Re: [virtio-dev] Dirty Page Tracking (DPT)

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Apr 07, 2020 at 11:52:46AM +0200, Eugenio Perez Martin wrote:
> Hi!
> 
> So, from the previous mails, it seems that monitoring the used ring
> (and the packed descriptors) is a good first step in that direction,
> as DPDK did. This way, the device does not need to worry about the
> dirty page tracking using a bitmap and the PCI writes limitation, and
> we can evaluate later the proposed alternatives:
> * Alternate used descriptors in packed.
> * vDPA interface for vDPA devices in a convenient format.
> 
> Any thoughts? Do you think that we should start with another way?
> 
> Thanks!

I am concerned that with software in data path, we'll hit RX queue
underruns, won't we?
Two ways to avoid underruns:
- dirty page tracking
- page faults

I'm working on a proposal for page faults now. If someone wants
to work on dirty tracking in addition, that's also an option.

-- 
MST