On Wed, Apr 5, 2023 at 7:38 PM Eugenio Perez Martin <epere...@redhat.com> wrote: > > Hi! > > As mentioned in the last upstream virtio-networking meeting, one of > the factors that adds more downtime to migration is the handling of > the guest memory (pin, map, etc). At this moment this handling is > bound to the virtio life cycle (DRIVER_OK, RESET). In that sense, the > destination device waits until all the guest memory / state is > migrated to start pinning all the memory. > > The proposal is to bind it to the char device life cycle (open vs > close), so all the guest memory can be pinned for all the guest / qemu > lifecycle. > > This has two main problems: > * At this moment the reset semantics forces the vdpa device to unmap > all the memory. So this change needs a vhost vdpa feature flag.
Is this true? I didn't find any codes to unmap the memory in vhost_vdpa_set_status(). Thanks > * This may increase the initialization time. Maybe we can delay it if > qemu is not the destination of a LM. Anyway I think this should be > done as an optimization on top. > > Any ideas or comments in this regard? > > Thanks! >
