From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754621AbcJZLew (ORCPT ); Wed, 26 Oct 2016 07:34:52 -0400 Received: from mx2.suse.de ([195.135.220.15]:33075 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752681AbcJZLeu (ORCPT ); Wed, 26 Oct 2016 07:34:50 -0400 Date: Wed, 26 Oct 2016 13:34:43 +0200 From: Jan Kara To: Christoph Hellwig Cc: Paolo Valente , Jens Axboe , Tejun Heo , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, ulf.hansson@linaro.org, linus.walleij@linaro.org, broonie@kernel.org, hare@suse.de, arnd@arndb.de, bart.vanassche@sandisk.com, grant.likely@secretlab.ca, jack@suse.cz, James.Bottomley@HansenPartnership.com Subject: Re: [PATCH 00/14] introduce the BFQ-v0 I/O scheduler as an extra scheduler Message-ID: <20161026113443.GA13587@quack2.suse.cz> References: <1477474082-2846-1-git-send-email-paolo.valente@linaro.org> <20161026101903.GA22361@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161026101903.GA22361@infradead.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? Honza -- Jan Kara SUSE Labs, CR