From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754310AbbCBQd2 (ORCPT ); Mon, 2 Mar 2015 11:33:28 -0500 Received: from mail.skyhub.de ([78.46.96.112]:43488 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753803AbbCBQd1 (ORCPT ); Mon, 2 Mar 2015 11:33:27 -0500 Date: Mon, 2 Mar 2015 17:32:16 +0100 From: Borislav Petkov To: Naoya Horiguchi Cc: Naoya Horiguchi , "Luck, Tony" , Prarit Bhargava , Vivek Goyal , "linux-kernel@vger.kernel.org" , Junichi Nomura , Kiyoshi Ueda Subject: Re: [PATCH v2 1/2] x86: mce: kexec: turn off MCE in kexec Message-ID: <20150302163216.GF17521@pd.tnic> References: <1425013116-23581-1-git-send-email-n-horiguchi@ah.jp.nec.com> <54F05080.9090605@redhat.com> <20150227120648.GA3337@pd.tnic> <3908561D78D1C84285E8C5FCA982C28F329F18A7@ORSMSX114.amr.corp.intel.com> <20150302023118.GB25064@hori1.linux.bs1.fc.nec.co.jp> <20150302121701.GA17521@pd.tnic> <54F474BD.1010802@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <54F474BD.1010802@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 02, 2015 at 11:33:33PM +0900, Naoya Horiguchi wrote: > Yes, CPU offlining is one option to keep other CPUs quiet. I'm not sure why > current kexec implementation doesn't offline the other CPUs but just doing > cpu_relax() loop, but my guess is that in some kernel panic situation (like > soft lockup) we want to keep CPUs' status undisturbed to make sure the bug's > info is captured in kdump. Well either offlining or keeping them in the idle loop is fine - they're not executing anything else and thus the probability of them causing an MCE becomes disappearingly small. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --