Virtualization - Mar 2021 - [RFC v4 10/11] vduse: Introduce a workqueue for irq injection

On 2021/3/4 4:58 ??, Yongji Xie wrote:
> On Thu, Mar 4, 2021 at 2:59 PM Jason Wang <jasowang at redhat.com>
wrote:
>>
>> On 2021/2/23 7:50 ??, 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?

Thanks

>
> Thanks,
> Yongji
>