Re: [PATCH v16 5/5] virtio-balloon: VIRTIO_BALLOON_F_CTRL_VQ

[Wei Wang <wei.w.wang@intel.com>]

On 10/13/2017 09:38 PM, Michael S. Tsirkin wrote:
> On Thu, Oct 12, 2017 at 11:54:56AM +0800, Wei Wang wrote:
> > > But I think flushing is very fragile. You will easily run into races
> > > if one of the actors gets out of sync and keeps adding data.
> > > I think adding an ID in the free vq stream is a more robust
> > > approach.
> > Adding ID to the free vq would need the device to distinguish whether it
> > receives an ID or a free page hint,
> Not really.  It's pretty simple: a 64 bit buffer is an ID. A 4K and bigger one
> is a page.

I think we can also use the previous method, free page via in_buf, and 
id via out_buf.

Best,
Wei