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; 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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.