From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423330AbXBPGP3 (ORCPT ); Fri, 16 Feb 2007 01:15:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1423331AbXBPGP3 (ORCPT ); Fri, 16 Feb 2007 01:15:29 -0500 Received: from smtp-outbound-1.vmware.com ([65.113.40.141]:48426 "EHLO smtp-outbound-1.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423330AbXBPGP2 (ORCPT ); Fri, 16 Feb 2007 01:15:28 -0500 Message-ID: <45D54BFF.80100@vmware.com> Date: Thu, 15 Feb 2007 22:15:27 -0800 From: Zachary Amsden User-Agent: Thunderbird 1.5.0.9 (X11/20061206) MIME-Version: 1.0 To: Jeremy Fitzhardinge CC: Andi Kleen , Andrew Morton , linux-kernel@vger.kernel.org, virtualization@lists.osdl.org, xen-devel@lists.xensource.com, Chris Wright , Ian Pratt , Christian Limpach , Avi Kivity , "Eric W. Biederman" Subject: Re: [patch 14/21] Xen-paravirt: Add XEN config options and disable unsupported config options. References: <20070216022449.739760547@goop.org> <20070216022531.570154735@goop.org> In-Reply-To: <20070216022531.570154735@goop.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jeremy Fitzhardinge wrote: > The XEN config option enables the Xen paravirt_ops interface, which is > installed when the kernel finds itself running under Xen. (By some > as-yet fully defined mechanism, implemented in a future patch.) > > Xen is no longer a sub-architecture, so the X86_XEN subarch config > option has gone. > > The disabled config options are: > - PREEMPT: Xen doesn't support it > - HZ: set to 100Hz for now, to cut down on VCPU context switch rate. > This will be adapted to use tickless later. > - kexec: not yet supported > > Signed-off-by: Jeremy Fitzhardinge > Signed-off-by: Ian Pratt > Signed-off-by: Christian Limpach > Signed-off-by: Chris Wright > We do support different HZ values, although 100HZ is actually preferable for us, so I don't object to that. PREEMPT is supported by us, but not as tested as I would like, so I also don't object to dropping it for generic paravirt guests - Rusty - Avi any objections to dropping preempt in terms of lguest/KVM paravirtualization? Paravirt-ops definitely needs a hook for kexec, although we should not disable kexec for the natively booted paravirt-ops. Eric - is there a way to disable it at runtime? We do support the doublefault task gate, and it would be good to keep it, but I can't complain so much if it is gone from generic paravirt kernels for now, because it is non-essential, and generally fatal anyway. We do need it for native boots of paravirt-ops kernels, however, so turning off the config option still needs to be revisited. Zach From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zachary Amsden Subject: Re: [patch 14/21] Xen-paravirt: Add XEN config options and disable unsupported config options. Date: Thu, 15 Feb 2007 22:15:27 -0800 Message-ID: <45D54BFF.80100@vmware.com> References: <20070216022449.739760547@goop.org> <20070216022531.570154735@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20070216022531.570154735@goop.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: Jeremy Fitzhardinge Cc: xen-devel@lists.xensource.com, Ian Pratt , virtualization@lists.osdl.org, linux-kernel@vger.kernel.org, Avi Kivity , Chris Wright , Andi Kleen , "Eric W. Biederman" , Andrew Morton , Christian Limpach List-Id: virtualization@lists.linuxfoundation.org Jeremy Fitzhardinge wrote: > The XEN config option enables the Xen paravirt_ops interface, which is > installed when the kernel finds itself running under Xen. (By some > as-yet fully defined mechanism, implemented in a future patch.) > > Xen is no longer a sub-architecture, so the X86_XEN subarch config > option has gone. > > The disabled config options are: > - PREEMPT: Xen doesn't support it > - HZ: set to 100Hz for now, to cut down on VCPU context switch rate. > This will be adapted to use tickless later. > - kexec: not yet supported > > Signed-off-by: Jeremy Fitzhardinge > Signed-off-by: Ian Pratt > Signed-off-by: Christian Limpach > Signed-off-by: Chris Wright > We do support different HZ values, although 100HZ is actually preferable for us, so I don't object to that. PREEMPT is supported by us, but not as tested as I would like, so I also don't object to dropping it for generic paravirt guests - Rusty - Avi any objections to dropping preempt in terms of lguest/KVM paravirtualization? Paravirt-ops definitely needs a hook for kexec, although we should not disable kexec for the natively booted paravirt-ops. Eric - is there a way to disable it at runtime? We do support the doublefault task gate, and it would be good to keep it, but I can't complain so much if it is gone from generic paravirt kernels for now, because it is non-essential, and generally fatal anyway. We do need it for native boots of paravirt-ops kernels, however, so turning off the config option still needs to be revisited. Zach