From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759466AbcJ1TOW (ORCPT ); Fri, 28 Oct 2016 15:14:22 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:60179 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754180AbcJ1TOU (ORCPT ); Fri, 28 Oct 2016 15:14:20 -0400 Date: Fri, 28 Oct 2016 15:12:32 -0400 From: Tejun Heo To: Peter Zijlstra CC: Tejun Heo , , , , , , , , , , , , Subject: Re: [PATCH 1/4] sched: move IO scheduling accounting from io_schedule_timeout() to __schedule() Message-ID: <20161028191231.GA29044@htj.duckdns.org> References: <1477673892-28940-1-git-send-email-tj@kernel.org> <1477673892-28940-2-git-send-email-tj@kernel.org> <20161028182712.GM3142@twins.programming.kicks-ass.net> <20161028190702.GL3157@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20161028190702.GL3157@twins.programming.kicks-ass.net> User-Agent: Mutt/1.7.0 (2016-08-17) X-Originating-IP: [2620:10d:c091:200::2:4b52] X-ClientProxiedBy: BN6PR12CA0013.namprd12.prod.outlook.com (10.168.222.23) To DM5PR15MB1532.namprd15.prod.outlook.com (10.173.222.135) X-MS-Office365-Filtering-Correlation-Id: d5f0a3ee-cad7-480f-46b5-08d3ff666469 X-Microsoft-Exchange-Diagnostics: 1;DM5PR15MB1532;2:RGvQd8hEfioM3lEu+Z+fNbrXFspX18XEWNZLRALT5/hVzE0p3ROliOuBmIy7Xdvvwv02XqZJoII4HKB1/In3FDJ/VXheKJ9+JhHD7idgRCYMcgjITnQNSOkaEHDFLACdmR+Rnr/ZZkfGJixtJe46c4hbWN6UC1NpnYCDIyW5n6ryjSgzjtLZyauiFDkVPvKnawylzF3Akgh3NBuk3FuzBg==;3:aaLkEn78kfDnWgI0UUPBvBIsa33g4ktF3Tk7n1CfxNW+6Xk8mf9AQ+gGzrqWeTn/lMYR1qnyO8NfA+t+d9oHFUng/orxjvoLqNXfEdoiTNxBNjPmQvotHmbHmeoWg2kWBN/ungN9Z81q48H4NpAFEQ== X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:DM5PR15MB1532; 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On Fri, Oct 28, 2016 at 09:07:02PM +0200, Peter Zijlstra wrote: > One alternative is to inherit the iowait state of the task we block on. > That'll not get rid of the branches much, but it will remove the new > mutex APIs. Yeah, thought about that briefly but we don't necessarily track mutex or other synchronization construct owners, things get gnarly with rwsems (the inode ones sometimes end up in a similar situation), and we'll probably end up dealing with some surprising propagations down the line. That said, getting such automatic propagation working would be great. Thanks. -- tejun