From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juergen Gross Subject: Re: xm save fails to save all pages Date: Tue, 25 Oct 2011 15:43:16 +0200 Message-ID: <4EA6BCF4.6090601@ts.fujitsu.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On 10/25/2011 03:32 PM, Keir Fraser wrote: > On 25/10/2011 14:15, "Juergen Gross" wrote: > >> in preparation to support live migration for BS2000 I'm testing my domU (HVM >> with PV-drivers) with xm save/restore. I'm running xen 4.0.2 (from SLES11 >> SP1). >> >> During xm save I see the following line in xend.log: >> >> [2011-10-25 13:25:25 31519] INFO (XendCheckpoint:484) Saving memory pages: >> iter 1 0%type fail: page 510 mfn 000011fe >> >> I added some diagnostic code to the hypervisor (in arch/x86/domctl.c) and >> found >> that the hypervisor believes gmfn 11fe of the domU is part of the xen heap. >> >> The problem is always reported for gmfn 11fe, regardless of the memory size of >> the domU: I tried 1, 2 and 8 GB. The memory page isn't used for anything >> special in the domU, there is no problem accessing it or mapping it to dom0 >> before doing the xm save (or after xm save -c). >> >> When I try to restore the saved domain I can't map gmfn 11fe of the domU any >> longer in dom0 (this was the first hint there is a problem at all). >> >> How can a domU memory page be part of the xen heap? > It could be the domain's shared-info page, or one of its grant-table pages. > It doesn't make sense to save/restore such pages -- they get reconstructed > appropriately on the receiving end, by the toolstack and/or by the domain > itself when it resumes execution. Thanks! It IS a grant-table page. Juergen -- Juergen Gross Principal Developer Operating Systems PDG ES&S SWE OS6 Telephone: +49 (0) 89 3222 2967 Fujitsu Technology Solutions e-mail: juergen.gross@ts.fujitsu.com Domagkstr. 28 Internet: ts.fujitsu.com D-80807 Muenchen Company details: ts.fujitsu.com/imprint.html