From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Zhai, Edwin" Subject: Re: [PATCH] [IOEMU]: fix the crash of HVM live migration with intensive disk access Date: Tue, 01 Sep 2009 08:40:23 +0800 Message-ID: <4A9C6D77.2070107@intel.com> References: <20090811121251.GA16082@edwin-srv.sh.intel.com> <4A823278.6050207@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4A823278.6050207@intel.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Gianluca.Guida@eu.citrix.com Cc: "xen-devel@lists.xensource.com" , Ian Jackson , "Zhai, Edwin" , Stefano Stabellini List-Id: xen-devel@lists.xenproject.org Gianluca, Do you have comments for this? Maybe Stefano and I are on the same page. My assumption is that we need keep the cpu_physical_memory_set_dirty and phys_ram_dirty for qemu itself, and make cpu_physical_memory_set_dirty call xc_hvm_modified_memory if in live migration. Thanks, Zhai, Edwin wrote: > > > Stefano Stabellini wrote: >> On Tue, 11 Aug 2009, Zhai, Edwin wrote: >> >>> [IOEMU]: fix the crash of HVM live migration with intensive disk >>> access >>> >>> Intensive disk access, e.g. sum of big file, during HVM live >>> migration would cause guest error even file system crash. Guest >>> dmesg said >>> "attempt to access beyond end of device >>> hda1: rw=0, want=10232032112, limit=10474317" >>> >>> Current map cache used by qemu dma doesn't mark the page dirty, so >>> that these pages(probably holding DMA data struct) are not >>> transferred in the last iteration during live migration. >>> >>> This patch fixes it, and also merges the qemu's original dirty >>> bitmap used by other devices such as vga. >>> >>> Signed-Off-By: Zhai Edwin >>> >>> >> >> I think the fix is correct but we should thinking about dropping >> logdirty and start using xc_hvm_modified_memory instead for all cases. >> > > One interface should be better. But I'm not sure about the perf > implications. You know, qemu use logdirty for its device emulation > even without live migration, e.g. vga screen refresh. Changing to > xc_hvm_modified_memory would cause many hypercall to set/get the > bitmap in xen... > >> I think Gianluca also may have something to say about this but this week >> he is on vacation. >> >> > -- best rgds, edwin