Re: [PATCH v37 0/3] Virtio-balloon: support free page reporting

[Wei Wang]

On 10/25/2018 08:58 AM, Michael S. Tsirkin wrote:
> On Mon, Aug 27, 2018 at 09:32:16AM +0800, Wei Wang wrote:
> > The new feature, VIRTIO_BALLOON_F_FREE_PAGE_HINT, implemented by this
> > series enables the virtio-balloon driver to report hints of guest free
> > pages to host. It can be used to accelerate virtual machine (VM) live
> > migration. Here is an introduction of this usage:
> >
> > Live migration needs to transfer the VM's memory from the source machine
> > to the destination round by round. For the 1st round, all the VM's memory
> > is transferred. From the 2nd round, only the pieces of memory that were
> > written by the guest (after the 1st round) are transferred. One method
> > that is popularly used by the hypervisor to track which part of memory is
> > written is to have the hypervisor write-protect all the guest memory.
> >
> > This feature enables the optimization by skipping the transfer of guest
> > free pages during VM live migration. It is not concerned that the memory
> > pages are used after they are given to the hypervisor as a hint of the
> > free pages, because they will be tracked by the hypervisor and transferred
> > in the subsequent round if they are used and written.
> OK so it will be in linux-next.  Now can I trouble you for a virtio spec
> patch with the description please?

No problem, I'll start to patch the spec. Thanks!

Best,
Wei