From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753574AbaJJLBD (ORCPT ); Fri, 10 Oct 2014 07:01:03 -0400 Received: from mail-pd0-f178.google.com ([209.85.192.178]:44833 "EHLO mail-pd0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751306AbaJJLBC (ORCPT ); Fri, 10 Oct 2014 07:01:02 -0400 Message-ID: <5437BC67.2010700@gmail.com> Date: Fri, 10 Oct 2014 19:00:55 +0800 From: Wanpeng Li User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Peter Zijlstra CC: Wanpeng Li , Ingo Molnar , Juri Lelli , Kirill V Tkhai , Steven Rostedt , linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched/deadline: do not try to push tasks if pinned task switches to dl References: <1412908997-15396-1-git-send-email-wanpeng.li@linux.intel.com> <20141010101016.GJ10832@worktop.programming.kicks-ass.net> <5437B462.4050102@gmail.com> <20141010105614.GA3343@worktop.programming.kicks-ass.net> In-Reply-To: <20141010105614.GA3343@worktop.programming.kicks-ass.net> Content-Type: multipart/mixed; boundary="------------020907010901020206010006" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------020907010901020206010006 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 于 10/10/14, 6:56 PM, Peter Zijlstra 写道: > On Fri, Oct 10, 2014 at 06:26:42PM +0800, Wanpeng Li wrote: >> 于 10/10/14, 6:10 PM, Peter Zijlstra 写道: >>> On Fri, Oct 10, 2014 at 10:43:17AM +0800, Wanpeng Li wrote: >>>> As Kirill mentioned(https://lkml.org/lkml/2013/1/29/118): >>>> | If rq has already had 2 or more pushable tasks and we try to add a >>>> | pinned task then call of push_rt_task will just waste a time. >>>> >>>> Just switched pinned task is not able to be pushed. If the rq had had >>>> several dl tasks before they have already been considered as candidates >>>> to be pushed (or pulled). This patch does the same behavior as rt class >>>> which introduced by commit 104479 (sched/rt: Do not try to push tasks >>>> if pinned task switches to RT). >>> Checkpatch rightly complains: >>> >>> ERROR: Please use 12 or more chars for the git commit ID like: 'commit 10447917551e ("sched/rt: Do not try to push tasks if pinned task switches to RT")' >>> #12: >>> which introduced by commit 104479 (sched/rt: Do not try to push tasks >> I also got this warning before send out the patch, however, I check 6 chars >> is enough for this commit. Anyway, I will send a newer version later. > It is currently, it might not be in the future. I've already had hash > collisions with 8 char hashes. And the fact thats it in the changelog > means it can (and therefore) will be referenced at some point in the > future. If by that point there is a collision... Got it, thanks for your pointing out. 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