Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423046AbXBHOn7 (ORCPT ); Thu, 8 Feb 2007 09:43:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1423076AbXBHOn7 (ORCPT ); Thu, 8 Feb 2007 09:43:59 -0500 Received: from nf-out-0910.google.com ([64.233.182.189]:7618 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423046AbXBHOn6 (ORCPT ); Thu, 8 Feb 2007 09:43:58 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=Oi6QLHHbl/wXsbD87qjqYKk31NwPp+ajixXAD12+6ecWZXa0un8LK2B6y06BJjEFml7dOFGlse8GmhC7mb6RkaY+B+LzpzcFoEN+RHMHJJeblxdK/z43ETxes8Wcz/HIiPDnVdoZtSEAYe3oez9Ma0gEqzo8INzH0fLMgzrAlPs= Message-ID: Date: Thu, 8 Feb 2007 09:43:56 -0500 From: "Dmitry Torokhov" To: "Rusty Russell" Subject: Re: [PATCH 9/11] Panic delay fix Cc: "Pavel Machek" , "Zachary Amsden" , "Andi Kleen" , "Linux Kernel Mailing List" , "Andrew Morton" , "Jeremy Fitzhardinge" , "Chris Wright" In-Reply-To: <1170880572.11736.4.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200702060353.l163rUmj000771@zach-dev.vmware.com> <20070206122729.GC47229@muc.de> <45C8FA2D.6010706@vmware.com> <20070207123552.GD4481@ucw.cz> <1170880572.11736.4.camel@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1216 Lines: 31 On 2/7/07, Rusty Russell wrote: > On Wed, 2007-02-07 at 12:35 +0000, Pavel Machek wrote: > > Ugh, it sounds like paravirt is more b0rken then I thought. It should > > always to the proper delay, then replace those udelays that are not > > needed on virtualized hardware with something else. > > > > Just magically defining udelay into nop is broken. > > We'd have to audit and figure out what udelays are for hardware and > which are not, but the evidence is that the vast majority of them are > for hardware and not needed for virtualization. > > Changing udelay to "hardware_udelay" or something all over the kernel > would have delayed the paravirt_ops merge by an infinite amount 8) > However I am not really fond of idea of adding constructs like this all over the code: #define USE_REAL_TIME_DELAY_I_REALLY_MEAN_IT_THIS_TIME_I_SWEAR as the time passes... Drivers should be blissfully ignorant of being run on virtual hardware. -- Dmitry - 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/