From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755031AbcJZPFc (ORCPT ); Wed, 26 Oct 2016 11:05:32 -0400 Received: from mail-cys01nam02on0076.outbound.protection.outlook.com ([104.47.37.76]:54928 "EHLO NAM02-CY1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754126AbcJZPFX (ORCPT ); Wed, 26 Oct 2016 11:05:23 -0400 Authentication-Results: spf=pass (sender IP is 63.163.107.21) smtp.mailfrom=sandisk.com; linaro.org; dkim=none (message not signed) header.d=none;linaro.org; dmarc=bestguesspass action=none header.from=sandisk.com; X-AuditID: 0ac94369-babff7000001694f-63-5810c398ae07 Subject: Re: [PATCH 00/14] introduce the BFQ-v0 I/O scheduler as an extra scheduler To: Jan Kara , Christoph Hellwig References: <1477474082-2846-1-git-send-email-paolo.valente@linaro.org> <20161026101903.GA22361@infradead.org> <20161026113443.GA13587@quack2.suse.cz> CC: Paolo Valente , Jens Axboe , Tejun Heo , , , , , , , , , , From: Bart Van Assche Message-ID: <4ed3e291-b3e5-5ee3-6838-58644bd3d99b@sandisk.com> Date: Wed, 26 Oct 2016 08:05:11 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20161026113443.GA13587@quack2.suse.cz> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrOIsWRmVeSWpSXmKPExsXCddJ5ke6cwwIRBrf6uC3+TjrGbrH6bj+b xdSHT9gsXp3ZyGaxZ9EkJovTExYxWcye3sxksbGfw2LKn+VMFntvaVtc3jUHqOrPXiaLX8uP MlocXxvuwOfx+9ckRo9pk06xeWxeoeVx+Wypx6ZVnWwed67tYfP4+VLH48yCI+wem09Xe3ze JBfAFcVlk5Kak1mWWqRvl8CVcW73WfaCo5wVb75MZG9gPMrexcjJISFgIvH5+FfWLkYuDiGB pUwSp79eYoNwtjFKzJ38kAWmat25yYwQicWMEise3WDuYuTgEBYIlXi0RROkRkTASWL7lFYW iJpZjBKbmpeDTWIW+M8k0f37FxNIFZuAkcS39zPBpvIK2Ekc+PEY7A4WAVWJoxcfs4HYogIR Epu+zoGqEZQ4OfMJmM0JdMW5zasZQRYzC9hLPNhaBhJmFpCX2P52DjPILgmBJWwSjaePMoIk hATUJU4umc80gVF4FpJRsxDaZyFpX8DIvIpRLDczpzg3PbXA0FSvODEvJbM4Wy85P3cTIyQ6 M3cw3n3ifYhRgINRiYe3Ya1AhBBrYllxZe4hRgkOZiURXsOjQCHelMTKqtSi/Pii0pzU4kOM 0hwsSuK8bve+hAkJpCeWpGanphakFsFkmTg4pRoYNVJuHn3F9EZwcafPu50X13bt+hDqLBW6 5nCN6zflhXoRC9/UX/zP+NhT6bGBvzzjvkfTggJ1l6zofXq367dT7b8JolrPmdNfpmd1u6g5 bnp74WlfNsfymNOvnkV2Pz0z83DdPr57n1WS1QNMjY++sRA5kHo8sWaH/+3X6qvufxcOumfG dCWrTImlOCPRUIu5qDgRAI1XotfKAgAA X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrBLMWRmVeSWpSXmKPExsXCtZGTTVfrmECEQfMxFou/k46xW6y+289m cfBnG6PF1IdP2CxendnIZrFn0SQmi9MTFjFZzJ7ezGSxsZ/DYsqf5UwWe29pW1zeNQeo6s9e Jotfy48yWhxfG+7A7/H71yRGj2mTTrF5bF6h5XH5bKnHplWdbB53ru1h85i25jyTx8+XOh5n Fhxh99h8utrj8ya5AO4oLpuU1JzMstQifbsEroxzu8+yFxzlrHjzZSJ7A+NR9i5GTg4JAROJ decmM3YxcnEICSxklPi4ZSGQw8EhLBAq8WiLJkiNiICTxPYprSwQNbMYJTY1L2cDcZgFXjNJ fP+7iQmkik3ASOLb+5ksIDavgJ3EgR+PwTawCKhKHL34mA3EFhWIkNj0dQ5UjaDEyZlPwGxO oCvObV7NCGIzC9hK3Jm7mxnClpfY/nYO8wRGvllIWmYhKZuFpGwBI/MqRrHczJzi3PTMAkMj veLEvJTM4my95PzcTYyQuInawXh9ovkhRiYOTqkGxmMP9n4zSVN7GTj7RPWE7RmsC61b0h9Y 7vTjC2Dh8RNXX3zu6Fqe+7mW75QZnru/31z13ELy4t6UK2bdWzZK2+3WWGpms1zxtNPxWcxf f/Ro+WxT0TC74B1rpWPZZJvZpGbt8NT+Y/Rq3qnmZyfsOhVb/68p4alL10TetCi7Q4+OrfAO rNW7pcRSnJFoqMVcVJwIAJIYjNFLAgAA X-EOPAttributedMessage: 0 X-MS-Office365-Filtering-HT: Tenant X-Forefront-Antispam-Report: CIP:63.163.107.21;IPV:NLI;CTRY:US;EFV:NLI;SFV:NSPM;SFS:(10009020)(6009001)(7916002)(2980300002)(438002)(24454002)(377454003)(189002)(199003)(377424004)(54356999)(6666003)(23746002)(8936002)(81156014)(305945005)(97736004)(8676002)(92566002)(106466001)(5001770100001)(7846002)(356003)(64126003)(50986999)(81166006)(4001350100001)(50466002)(68736007)(2270400002)(87936001)(36756003)(65806001)(230700001)(189998001)(65956001)(33646002)(47776003)(76176999)(11100500001)(7416002)(586003)(5660300001)(31686004)(2906002)(65826007)(86362001)(77096005)(31696002)(2950100002)(69596002)(83506001)(53416004)(4326007)(626004);DIR:OUT;SFP:1101;SCL:1;SRVR:BLUPR02MB264;H:milsmgep15.sandisk.com;FPR:;SPF:Pass;PTR:InfoDomainNonexistent;MX:1;A:1;LANG:en; X-Microsoft-Exchange-Diagnostics: 1;BL2FFO11FD014;1: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 X-MS-Office365-Filtering-Correlation-Id: 2d6e398c-6259-4268-753e-08d3fdb18085 X-Microsoft-Exchange-Diagnostics: 1;BLUPR02MB264;2:l5xN3r2CqlV0Wf0qEBdTR8EOC7+pPhjw57jScMsb8vcaqusBrDHgv4tlSVp4o/+A7mxCwYk7k0c+cYzuZJ8YG3Qhmv7e2giPow3sRsVqcMDszfecs811hRrQIMXHXtJHBbfqNbxqipRNt8tR8WWvatNWO8XsiSFD1XQ5DJpc8lkmZg23MAWUbNXxXkaBqx7FqTwoG+t9qSK7Hdn3w3KwVA==;3:PBckJpx5Vv2wfUQSg3d4+wS2O1vkAzLeH8L/Kkr9sLvaaSSPTyGWl7jrxzBQfg+EVt5iOuF19UbkWWkH8DLyjMXmsaofdEpmn9PmaeqKYC+O/vuVcatIBPkHlHxVBCojTlXIbUw4qj6iLvLMlcjK61Jh224j8vHI1UKWEElCTnS0Q/P8GpF2IIKSnm3SsMPH8H2kf3tGV5uA6eO2AMgTxMGh9aTZzPs/MDJ8v6Rwm6//QkKq37gMP6l2By6yL5nxYsV+w4m9toR1ZyHgj047MU3Iji6atCcpjxi7dYR+aMM=;25:UkNatwc6mKFlg+udLZa0eS8VV6/mig4EAQkIt7ONP6wJBErcYt71UvWFlyjRXHM8EoGUwjU/vQ8dcipP1SLDRpFpopko4nOwi3gtUFcv3EgqJwUhB/ksdJASa4xYdxLzOaObZLNrWc8sKQC5aNaSSV9g3RQG4ynACosFjGJt87jc3RrJ3SPwnLQNI4y7blQa3V+gTDAt1YO0Hdb6hqsq69Zr3bVxtOsiQrwa1uqO1Cqn1YOwM7yv3vR2sNJu5W2RArJMcFZ+4y6O4JdALZW9VhoXqi9Yyuwx701vAZl2IUmhGTn4OxSaSsc9XanAY8SRjaVmf/GAwA1zD1FpWNhiJn95Sf2KzavOaxqYXEzDeIX8dkGlcoFAbNASwh8SqKg3uBZWEi7EvJGfXUhWfwBUp2Uid+P0xbUOXWXRotKnV2q68utKEfZy78+19Ac+KTQZ X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:(8251501002);SRVR:BLUPR02MB264; X-Microsoft-Exchange-Diagnostics: 1;BLUPR02MB264;31:ERtqil5tvCVR9upXrKB92bpFsSMe8g6Bm7XuaH3ooRMuhpsox26lblK0LDif/UbATawKZe2BcwdsA/XBLFyFICquOIDSKbeQbY8hQN+ZIMH+h7+3SqRoTjBpzhxUkQl4f+We8KtrS+pqkp1NiH0CwsOfe2lVhsZTtirHeqsM9wqwoCM1MIeCmdUQ4petsehdgGPaG33U26VcC1H2hjfobS7WvCblhryXjD7XP9PiKi82fYir9Ivv2AorGNmHWxqz;20:w1W8/JmSNM1jR6+MPbTn37k+IRmCoKfMjvHs5xL6UTqCZsEXO7XiiG/+qkK4vFRYMjwcscT10vQkIclSlLR3ZbneYsJ4syZMy/mVsC4mqAsSWlRG8YuSzw05Uw+CKa0nHtaGpvVY4aG2iIJy6Ro0zHHSXo7lNlysr2Ay37PWvTITmW1XR/NK+PEGPSzQfC8Fm9hSXRWmVdoFxNzWH6G5X0giIx8o49CMO2kIPCgCpCrMBQrZWux615I7OaaQT26e7qlS6HmaHKoIZgpatkuV/98rOh8+6Qy/sNQAtxf0iSvZN0NzYvcd0uNrILKGkrQxMYAMcbsjHc5JTuf7mGZtNg9q8lf16o9ztWDWBxPuhG8Brz0xjEnZyEL/3tT/BHUWqcZGlBokWcEjetGke0WYOarOOHb3T1zMy66i+tnJvH1ZtGHe9xcJrg9iIfSgR9prugRRhtFHFgxyiU6vTRUcIvFvGCDhEMnzp2SckZff3VEtq3iTnRzDjv59sbZ0T7pi X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:; X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(6040176)(601004)(2401047)(13016025)(13018025)(5005006)(8121501046)(10201501046)(3002001)(6055026);SRVR:BLUPR02MB264;BCL:0;PCL:0;RULEID:;SRVR:BLUPR02MB264; X-Microsoft-Exchange-Diagnostics: 1;BLUPR02MB264;4:cZ4u7lHe1tKOuf7kcq4FrQ1Vfxe93lf3kIIkOJuEdLyULdYpL9LCCwj1xfe94owA8jmpmz+Kq+YHjtc0W+35vS+rBpD0CvoNxLk9OsvBBsjx7t0ul4D1AwvWSt5tDDZgbqc0ViqK6xOBKIfn/oTbTSxLFMiC+RDVL4+15vpf80luLJxJmue7Fo7Ml6PIyqp9t+FQf91AFiRK9HHM3lTOUVe9rcIJKF7I5UbLCpQ7FICYyOIV9ov9uTgKupaVgZTUNjEq6LsdoUY17CCTgpEUeVkh/y/JXMFvYUw+Pm6Gs/nz08QVDz0TNPI2CUpb6+Rt2V7RnAt5iTMgrzH67eQol5nsF+rZEaWgvswRjpusL6Au3Onmyayj1YcxoUsQmV1T55pbtYZ+I+M4v/eUD13nxge2hjkBzxi0Sf1Qjft/2YzjndYwXsLEUB/MywZHG/0/Ke2dtCHla/tArSkuA02Qtw== X-Forefront-PRVS: 0107098B6C X-Microsoft-Exchange-Diagnostics: =?Windows-1252?Q?1;BLUPR02MB264;23:wpWyW1c645rJzYFlEWYuTXRE2uyUv3WxhcbYCe?= =?Windows-1252?Q?/TbMOIJA4eXnQSHBXstpGzqTct8kf7Ekt9KfncCqJNj4iok5Em5++Zka?= =?Windows-1252?Q?jG0ySCnz0q6FXkPvb9cbCem6CSBGhlSe517xJLgiaZG72cIbDsYoUSsS?= =?Windows-1252?Q?j3YJ/1SmqZLXPanSD15dWIqvQ6JnAlRZYb/0chvygmfRmBQkl0CWkRbd?= =?Windows-1252?Q?Mb7vqTzQTAn/vqLCxIhXMzK585xXcsQDXgLM4hXvcaAEIylK8RFOa7us?= =?Windows-1252?Q?vRnPO/JnOSkCpwVI7kKran3JCHpyC9NxP3wQkfHx41M67TmAELE9sX3n?= =?Windows-1252?Q?OKUCJ2/VcMaJHa5aAItd2lNImQXN4YpFQkz1rWUxeHuh1oY8VKpNtxQS?= =?Windows-1252?Q?Yn6Z+zQtguH6OxhgOZuhenIc4/nZoqN/fBR7peUsxp2leR6FJjywzwBx?= =?Windows-1252?Q?upVQe1oT3PJ2Z2nbRKbpbQ5v/A+miz8wrCHz8fUxziq0nl45ElcfKH9G?= =?Windows-1252?Q?wHhkLV8U2YaV5q3RaqcOJ17P970vd/XiXdold+lV1zdBD0SmH5h5fW/s?= =?Windows-1252?Q?rk+EfmsFFxSOKPBSqtdSGH9CRkAWy8d3ZBvdK0rQxSxJPX6kUol86d/d?= =?Windows-1252?Q?GFKJZRmzCnhbxs7KY5vEX8MjxzCI7/djFy+Kybv8Lln2paN2yYQCDb21?= =?Windows-1252?Q?ygrLgEc6sB76fgYzPUg3WPZccXqJKT//u4+hFMk/6jZKsenazmdi3CnH?= =?Windows-1252?Q?qsK/XEI/CKMMpZx9v3Z/XVptrUn0UrbEFzU3nf9e8Jy0//rmAgRKEyvJ?= =?Windows-1252?Q?1x6GQNXPPEY/YSYiTFHNUGxii+rVQnaraWDeOjP2N/OTF01OOe89zfdM?= =?Windows-1252?Q?8rlYylek1piUzFYh+Iuz8U9QkLF/iuJhXL9oGz0LzrHOTNilFl+qE04X?= =?Windows-1252?Q?bjRh7XJ15x1xrcc+EFWNdev1AK+QCrzZwQrDrmoutkiWigSQ13SThJGq?= =?Windows-1252?Q?uYMaQIl+QEwIKmexr/Q/3/3kLuyTswDM+ZcCQPB/2om31gV0HLiIJ2oB?= =?Windows-1252?Q?TqufF8SfmEvAxb8ITB9wUXknXPo1oyPPRJO0O69Wi4sta+dJui00eUAA?= =?Windows-1252?Q?tgyhq+c0dX216E6ThjFUI2b4oDXWmjNKQ3JQKetjF8SoriZvftBG0h06?= =?Windows-1252?Q?UBqDnHvw+rIJegKW1ct1XlCgFLCl8P0pmBBksk5AjAiinfG3pzZQc1kb?= =?Windows-1252?Q?zCNnaQAAfschMu0JeoCOEWWXA2q2ttdrfK0VRCQaFUktbK2YO23iAfEK?= =?Windows-1252?Q?tHlODW6lDBoTLo7B4AU57sf3NonpekQBfbGlMhGw30LrCKh9HO3ylZM4?= =?Windows-1252?Q?gNO+mVed0fZhb6vWFiN0yonKaIaNX52g=3D=3D?= X-Microsoft-Exchange-Diagnostics: 1;BLUPR02MB264;6:utBq29soUeP4JlpJxV2b8TEYZ0r/blZRNT3KbMstUwuBg95Za7BPB8+mZ/Es0PzqjP6xNy8YGZ3VuWHTJyyeJhLBr6K3kgE0jeExkT3qncNzSldiL88XZjYokjAs7ZM/Kics/gWTUEWYCxgv1CVh39zn3fA+77va3o5HnoauMIu0QRAu7tJo1liPbVDHyqqJCv6l0ChV8CUkHyGcidQXtHvWDQ5/O8wodIEHu9kk6K/22mqy56fSVpO7vTBrnkhMKORWOBohm4IOZ9eDXLcpJo8yy4LCIbN1YQOD8Tp/5eOhqU900Nw25EINmYfQ6D3LQ3RmhFrXfw0wgkXFBdjSNPnDOOSN2zXqG1PKuMI3+cU=;5:FLf/J/063yVlIDQWxnmhtvXohWdImsQQgPSHLtCBUKQvLW7JNqRrCbo8ZCgxv2lVc+52X4l3eFXoHv5ZmIzEjYWiYB9a/XKYzkWmkoJ32lKb1fPdHPeXULQwLmSNmyN/4q4/4TcJMZaakgVOAWYU8Q==;24:ZE2v0OkHmlYAAQQy7NsB/tF4SmDa6GOLr6aG0Aqx3u5j2jJXsaSCBShDfJ6FnRtyItNewi4KMTJHCXLMgX8vXiv0SlKi5lrxFZ6kG6dYnBM= SpamDiagnosticOutput: 1:99 SpamDiagnosticMetadata: NSPM X-Microsoft-Exchange-Diagnostics: 1;BLUPR02MB264;7:XTk3iZf1J61iCvNQ0pVYyYojrmo8awhTTcmX8qLNuDe8HPBISluNzD9sdAs6LS4eLLPVJyAYwJaFa2+2WQGO69t+XUwyZK1wUzh+CMw+cDpHlXkbkwvolGcVVjsf9bAhuZBbHXHnfpM/qZLCf6wxXfF5gRUNp0aYFL8yivQ5Dckd3O/msbv0aixoByMiOsO0tOZvSyIt98yLAa1/pL4bxrv7IHwXE+ozUXg1p2e6bP9kKfVlkjLr1sz73IgrDV7kH6H6TvCEapKgl6W5I7YUOjnH09FFOLjm3wbJoVtAhdtMDAYBj8U6INFFu/fGR0se9c1q6SDYDEB1u8eiL3RTWWygJ+Hw7true3tSMbh+Ovk=;20:Z0N+NFNyjp2PCrgO8DzNV6BadGJ2si8G8mxe9U6R8F/Nd57JXC9c8C9oab3uvAtzgPvGInrc3wS8AtlV+/SmdNkmDfd/iDi9j4TbHQfMs7ZlsbDb+ZQsHOEhaA0Bmp0kZ9mHxjOtQO+M2cPI4iIGq4SAgTKLSVeWYWpR9VNqsXHYLJk5FvtnJQD4yo9POv0Jnhc/uwykbHANnGqmEZyk79J28TCW4ppF03vpbBz3b0aAAdr1E/MIaq0AF+rQryVK X-OriginatorOrg: sandisk.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Oct 2016 15:05:18.2600 (UTC) X-MS-Exchange-CrossTenant-Id: fcd9ea9c-ae8c-460c-ab3c-3db42d7ac64d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=fcd9ea9c-ae8c-460c-ab3c-3db42d7ac64d;Ip=[63.163.107.21];Helo=[milsmgep15.sandisk.com] X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: BLUPR02MB264 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/26/2016 04:34 AM, Jan Kara wrote: > On Wed 26-10-16 03:19:03, Christoph Hellwig wrote: >> Just as last time: >> >> big NAK for introducing giant new infrastructure like a new I/O scheduler >> for the legacy request structure. >> >> Please direct your engergy towards blk-mq instead. > > Christoph, we will probably talk about this next week but IMO rotating > disks and SATA based SSDs are going to stay with us for another 15 years, > likely more. For them blk-mq is no win, relatively complex IO scheduling > like CFQ or BFQ does is a big win for them in some cases. So I think IO > scheduling (and thus place for something like BFQ) is going to stay with us > for quite a long time still. So are we going to add hooks in blk-mq to > support full-blown IO scheduling at least for single queue devices? Or how > else do we want to support that HW? Hello Jan, Having two versions (one for non-blk-mq, one for blk-mq) of every I/O scheduler would be a maintenance nightmare. Has anyone already analyzed whether it would be possible to come up with an API for I/O schedulers that makes it possible to use the same I/O scheduler for both blk-mq and the traditional block layer? Bart.