From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755955Ab2IZIwR (ORCPT ); Wed, 26 Sep 2012 04:52:17 -0400 Received: from e23smtp02.au.ibm.com ([202.81.31.144]:47198 "EHLO e23smtp02.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755860Ab2IZIwP (ORCPT ); Wed, 26 Sep 2012 04:52:15 -0400 Message-ID: <5062C215.8030602@linux.vnet.ibm.com> Date: Wed, 26 Sep 2012 14:21:33 +0530 From: "Srivatsa S. Bhat" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120828 Thunderbird/15.0 MIME-Version: 1.0 To: "Liu, Chuansheng" CC: "tglx@linutronix.de" , "mingo@redhat.com" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , "yanmin_zhang@linux.intel.com" , Ingo Molnar Subject: Re: [PATCH] x86/fixup_irq: Clean the offlining CPU from the irq affinity mask References: <1348669924.19514.6.camel@cliu38-desktop-build> <5062A442.2030207@linux.vnet.ibm.com> <27240C0AC20F114CBF8149A2696CBE4A189F97@SHSMSX101.ccr.corp.intel.com> <5062B602.6000502@linux.vnet.ibm.com> <27240C0AC20F114CBF8149A2696CBE4A18A27F@SHSMSX101.ccr.corp.intel.com> In-Reply-To: <27240C0AC20F114CBF8149A2696CBE4A18A27F@SHSMSX101.ccr.corp.intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit x-cbid: 12092608-5490-0000-0000-000002325168 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/26/2012 01:40 PM, Liu, Chuansheng wrote: >> Btw, on a slightly different note, I'm also rather surprised that the above >> code doesn't care about the return value of chip->irq_set_affinity() .. >> Shouldn't we warn if that fails? > > It seems another case when irq_set_affinity is NULL whenever affinity is changed or not before that, > For this case, I suppose the chip is not supporting set_affinity, then the chip should set all > related irqs into just CPU0, otherwise, it will bring some trouble, do you agree? > Hmm.. no, I wouldn't jump to do that. Moreover, note that there are patches in -tip to enable CPU 0 hotplug. So doing the above might not be terribly helpful going forward. > I guess this case should be covered outside fixup_irqs() code. > Regards, Srivatsa S. Bhat