Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751601Ab2JWC4W (ORCPT ); Mon, 22 Oct 2012 22:56:22 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:35468 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1750822Ab2JWC4V (ORCPT ); Mon, 22 Oct 2012 22:56:21 -0400 X-IronPort-AV: E=Sophos;i="4.80,634,1344182400"; d="scan'208";a="6048008" Message-ID: <50860711.10807@cn.fujitsu.com> Date: Tue, 23 Oct 2012 10:55:13 +0800 From: Tang Chen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Borislav Petkov , Borislav Petkov , tony.luck@intel.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, miaox@cn.fujitsu.com, laijs@cn.fujitsu.com, wency@cn.fujitsu.com, x86@kernel.org, linux-edac@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] Replace if statement with WARN_ON_ONCE() in cmci_rediscover(). References: <1350625528-1385-1-git-send-email-tangchen@cn.fujitsu.com> <1350625528-1385-2-git-send-email-tangchen@cn.fujitsu.com> <20121019164045.GE11958@aftab.osrc.amd.com> <5084AB10.7010807@cn.fujitsu.com> <20121022101442.GB8352@liondog.tnic> In-Reply-To: <20121022101442.GB8352@liondog.tnic> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/23 10:55:46, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/23 10:55:48, Serialize complete at 2012/10/23 10:55:48 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 991 Lines: 31 On 10/22/2012 06:14 PM, Borislav Petkov wrote: > On Mon, Oct 22, 2012 at 10:10:24AM +0800, Tang Chen wrote: >> I don't why before we just jumped over it. But I think if we have an >> online cpu == dying here, it must be wrong. So I think we should warn >> it, not just jump over it. > > Why do we need to warn? What good would that bring us? > > AFAICT, the check in cmci_rediscover is there to make sure we absolutely > don't rediscover on the dying cpu. I think it is a safety precaution in > concurrency scenarios between cpu hotplug and mce code. Well, I see. I dropped the if statement. :) So, how about warn once, and continue: if (cpu == dying) { WARN_ON_ONCE(cpu == dying); continue; } or, use BUG_ON() instead ? > > Thanks. > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/