Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756089AbYHQR3a (ORCPT ); Sun, 17 Aug 2008 13:29:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753450AbYHQR3T (ORCPT ); Sun, 17 Aug 2008 13:29:19 -0400 Received: from mtagate1.de.ibm.com ([195.212.29.150]:50043 "EHLO mtagate1.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752653AbYHQR3S (ORCPT ); Sun, 17 Aug 2008 13:29:18 -0400 Subject: Re: [patch 1/3] kmsg: Kernel message catalog macros. From: Martin Schwidefsky Reply-To: schwidefsky@de.ibm.com To: Tim Hockin Cc: Rusty Russell , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, lf_kernel_messages@lists.linux-foundation.org, Andrew Morton , Michael Holzheu , Gerrit Huizenga , Greg Kroah-Hartman , Randy Dunlap , Jan Kara , Pavel Machek , Sam Ravnborg , Joe Perches , Jochen =?ISO-8859-1?Q?Vo=DF?= , Kunai Takashi , Tim Bird In-Reply-To: References: <20080730165656.118280544@de.ibm.com> <200808131433.02966.rusty@rustcorp.com.au> <1218733623.2651.14.camel@localhost> <200808150922.23277.rusty@rustcorp.com.au> <1218908985.6037.12.camel@localhost> Content-Type: text/plain Organization: IBM Corporation Date: Sun, 17 Aug 2008 19:28:58 +0200 Message-Id: <1218994138.20098.6.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1275 Lines: 31 On Sat, 2008-08-16 at 13:40 -0700, Tim Hockin wrote: > >> > > Can you hash the format string to generate the id? 6 hex digits should > >> > > be enough, and your tool can check for clashes. As it's bad form to have > >> > > identical strings for different semantics anyway, this seems to make > >> > > sense. > > > Ok, so a specialized version of printk will do the work to calculate > > the hash. Only, what will we do if there ever is a conflict? The message > > tag has to be unique. The shorter the hash is, the more likely a > > collision gets. Don't know if 6 hash digits is enough to just ignore the > > problem. > > And if you ever need to change the text that is in the format string? > The hash changes. That seems exactly counter to your goal... The only problem here is trivial change like typos. Then the hash changes although the message is semantically still the same. If the message really changes, its id should change as well. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin. -- 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/