On Mon, Jan 29, 2018 at 04:20:57PM +0200, Gal Hammer wrote:
> The loading time of a VM is quite significant when its virtio
> devices use a large amount of virt-queues (e.g. a virtio-serial
> device with max_ports=511). Most of the time is spend in the
> creation of all the required event notifiers (ioeventfd and memory
> regions).
>
> This patch pack all the changes to the memory regions in a
> single memory transaction.
>
> Reported-by: Sitong Liu <address@hidden>
> Reported-by: Xiaoling Gao <address@hidden>
Just a small note: the way to hide the address is not to put it in:
Reported-by: Sitong Liu
Reported-by: Xiaoling Gao
a stub email isn't needed, it merely confuses tools.
I've fixed this up for now, no need to worry.
> Signed-off-by: Gal Hammer <gham...@redhat.com>
> ---
> hw/virtio/virtio.c | 22 ++++++++++++++++++++--
> 1 file changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 3667cd6..006d3d1 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -2572,8 +2572,9 @@ static Property virtio_properties[] = {
> static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev)
> {
> VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));
> - int n, r, err;
> + int i, n, r, err;
>
> + memory_region_transaction_begin();
> for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
> VirtQueue *vq = &vdev->vq[n];
> if (!virtio_queue_get_num(vdev, n)) {
> @@ -2596,9 +2597,11 @@ static int
> virtio_device_start_ioeventfd_impl(VirtIODevice *vdev)
> }
> event_notifier_set(&vq->host_notifier);
> }
> + memory_region_transaction_commit();
> return 0;
>
> assign_error:
> + i = n; /* save n for a second iteration after transaction is committed.
> */
> while (--n >= 0) {
> VirtQueue *vq = &vdev->vq[n];
> if (!virtio_queue_get_num(vdev, n)) {
> @@ -2608,7 +2611,14 @@ assign_error:
> event_notifier_set_handler(&vq->host_notifier, NULL);
> r = virtio_bus_set_host_notifier(qbus, n, false);
> assert(r >= 0);
> - virtio_bus_cleanup_host_notifier(qbus, n);
> + }
> + memory_region_transaction_commit();
> +
> + while (--i >= 0) {
> + if (!virtio_queue_get_num(vdev, i)) {
> + continue;
> + }
> + virtio_bus_cleanup_host_notifier(qbus, i);
> }
> return err;
> }
> @@ -2626,6 +2636,7 @@ static void
> virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev)
> VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));
> int n, r;
>
> + memory_region_transaction_begin();
> for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
> VirtQueue *vq = &vdev->vq[n];
>
> @@ -2635,6 +2646,13 @@ static void
> virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev)
> event_notifier_set_handler(&vq->host_notifier, NULL);
> r = virtio_bus_set_host_notifier(qbus, n, false);
> assert(r >= 0);
> + }
> + memory_region_transaction_commit();
> +
> + for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
> + if (!virtio_queue_get_num(vdev, n)) {
> + continue;
> + }
> virtio_bus_cleanup_host_notifier(qbus, n);
> }
> }
> --
> 2.7.5
