From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755089Ab3BDOCP (ORCPT ); Mon, 4 Feb 2013 09:02:15 -0500 Received: from mail.skyhub.de ([78.46.96.112]:53385 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754315Ab3BDOCO (ORCPT ); Mon, 4 Feb 2013 09:02:14 -0500 Date: Mon, 4 Feb 2013 15:02:03 +0100 From: Borislav Petkov To: Rik van Riel Cc: Ingo Molnar , linux-kernel@vger.kernel.org, aquini@redhat.com, walken@google.com, eric.dumazet@gmail.com, lwoodman@redhat.com, knoel@redhat.com, chegu_vinod@hp.com, raghavendra.kt@linux.vnet.ibm.com, mingo@redhat.com Subject: Re: [PATCH -v4 5/5] x86,smp: limit spinlock delay on virtual machines Message-ID: <20130204140203.GB15452@pd.tnic> Mail-Followup-To: Borislav Petkov , Rik van Riel , Ingo Molnar , linux-kernel@vger.kernel.org, aquini@redhat.com, walken@google.com, eric.dumazet@gmail.com, lwoodman@redhat.com, knoel@redhat.com, chegu_vinod@hp.com, raghavendra.kt@linux.vnet.ibm.com, mingo@redhat.com References: <20130125140553.060b8ced@annuminas.surriel.com> <20130125141917.6d5960a8@annuminas.surriel.com> <20130126120043.GB13445@gmail.com> <20130126124716.GB21395@pd.tnic> <510FBCA9.4070700@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <510FBCA9.4070700@redhat.com> 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, Feb 04, 2013 at 08:50:33AM -0500, Rik van Riel wrote: > We need to know whether we are actually running on top of a > hypervisor, not whether we have the code compiled in to do so. Oh ok, I see. The thing is, if CONFIG_PARAVIRT_GUEST is disabled, x86_hyper won't exist, see: http://marc.info/?l=linux-kernel&m=135936817627848&w=2 So maybe the hypervisor guest should itself take care of this and upon init it should set the max_spinlock_delay in init_hypervisor() instead? Seems only fair to me... > After all, the majority of distribution kernels will have > CONFIG_PARAVIRT_GUEST set, but the majority of those kernels > will be running bare metal... Yeah :-) Thanks. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --