Re: [PATCH V2 6/6] virtio-pci: implement dirty page tracking

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

On Mon, Nov 06, 2023 at 11:07:24AM +0000, Parav Pandit wrote:
> 
> > From: Michael S. Tsirkin <mst@redhat.com>
> > Sent: Monday, November 6, 2023 4:36 PM
> > On Mon, Nov 06, 2023 at 10:52:46AM +0000, Parav Pandit wrote:
> > > I read the pci spec and I see only 3 operations which does not have atomic or.
> > 
> > CAS+retry can be used to implement any atomics including atomic or.
> 
> Yes, we considered it. the PCI backpressure is lot that negates the value of such retries for such small transactions.

if there's some locality device can buffer these up maybe,
though of course the chances of a failure increase then.