From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [RFC][PATCH] qemu-kvm: Introduce writeback scope for cpu_synchronize_state Date: Wed, 18 Nov 2009 15:46:50 +0200 Message-ID: <4B03FACA.3010500@redhat.com> References: <4B018542.3020602@siemens.com> <4B01A487.3020808@redhat.com> <4B01C2B0.3000205@web.de> <4B02592C.6060004@redhat.com> <4B025B50.4070505@web.de> <4B0260D7.1060107@redhat.com> <4B026A03.4080600@web.de> <4B0298F0.3080007@redhat.com> <4B029FA8.5080205@web.de> <4B02A4FD.4010802@redhat.com> <4B02AF58.4010407@web.de> <4B02B252.5080207@redhat.com> <4B02D444.6080402@web.de> <4B02D659.2040004@redhat.com> <4B03C348.4010604@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , kvm , Gleb Natapov To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:38338 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751534AbZKRNqr (ORCPT ); Wed, 18 Nov 2009 08:46:47 -0500 In-Reply-To: <4B03C348.4010604@web.de> Sender: kvm-owner@vger.kernel.org List-ID: On 11/18/2009 11:50 AM, Jan Kiszka wrote: > >> INIT, too. >> > INIT should be handled by queuing up the next mp_state. > And clearing the previous queue; otherwise our queue is unbounded. > BTW, as we do not inject mp_state changes from user space during > runtime, the issue I saw with the current interface is not existing. We > just need to add that queuing feature to asynchronous in-kernel mp_state > changes, and we should be fine. > > > Let's assume we will have such changes in future kernels: should > qemu-kvm and qemu upstream also bother about older kernels and establish > workarounds? Because then we need to find a cleaner approach than the > current one, and my proposed patch comes into the game again. > If we treat this as a bug, then we fix the older kernels too. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.