From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: soft lockup after stop/cont Date: Wed, 10 Oct 2007 11:18:35 +0200 Message-ID: <470C98EB.1080602@qumranet.com> References: <20071010080152.GA27601@jim.sh> <470C87AB.6050900@qumranet.com> <10EA09EFD8728347A513008B6B0DA77A023643BD@pdsmsx411.ccr.corp.intel.com> <470C96B2.3080905@qumranet.com> <10EA09EFD8728347A513008B6B0DA77A02364404@pdsmsx411.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: "Dong, Eddie" Return-path: In-Reply-To: <10EA09EFD8728347A513008B6B0DA77A02364404-wq7ZOvIWXbNpB2pF5aRoyrfspsVTdybXVpNB7YpNyf8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Dong, Eddie wrote: > Avi Kivity wrote: > >> Dong, Eddie wrote: >> >>> kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org wrote: >>> >>> >>>> It may be that the timer correction code detects that zillions of >>>> timer interrupts have not been serviced by the guest so it floods >>>> the guest with these interrupts. Does -no-kvm-irqchip help? >>>> >>>> >>>> >>> In Xen, we decide to froze the guest time after save/restore. In this >>> way the guest see contiguous timer and thus avoid this issue. >>> >>> Probably we should do similar here, comments? >>> >>> >> This is pause/resume, not save/restore. I think save/restore now has >> contiguous lapic timer and discontiguous real time. >> >> > > If save/restore means live migration here, yes you are right. > No, I didn't mean that. > save to file and later resume from file will have this issue. > Why? after saving to a file, the local apic in the kernel is destroyed when qemu quits. Or is the timer saved in absolute time? if so you are right, and yes, your solution is needed. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/