From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754452Ab3GJLbg (ORCPT ); Wed, 10 Jul 2013 07:31:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54525 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753735Ab3GJLbe (ORCPT ); Wed, 10 Jul 2013 07:31:34 -0400 Date: Wed, 10 Jul 2013 14:29:24 +0300 From: Gleb Natapov To: Raghavendra K T Cc: Peter Zijlstra , Andrew Jones , mingo@redhat.com, ouyang@cs.pitt.edu, habanero@linux.vnet.ibm.com, jeremy@goop.org, x86@kernel.org, konrad.wilk@oracle.com, hpa@zytor.com, pbonzini@redhat.com, linux-doc@vger.kernel.org, xen-devel@lists.xensource.com, mtosatti@redhat.com, stefano.stabellini@eu.citrix.com, andi@firstfloor.org, attilio.rao@citrix.com, gregkh@suse.de, agraf@suse.de, chegu_vinod@hp.com, torvalds@linux-foundation.org, avi.kivity@gmail.com, tglx@linutronix.de, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, stephan.diestelhorst@amd.com, riel@redhat.com, virtualization@lists.linux-foundation.org, srivatsa.vaddagiri@gmail.com Subject: Re: [PATCH RFC V9 0/19] Paravirtualized ticket spinlocks Message-ID: <20130710112924.GT24941@redhat.com> References: <20130626113744.GA6300@hawk.usersys.redhat.com> <20130626125240.GY18508@redhat.com> <51CAEF45.3010203@linux.vnet.ibm.com> <20130626161130.GB18152@redhat.com> <51CB2AD9.5060508@linux.vnet.ibm.com> <51DBD3C2.2040807@linux.vnet.ibm.com> <20130710103325.GP24941@redhat.com> <20130710104047.GP25631@dyad.programming.kicks-ass.net> <20130710104717.GR24941@redhat.com> <51DD455D.4000701@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51DD455D.4000701@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 10, 2013 at 04:58:29PM +0530, Raghavendra K T wrote: > On 07/10/2013 04:17 PM, Gleb Natapov wrote: > >On Wed, Jul 10, 2013 at 12:40:47PM +0200, Peter Zijlstra wrote: > >>On Wed, Jul 10, 2013 at 01:33:25PM +0300, Gleb Natapov wrote: > >> > >>Here's an idea, trim the damn email ;-) -- not only directed at gleb. > >> > >Good idea. > > > >>>>Ingo, Gleb, > >>>> > >>>> From the results perspective, Andrew Theurer, Vinod's test results are > >>>>pro-pvspinlock. > >>>>Could you please help me to know what will make it a mergeable > >>>>candidate?. > >>>> > >>>I need to spend more time reviewing it :) The problem with PV interfaces > >>>is that they are easy to add but hard to get rid of if better solution > >>>(HW or otherwise) appears. > >> > >>How so? Just make sure the registration for the PV interface is optional; that > >>is, allow it to fail. A guest that fails the PV setup will either have to try > >>another PV interface or fall back to 'native'. > >> > >We have to carry PV around for live migration purposes. PV interface > >cannot disappear under a running guest. > > > > IIRC, The only requirement was running state of the vcpu to be retained. > This was addressed by > [PATCH RFC V10 13/18] kvm : Fold pv_unhalt flag into GET_MP_STATE > ioctl to aid migration. > > I would have to know more if I missed something here. > I was not talking about the state that has to be migrated, but HV<->guest interface that has to be preserved after migration. -- Gleb. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH RFC V9 0/19] Paravirtualized ticket spinlocks Date: Wed, 10 Jul 2013 14:29:24 +0300 Message-ID: <20130710112924.GT24941@redhat.com> References: <20130626113744.GA6300@hawk.usersys.redhat.com> <20130626125240.GY18508@redhat.com> <51CAEF45.3010203@linux.vnet.ibm.com> <20130626161130.GB18152@redhat.com> <51CB2AD9.5060508@linux.vnet.ibm.com> <51DBD3C2.2040807@linux.vnet.ibm.com> <20130710103325.GP24941@redhat.com> <20130710104047.GP25631@dyad.programming.kicks-ass.net> <20130710104717.GR24941@redhat.com> <51DD455D.4000701@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: jeremy@goop.org, gregkh@suse.de, kvm@vger.kernel.org, linux-doc@vger.kernel.org, Peter Zijlstra , riel@redhat.com, virtualization@lists.linux-foundation.org, andi@firstfloor.org, hpa@zytor.com, stefano.stabellini@eu.citrix.com, xen-devel@lists.xensource.com, x86@kernel.org, mingo@redhat.com, habanero@linux.vnet.ibm.com, Andrew Jones , konrad.wilk@oracle.com, ouyang@cs.pitt.edu, avi.kivity@gmail.com, tglx@linutronix.de, chegu_vinod@hp.com, linux-kernel@vger.kernel.org, srivatsa.vaddagiri@gmail.com, attilio.rao@citrix.com, pbonzini@redhat.com, torvalds@linux-foundation.org, stephan.diestelhorst@amd.com To: Raghavendra K T Return-path: Content-Disposition: inline In-Reply-To: <51DD455D.4000701@linux.vnet.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Id: kvm.vger.kernel.org On Wed, Jul 10, 2013 at 04:58:29PM +0530, Raghavendra K T wrote: > On 07/10/2013 04:17 PM, Gleb Natapov wrote: > >On Wed, Jul 10, 2013 at 12:40:47PM +0200, Peter Zijlstra wrote: > >>On Wed, Jul 10, 2013 at 01:33:25PM +0300, Gleb Natapov wrote: > >> > >>Here's an idea, trim the damn email ;-) -- not only directed at gleb. > >> > >Good idea. > > > >>>>Ingo, Gleb, > >>>> > >>>> From the results perspective, Andrew Theurer, Vinod's test results are > >>>>pro-pvspinlock. > >>>>Could you please help me to know what will make it a mergeable > >>>>candidate?. > >>>> > >>>I need to spend more time reviewing it :) The problem with PV interfaces > >>>is that they are easy to add but hard to get rid of if better solution > >>>(HW or otherwise) appears. > >> > >>How so? Just make sure the registration for the PV interface is optional; that > >>is, allow it to fail. A guest that fails the PV setup will either have to try > >>another PV interface or fall back to 'native'. > >> > >We have to carry PV around for live migration purposes. PV interface > >cannot disappear under a running guest. > > > > IIRC, The only requirement was running state of the vcpu to be retained. > This was addressed by > [PATCH RFC V10 13/18] kvm : Fold pv_unhalt flag into GET_MP_STATE > ioctl to aid migration. > > I would have to know more if I missed something here. > I was not talking about the state that has to be migrated, but HV<->guest interface that has to be preserved after migration. -- Gleb.