From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932505Ab3EBReg (ORCPT ); Thu, 2 May 2013 13:34:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:64112 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758632Ab3EBRee (ORCPT ); Thu, 2 May 2013 13:34:34 -0400 Date: Thu, 2 May 2013 13:34:28 -0400 From: Vivek Goyal To: Tejun Heo Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org, lizefan@huawei.com, containers@lists.linux-foundation.org, cgroups@vger.kernel.org Subject: Re: [PATCHSET] blk-throttle: implement proper hierarchy support Message-ID: <20130502173428.GA4771@redhat.com> References: <1367455189-6957-1-git-send-email-tj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1367455189-6957-1-git-send-email-tj@kernel.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 01, 2013 at 05:39:18PM -0700, Tejun Heo wrote: [..] > While this patchset contains many patches, the implementation is > pretty straight-forward. throtl_grp's form a tree anchored at > throtl_data and bios climb the tree as they get dispatched at each > level. The bios which reach the top of the tree - throl_data - are > issued. Have a question here. Looks like when bio climbs from child group to parent group, then parent group slice starts fresh if parent was empty. So if we have a parent with 1MB/s limit and a child with 1MB/s limit and a bio gets queued in child, then looks like effective IO rate would be .5MB/s and not 1MB/s? IOW, when child gets queued, we should start time accounting for all parents in the hiearchy too. Thanks Vivek