From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753705AbbCEBkl (ORCPT ); Wed, 4 Mar 2015 20:40:41 -0500 Received: from cn.fujitsu.com ([59.151.112.132]:57902 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753364AbbCEBkj (ORCPT ); Wed, 4 Mar 2015 20:40:39 -0500 X-IronPort-AV: E=Sophos;i="5.04,848,1406563200"; d="scan'208";a="64263227" Message-ID: <54F7B006.9050203@cn.fujitsu.com> Date: Thu, 5 Mar 2015 09:23:18 +0800 From: Gu Zheng User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20110930 Thunderbird/7.0.1 MIME-Version: 1.0 To: Kamezawa Hiroyuki CC: Tejun Heo , , , , Subject: Re: [PATCH] workqueue: update numa affinity when node hotplug References: <1425031492-32300-1-git-send-email-guz.fnst@cn.fujitsu.com> <20150227115401.GD3964@htj.duckdns.org> <54F42221.6000904@jp.fujitsu.com> <20150302162854.GG17694@htj.duckdns.org> <54F55A7A.7060100@jp.fujitsu.com> <20150303131852.GA3122@htj.duckdns.org> <54F69C0B.6030502@jp.fujitsu.com> In-Reply-To: <54F69C0B.6030502@jp.fujitsu.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.167.226.100] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Kamazawa-san, On 03/04/2015 01:45 PM, Kamezawa Hiroyuki wrote: > On 2015/03/03 22:18, Tejun Heo wrote: >> Hello, Kame. >> >> On Tue, Mar 03, 2015 at 03:53:46PM +0900, Kamezawa Hiroyuki wrote: >>> relationship between proximity domain and lapic id doesn't change. >>> relationship between lapic-id and cpu-id changes. >>> >>> pxm <-> memory address : no change >>> pxm <-> lapicid : no change >>> pxm <-> node id : no change >>> lapicid <-> cpu id : change. >> >> So, we're changing the cpu ID to NUMA node mapping because current >> NUMA code is ignoring PXM for memoryless nodes? That's it? >> > > For memory-less node case, yes. > Another problem is that lapicid <-> cpuid relationship is not persistent. > > >>>>> I personally thinks proper fix is building persistent cpu-id <-> lapicid relationship as >>>>> pxm does rather than creating band-aid. >>>> >>>> Oh if this is possible, I agree that's the right direction too. >>>> >>> >>> Implementation is a bit complicated now :(. >> >> Ah well, even then, the obviously right thing to do is updating NUMA >> code to always keep track of PXM information. We don't really want to >> pile NUMA hacks in random users of NUMA code. >> > > We'd like to start from making apicid <-> cpuid persistent because memory-less > node case doesn't cause panic. > > Gu-san, how do you think ? Fine by me. But it seems that the change will break the re-use of free cpuid when hot add new cpus, I am afraid it may affect other sub-systems, though I can not point out the specific example. Thanks, Gu > > Thanks, > -Kame > > P.S. > Finally, I want something like udev for cpuid/numaid... > > > . >