From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1163968AbdAIRfe (ORCPT ); Mon, 9 Jan 2017 12:35:34 -0500 Received: from mail-qk0-f193.google.com ([209.85.220.193]:33148 "EHLO mail-qk0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1163113AbdAIRfa (ORCPT ); Mon, 9 Jan 2017 12:35:30 -0500 Date: Mon, 9 Jan 2017 12:35:18 -0500 From: Tejun Heo To: Shaohua Li Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, axboe@fb.com, vgoyal@redhat.com Subject: Re: [PATCH V5 04/17] blk-throttle: configure bps/iops limit for cgroup in low limit Message-ID: <20170109173518.GF12827@mtj.duckdns.org> References: <04bae2f6239c13d3160d7c0196c97217c5e4b4c3.1481833017.git.shli@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <04bae2f6239c13d3160d7c0196c97217c5e4b4c3.1481833017.git.shli@fb.com> User-Agent: Mutt/1.7.1 (2016-10-04) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Thu, Dec 15, 2016 at 12:32:55PM -0800, Shaohua Li wrote: > each queue will have a state machine. Initially queue is in LIMIT_LOW > state, which means all cgroups will be throttled according to their low > limit. After all cgroups with low limit cross the limit, the queue state > gets upgraded to LIMIT_MAX state. As with the previous patch, I don't think it's correct to default to MAX for LIMIT_LOW and then enforce it. Without specific configuration, a cgroup should always be above below (so, no latency requirement) and below max (no hard limiting). Thanks. -- tejun