Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266871AbUIORGl (ORCPT ); Wed, 15 Sep 2004 13:06:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266674AbUIOREi (ORCPT ); Wed, 15 Sep 2004 13:04:38 -0400 Received: from convulsion.choralone.org ([212.13.208.157]:39178 "EHLO convulsion.choralone.org") by vger.kernel.org with ESMTP id S266646AbUIORAT (ORCPT ); Wed, 15 Sep 2004 13:00:19 -0400 Date: Wed, 15 Sep 2004 17:59:33 +0100 From: Dave Jones To: Lee Revell Cc: Jeff Garzik , Ricky Beam , Zilvinas Valinskas , Erik Tews , linux-kernel mailing list Subject: Re: 2.6.9 rc2 freezing Message-ID: <20040915165933.GD24892@redhat.com> Mail-Followup-To: Dave Jones , Lee Revell , Jeff Garzik , Ricky Beam , Zilvinas Valinskas , Erik Tews , linux-kernel mailing list References: <1095263296.2406.141.camel@krustophenia.net> <41486691.3080202@pobox.com> <1095264408.2406.148.camel@krustophenia.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1095264408.2406.148.camel@krustophenia.net> User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 721 Lines: 19 On Wed, Sep 15, 2004 at 12:06:48PM -0400, Lee Revell wrote: > Anyway, if you are running anything on your server that breaks under > PREEMPT, it will break anyway as soon as you add another processor. Wrong. Code can be SMP safe but not preempt safe. This is why we have get_cpu()/put_cpu(), and preempt_disable()/preempt_enable() pairs around certain parts of code. Anything using per-CPU data like MSRs for example needs explicit protection against preemption. Dave - 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/