0KCgVrGc2tGXZqeARiYQdA7Q/lAlgukdY9OM5sN1kBH KIXXgPSLB4TlTgMnyZjLggGwkHWAcSiWtu6JqdPN5cL6PvSxjocDG6yI/UWzdC9+qPE6 HTqsyZ/7gINXhcr0s4InjvfJYF5Pse+X6OKWcTKBrmNnIkyY+sePwUVm9eTphKdn9Vjy FZI8KEks0bHknLEDaU59o3sAJRT3IRmcDTtIbUwQHUJXZ2VuQ1AA6KwFAXRMIoDc6I55 RdcvX6qmXO3jZ8v7RGs40D8SFx0v8uIO6UaZ1Z6xUNvyS97vMZqHka5yKs97dL6n+hIf halw== X-Gm-Message-State: APjAAAWHJG/6Y1ehoTx1v8EjWgX60YfDh9497HLrXEvucTdqyPcmZf0w m6L9+dA7o0s9UMrpRARBcwsZ6MaBHWGyqQzxiyWlhmPtwFv0o5+JNHuuJUTb91TcHevyr0IdRvz v9+2pBSQ4PdE1jeq2QE4lUpVNQ6cdDcSMH5SKYeE= X-Received: by 2002:a0c:e150:: with SMTP id c16mr8385100qvl.51.1580441178228; Thu, 30 Jan 2020 19:26:18 -0800 (PST) X-Google-Smtp-Source: APXvYqzmIMRbMFVBtof6CfBPXTwk2d5ekl8GjCH4UWYBBGQsxqtCub2fBPteE3QoLipzGEVGTIW+LQ== X-Received: by 2002:a0c:e150:: with SMTP id c16mr8384855qvl.51.1580441173031; Thu, 30 Jan 2020 19:26:13 -0800 (PST) Received: from turing-police ([2601:5c0:c001:c9e1::359]) by smtp.gmail.com with UTF8SMTPSA id w2sm4245550qtd.97.2020.01.30.19.26.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Jan 2020 19:26:11 -0800 (PST) From: "Valdis Kl=?utf-8?Q?=c4=93?=tnieks" X-Google-Original-From: "Valdis Kl=?utf-8?Q?=c4=93?=tnieks" X-Mailer: exmh version 2.9.0 11/07/2018 with nmh-1.7+dev To: Lukas Straub Subject: Re: Ordering guarantee inside a single bio? In-Reply-To: <20200130151617.58d57aa4@luklap> References: <20200126130738.0fdc47d6@luklap> <305354.1580146078@turing-police> <20200127192243.1b035b5b@luklap> <47803.1580329717@turing-police> <20200130151617.58d57aa4@luklap> Mime-Version: 1.0 Date: Thu, 30 Jan 2020 22:26:10 -0500 Message-ID: <37133.1580441170@turing-police> Cc: 오준택 , kernelnewbies@kernelnewbies.org X-BeenThere: kernelnewbies@kernelnewbies.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Learn about the Linux kernel List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============1237943622244013228==" Errors-To: kernelnewbies-bounces@kernelnewbies.org --===============1237943622244013228== Content-Type: multipart/signed; boundary="==_Exmh_1580441170_15018P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit --==_Exmh_1580441170_15018P Content-Type: text/plain; charset=us-ascii On Thu, 30 Jan 2020 15:16:17 +0100, Lukas Straub said: > No, csum_next (and csum_prev) is a whole sector (i.e. physical block) > containing all the checksums for the following chunk of data (which > spans multiple sectors) Oh, OK. That works too.. :) > Regarding the ordering guarantee, I have now gathered that the kernel > will happily split the bio if the size is not optimal for the hardware > which means it's not guaranteed - right? And if the kernel doesn't split it and reorder the chunks, the hardware will happily do so - and lie to you the whole way. Ever since the hardware people realized they could get away with lying about turning off the writeback cache, it's been more and more of a challenge to guarantee correct performance from storage subsystems. --==_Exmh_1580441170_15018P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Comment: Exmh version 2.9.0 11/07/2018 iQIVAwUBXjOeUQdmEQWDXROgAQKDqxAAse58cR8XWeuj4sftz1udcB0JPKSFMtwZ uZI1TpAuM8mMUjmovqeH9u5/K2zwpWRBJbVnioLKtT57Jva88DHm+lPnghL4zwYl eVvbAzvMPxYf12AMmj5SiXT6mub9qzOWdzivtJUTrkN9Nz9MuND3ch571lp9QZUl Q1VTRiz58pnaaJn8WrhGG1m6VjjZwTqXe7CC2RJRqpQz5rq8qXUyNDHfuBy3SjsP Y9yI17bO3Z2081NHCmZxNS7r3jDU6QRJbcuVIR2XT8490N1NPA3oTsIUcoGL+OYL UBaPKCd79wJWuXfhf/My0ZQXUDfFkP2qc/mHZG6/GGqwco8zP8vHi1WTFRM/aCRG 5itKOk0BwiYO1YyK1/L6aSKpjQPrKG9vrQddOQ/mucG8+iDfSRfljnmqiu0uf7dY hxTpa1A4dFV2yAWtnKXEGmJ69ZODjST1J5mTwTBiYtfkvVu1yhY24Dw9+oZiXEIe 1ZFMULZzaIoA2m1vDST1xXNWkglT+MDcKJvjToV20IRh0Fpu0o2XKGQF5/DcyygS 98gvGBK7nJ27ZqgP+5jiF6g4viHdifh6kNJhR7sV8F0Czblzf08+kWAkrf0M7Nuh /h7fibsAlE+diU7oP+m4cTIbx8nMc/Co+c7WkDPmOeA+T5jpkX7mL+04iDrQtG2h swifAEGev1s= =k5Vo -----END PGP SIGNATURE----- --==_Exmh_1580441170_15018P-- --===============1237943622244013228== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies --===============1237943622244013228==--