From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758703AbZCAXiu (ORCPT ); Sun, 1 Mar 2009 18:38:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756557AbZCAXil (ORCPT ); Sun, 1 Mar 2009 18:38:41 -0500 Received: from gw.goop.org ([64.81.55.164]:36131 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756351AbZCAXil (ORCPT ); Sun, 1 Mar 2009 18:38:41 -0500 Message-ID: <49AB1C7D.2040605@goop.org> Date: Sun, 01 Mar 2009 15:38:37 -0800 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.19 (X11/20090105) MIME-Version: 1.0 To: Andi Kleen CC: Jody Belka , Nick Piggin , Xen-devel , the arch/x86 maintainers , Linux Kernel Mailing List , "H. Peter Anvin" , Andrew Morton Subject: Re: [PATCH] xen: core dom0 support References: <1235786365-17744-1-git-send-email-jeremy@goop.org> <20090227212812.26d02f34.akpm@linux-foundation.org> <49A8DF28.4050301@goop.org> <200902282309.07576.nickpiggin@yahoo.com.au> <20090228181115.GU2056@pimb.org> <871vti2zsl.fsf@basil.nowhere.org> In-Reply-To: <871vti2zsl.fsf@basil.nowhere.org> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andi Kleen wrote: > Jody Belka writes: > >> Is it duplication though? I personally have machines with older processors >> that don't have hvm support. I plan on keeping these around for a good amount >> of time, and would love to be running them on mainline. So for me, unless KVM >> is somehow going to support para-virtualisation, this isn't duplication. >> > > The old systems will continue to run fine with a 2.6.18 Dom0 though. But that suggests the *only* reason to update kernels is to get new hardware support. Or conversely, we should stop trying to be backwards compatible with old hardware in new kernels because there's no reason to keep it. While a lot of the delta between 2.6.18 has been hardware support updates, there have been a lot of other useful things: a new CPU scheduler, tickless operation (which directly important for virtualization), all the cgroups stuff, new filesystems, IO schedulers, etc, etc. All good things to have, even on older hardware. J From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: [PATCH] xen: core dom0 support Date: Sun, 01 Mar 2009 15:38:37 -0800 Message-ID: <49AB1C7D.2040605@goop.org> References: <1235786365-17744-1-git-send-email-jeremy@goop.org> <20090227212812.26d02f34.akpm@linux-foundation.org> <49A8DF28.4050301@goop.org> <200902282309.07576.nickpiggin@yahoo.com.au> <20090228181115.GU2056@pimb.org> <871vti2zsl.fsf@basil.nowhere.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <871vti2zsl.fsf@basil.nowhere.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Andi Kleen Cc: Nick Piggin , Xen-devel , the arch/x86 maintainers , Linux Kernel Mailing List , "H. Peter Anvin" , Andrew Morton List-Id: xen-devel@lists.xenproject.org Andi Kleen wrote: > Jody Belka writes: > >> Is it duplication though? I personally have machines with older processors >> that don't have hvm support. I plan on keeping these around for a good amount >> of time, and would love to be running them on mainline. So for me, unless KVM >> is somehow going to support para-virtualisation, this isn't duplication. >> > > The old systems will continue to run fine with a 2.6.18 Dom0 though. But that suggests the *only* reason to update kernels is to get new hardware support. Or conversely, we should stop trying to be backwards compatible with old hardware in new kernels because there's no reason to keep it. While a lot of the delta between 2.6.18 has been hardware support updates, there have been a lot of other useful things: a new CPU scheduler, tickless operation (which directly important for virtualization), all the cgroups stuff, new filesystems, IO schedulers, etc, etc. All good things to have, even on older hardware. J