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Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's mem
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration |
Date: |
Fri, 27 Mar 2015 08:56:34 +0000 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Thu, Mar 26, 2015 at 11:29:43AM +0100, Juan Quintela wrote:
> Wen Congyang <address@hidden> wrote:
> > On 03/25/2015 05:50 PM, Juan Quintela wrote:
> >> zhanghailiang <address@hidden> wrote:
> >>> Hi all,
> >>>
> >>> We found that, sometimes, the content of VM's memory is
> >>> inconsistent between Source side and Destination side
> >>> when we check it just after finishing migration but before VM continue to
> >>> Run.
> >>>
> >>> We use a patch like bellow to find this issue, you can find it from affix,
> >>> and Steps to reprduce:
> >>>
> >>> (1) Compile QEMU:
> >>> ./configure --target-list=x86_64-softmmu --extra-ldflags="-lssl" && make
> >>>
> >>> (2) Command and output:
> >>> SRC: # x86_64-softmmu/qemu-system-x86_64 -enable-kvm -cpu
> >>> qemu64,-kvmclock -netdev tap,id=hn0-device
> >>> virtio-net-pci,id=net-pci0,netdev=hn0 -boot c -drive
> >>> file=/mnt/sdb/pure_IMG/sles/sles11_sp3.img,if=none,id=drive-virtio-disk0,cache=unsafe
> >>> -device
> >>> virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0
> >>> -vnc :7 -m 2048 -smp 2 -device piix3-usb-uhci -device usb-tablet
> >>> -monitor stdio
> >>
> >> Could you try to reproduce:
> >> - without vhost
> >> - without virtio-net
> >> - cache=unsafe is going to give you trouble, but trouble should only
> >> happen after migration of pages have finished.
> >
> > If I use ide disk, it doesn't happen.
> > Even if I use virtio-net with vhost=on, it still doesn't happen. I guess
> > it is because I migrate the guest when it is booting. The virtio net
> > device is not used in this case.
>
> Kevin, Stefan, Michael, any great idea?
You must use -drive cache=none if you want to use live migration. It
should not directly affect memory during migration though.
> >>> We have done further test and found that some pages has been
> >>> dirtied but its corresponding migration_bitmap is not set.
> >>> We can't figure out which modules of QEMU has missed setting bitmap
> >>> when dirty page of VM,
> >>> it is very difficult for us to trace all the actions of dirtying VM's
> >>> pages.
> >>
> >> This seems to point to a bug in one of the devices.
I think you'll need to track down which pages are different. If you are
lucky, their contents will reveal what the page is used for.
Stefan
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- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, (continued)
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, Li Zhijian, 2015/03/25
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, zhanghailiang, 2015/03/27
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, Dr. David Alan Gilbert, 2015/03/27
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, zhanghailiang, 2015/03/28
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, Dr. David Alan Gilbert, 2015/03/30
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, zhanghailiang, 2015/03/31
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, Juan Quintela, 2015/03/27
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, zhanghailiang, 2015/03/27
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, Juan Quintela, 2015/03/26
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, Michael S. Tsirkin, 2015/03/26
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration,
Stefan Hajnoczi <=
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, Wen Congyang, 2015/03/27
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, Stefan Hajnoczi, 2015/03/27
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, Wen Congyang, 2015/03/27
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, Stefan Hajnoczi, 2015/03/27
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, Juan Quintela, 2015/03/27
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, Juan Quintela, 2015/03/27
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, Wen Congyang, 2015/03/31
- Re: [Qemu-devel] [Migration Bug? ] Occasionally, the content of VM's memory is inconsistent between Source and Destination of migration, Stefan Hajnoczi, 2015/03/31