On Mon, Apr 28, 2025 at 05:39:46PM +0200, Cédric Le Goater wrote:
> On 4/9/25 15:48, John Levon wrote:
> > Instead of requesting region information on demand with
> > VFIO_DEVICE_GET_REGION_INFO, maintain a cache: this will become
> > necessary for performance for vfio-user, where this call becomes a
> > message over the control socket, so is of higher overhead than the
> > traditional path.
>
> > +static void vfio_device_get_all_region_info(VFIODevice *vbasedev)
> > +{
> > + struct vfio_region_info *info;
> > + int i;
> > +
> > + for (i = 0; i < vbasedev->num_regions; i++) {
> > + vfio_device_get_region_info(vbasedev, i, &info);
> > + }
> > +}
> > +
>
> if the vfio_device_get_all_region_info() routine queries *all* region
> infos to fill the ->reginfo[] cache array, why do we also need the
> lazy cache filling method in vfio_device_get_region_info() ? This looks
> redundant to me. I would rather have vfio_device_get_region_info()
> operate on the cache only.
I think we briefly talked about this last time. I don't know why the cache fill
code is there; I can drop it.
regards
john
