vhost: virtio-net rx-ring stop work after work many hours, bug?

[Linhaifeng <haifeng.lin-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>]

Hi,all

I use vhost-user to send data to VM at first it cant work well but after many hours VM can not receive data but can send data.

(gdb)p avail_idx
$4 = 2668
(gdb)p free_entries
$5 = 0
(gdb)l
        /* check that we have enough buffers */
        if (unlikely(count > free_entries))
            count = free_entries;

        if (count == 0){
            int b=0;
            if(b) { // when set b=1 to notify guest rx_ring will restart to work
                if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)) {

                    eventfd_write(vq->callfd, 1);
                }
            }
            return 0;
        }

some info i print in guest:

net eth3:vi->num=199
net eth3:rvq info: num_free=57, used->idx=2668, avail->idx=2668
net eth3:svq info: num_free=254, used->idx=1644, avail->idx=1644

net eth3:vi->num=199
net eth3:rvq info: num_free=57, used->idx=2668, avail->idx=2668
net eth3:svq info: num_free=254, used->idx=1645, avail->idx=1645

net eth3:vi->num=199
net eth3:rvq info: num_free=57, used->idx=2668, avail->idx=2668
net eth3:svq info: num_free=254, used->idx=1646, avail->idx=1646

# free
             total       used       free     shared    buffers     cached
Mem:      3924100      337252    3586848          0      95984     138060
-/+ buffers/cache:     103208    3820892
Swap:       970748          0     970748

I have two questions:
1.Should we need to notify guest when there is no buffer in vq->avail?
2.Why virtio_net stop to fill avail?






-- 
Regards,
Haifeng