Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758934AbXKGXRi (ORCPT ); Wed, 7 Nov 2007 18:17:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755066AbXKGXRb (ORCPT ); Wed, 7 Nov 2007 18:17:31 -0500 Received: from mail.suse.de ([195.135.220.2]:59083 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754841AbXKGXRa (ORCPT ); Wed, 7 Nov 2007 18:17:30 -0500 From: Andi Kleen To: Andrew Morton Subject: Re: is minimum udelay() not respected in preemptible SMP kernel-2.6.23? Date: Thu, 8 Nov 2007 00:10:44 +0100 User-Agent: KMail/1.9.1 Cc: Marin Mitov , linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar References: <200711071921.52330.mitov@issp.bas.bg> <20071107123045.c6d4b855.akpm@linux-foundation.org> In-Reply-To: <20071107123045.c6d4b855.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200711080010.44632.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 553 Lines: 15 > Ow. Yes, from my reading delay_tsc() can return early (or after > heat-death-of-the-universe) if the TSCs are offset and if preemption > migrates the calling task between CPUs. > > I suppose a lameo fix would be to disable preemption in delay_tsc(). Yes. Can't think of any better reasonable fix. -Andi - 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/