From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753339Ab2LXRwX (ORCPT ); Mon, 24 Dec 2012 12:52:23 -0500 Received: from mail-pa0-f49.google.com ([209.85.220.49]:36213 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753183Ab2LXRwU (ORCPT ); Mon, 24 Dec 2012 12:52:20 -0500 Date: Mon, 24 Dec 2012 09:55:32 -0800 From: Greg KH To: "he, bo" Cc: Randy Dunlap , akpm@linux-foundation.org, mingo@elte.hu, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, yanmin_zhang@linux.intel.com Subject: Re: [PATCH V2] output the cpu number when printking. Message-ID: <20121224175532.GA15041@kroah.com> References: <1356316276.2385.7.camel@hebo> <50D7CDED.4060308@infradead.org> <1356321255.2385.8.camel@hebo> <1356325315.2385.74.camel@hebo> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1356325315.2385.74.camel@hebo> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 24, 2012 at 01:01:55PM +0800, he, bo wrote: > From: "he, bo" > > We often hit kernel panic issues on SMP machines because processes race > on multiple cpu. By adding a new parameter printk.cpu, kernel prints > cpu number at printk information line. It’s useful to debug what cpus > are racing. How useful is this really for normal developers? We complained when this option was proposed by the ARM developers who were, for the first time, handling more than one processor and the issues involved with that. You are enabling this as a default option, for all developers, and almost no one will ever need it. So, if you really want this, don't enable this by default. Also, go back and read the old thread about this option and why it was rejeted previously. thanks, greg k-h