From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754219AbdCBIMJ (ORCPT ); Thu, 2 Mar 2017 03:12:09 -0500 Received: from cn.fujitsu.com ([59.151.112.132]:24570 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750733AbdCBIMG (ORCPT ); Thu, 2 Mar 2017 03:12:06 -0500 X-IronPort-AV: E=Sophos;i="5.22,518,1449504000"; d="scan'208";a="16130926" Subject: Re: [PATCH v2 1/4] Revert"x86/acpi: Set persistent cpuid <-> nodeid mapping when booting" To: Thomas Gleixner References: <1487580471-17665-1-git-send-email-douly.fnst@cn.fujitsu.com> <1487580471-17665-2-git-send-email-douly.fnst@cn.fujitsu.com> CC: , , , , , , , , , , , , , , From: Dou Liyang Message-ID: Date: Thu, 2 Mar 2017 15:58:27 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.167.226.106] X-yoursite-MailScanner-ID: 9B63C48A2942.AA608 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: douly.fnst@cn.fujitsu.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi tglx, Thank you very much for your guidance! It makes me more profound understanding of the changelog. And you also rewrote my changelog for giving me an example. I am so grateful that you can help me so carefully. Once I heard the charm of the open source community, Now i can really feel it. I love it so much. I will try to improve myself and help others. :) Thanks, Liyang. At 03/01/2017 06:51 PM, Thomas Gleixner wrote: > On Mon, 20 Feb 2017, Dou Liyang wrote: > >> Currently, We make the mapping of "cpuid <-> nodeid" fixed at the booting time. >> It keeps consistent with the WorkQueue and avoids some bugs which may be caused >> by the dynamic assignment. >> >> But, The ACPI table is unreliable and it is very risky that we use the entity >> which isn't related to a physical device at booting time. >> >> Now, we revert our patches. Do the last mapping of "cpuid <-> nodeid" at >> hot-plug time, not at booting time where we did some useless work. >> It also can make the mapping of "cpuid <-> nodeid" fixed and avoid excessive >> use of the ACPI table. >> >> The patch revert the commit dc6db24d24: >> "x86/acpi: Set persistent cpuid <-> nodeid mapping when booting". > > That changelog needs some massaging. Something like this: > > The mapping of "cpuid <-> nodeid" is established at boot time via ACPI > tables to keep associations of workqueues and other node related items > consistent across cpu hotplug. > > But, ACPI tables are unreliable and failures with that boot time mapping > have been reported on machines where the ACPI table and the physical > information which is retrieved at actual hotplug is inconsistent. > > Revert the mapping implementation so it can be replaced with a less error > prone approach. > > This clearly describes: > > 1) The context > > 2) The problem > > 3) The solution (revert) > > You don't have to explain what the new solution will be in the changelog of > the revert. For the revert it's only relevant WHY we do the revert. > > Please avoid writing changelogs in 'we' form. Write it pure technical, like > a manual. > > Also avoid phrases like: "The patch/This patch". We all know already that > this is a patch, otherwise it wouldn't have been sent. > > Documentation/process/submitting-patches.rst says: > > Describe your changes in imperative mood, e.g. "make xyzzy do frotz" > instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy > to do frotz", as if you are giving orders to the codebase to change > its behaviour. > > Thanks, > > tglx > > > >