From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752719AbbDACzu (ORCPT ); Tue, 31 Mar 2015 22:55:50 -0400 Received: from mgwkm02.jp.fujitsu.com ([202.219.69.169]:55635 "EHLO mgwkm02.jp.fujitsu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751141AbbDACzt (ORCPT ); Tue, 31 Mar 2015 22:55:49 -0400 X-SecurityPolicyCheck: OK by SHieldMailChecker v2.2.3 X-SHieldMailCheckerPolicyVersion: FJ-ISEC-20140219-2 Message-ID: <551B5E0F.1020302@jp.fujitsu.com> Date: Wed, 1 Apr 2015 11:55:11 +0900 From: Kamezawa Hiroyuki User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Tejun Heo CC: Gu Zheng , , , , , Subject: Re: [PATCH 0/2] workqueue: fix a bug when numa mapping is changed References: <1427336275-32066-1-git-send-email-guz.fnst@cn.fujitsu.com> <55137935.5080301@jp.fujitsu.com> <55139340.8070201@cn.fujitsu.com> <20150326151850.GD1953@htj.duckdns.org> <551436F2.5020804@jp.fujitsu.com> <55191C3D.8070800@cn.fujitsu.com> <551A3A01.7030707@jp.fujitsu.com> <20150331152822.GE9974@htj.duckdns.org> In-Reply-To: <20150331152822.GE9974@htj.duckdns.org> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-SecurityPolicyCheck-GC: OK by FENCE-Mail X-TM-AS-MML: disable Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/04/01 0:28, Tejun Heo wrote: > Hello, Kamezawa. > > On Tue, Mar 31, 2015 at 03:09:05PM +0900, Kamezawa Hiroyuki wrote: >> But this may be considered as API change for most hot-add users. > > Hmm... Why would it be? What can that possibly break? > Now, hot-added cpus will have the lowest free cpu id. Because of this, in most of systems which has only cpu-hot-add, cpu-ids are always contiguous even after cpu hot add. In enterprise, this would be considered as imcompatibility. determining cpuid <-> lapicid at boot will make cpuids sparse. That may corrupt exisiting script or configuration/resource management software. >> So, for now, I vote for detemining ids at online but record it is a good way. > > If we know the information during boot, let's please do it at boot > time by all means. I basically agree. Just thinking influence of this small imcompatibility of forcing ideal way because of my standing point. Thanks, -Kame