Re: [PATCH v23 2/2] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_VQ

[Wei Wang]

On 01/24/2018 01:01 PM, Michael S. Tsirkin wrote:
> On Wed, Jan 24, 2018 at 10:50:27AM +0800, Wei Wang wrote:
> This will not DTRT in all cases. It's quite possible
> that host does not need the kick when ring is half full but
> does need it later when ring is full.
> You can kick at ring half full as optimization but you absolutely
> still must kick on ring full. Something like:
>
> if (vq->num_free == virtqueue_get_vring_size(vq) / 2 ||
> 	vq->num_free <= 2)

Right. Would "if (vq->num_free < virtqueue_get_vring_size(vq) / 2" be 
better?


Best,
Wei