On Fri, Mar 5, 2021 at 11:05 AM Jason Wang <jasowang@xxxxxxxxxx> wrote: > > > On 2021/3/4 4:58 下午, Yongji Xie wrote: > > On Thu, Mar 4, 2021 at 2:59 PM Jason Wang <jasowang@xxxxxxxxxx> wrote: > >> > >> On 2021/2/23 7:50 下午, Xie Yongji wrote: > >>> This patch introduces a workqueue to support injecting > >>> virtqueue's interrupt asynchronously. This is mainly > >>> for performance considerations which makes sure the push() > >>> and pop() for used vring can be asynchronous. > >> > >> Do you have pref numbers for this patch? > >> > > No, I can do some tests for it if needed. > > > > Another problem is the VIRTIO_RING_F_EVENT_IDX feature will be useless > > if we call irq callback in ioctl context. Something like: > > > > virtqueue_push(); > > virtio_notify(); > > ioctl() > > ------------------------------------------------- > > irq_cb() > > virtqueue_get_buf() > > > > The used vring is always empty each time we call virtqueue_push() in > > userspace. Not sure if it is what we expected. > > > I'm not sure I get the issue. > > THe used ring should be filled by virtqueue_push() which is done by > userspace before? > After userspace call virtqueue_push(), it always call virtio_notify() immediately. In traditional VM (vhost-vdpa) cases, virtio_notify() will inject an irq to VM and return, then vcpu thread will call interrupt handler. But in container (virtio-vdpa) cases, virtio_notify() will call interrupt handler directly. So it looks like we have to optimize the virtio-vdpa cases. But one problem is we don't know whether we are in the VM user case or container user case. Thanks, Yongji
