Re: [Qemu-devel] [PATCH v2] balloon: Fix failure of updating guest memory status

[Li, Liang Z]

> On Wed, Jul 06, 2016 at 10:36:33AM +0800, Liang Li wrote:
> > After live migration, 'guest-stats' can't get the expected memory
> > status in the guest. This issue is caused by commit 4eae2a657d.
> > The value of 's->stats_vq_elem' will be NULL after live migration, and
> > the check in the function 'balloon_stats_poll_cb()' will prevent the
> > 'virtio_notify()' from executing. So guest will not update the memory
> > status.
> >
> > Commit 4eae2a657d is doing the right thing, but 's->stats_vq_elem'
> > should be treated as part of balloon device state and migrated to
> > destination if it's not NULL to make everything works well.
> >
> > Signed-off-by: Liang Li <address@hidden>
> > Suggested-by: Paolo Bonzini <address@hidden>
> > Cc: Michael S. Tsirkin <address@hidden>
> > Cc: Ladi Prosek <address@hidden>
> > Cc: Paolo Bonzini <address@hidden>
> 
> I agree there's an issue but we don't change versions anymore.
> Breaking migrations for everyone is also not nice.
> 
> How about queueing virtio_balloon_receive_stats so it will get invoked when
> vm starts?
> 

Could you give more explanation about how it works?  I can't catch you.

Thanks!
Liang