[dpdk-dev] [PATCH v2 02/24] virtio: Use weaker barriers

[Ouyang, Changchun]

Hi Stephen,
Although it is original code logic, 
But we can move vq_update_avail_idx(rxvq) into if block to resolve it.
What do you think of it?

Thanks
Changchun

-----Original Message-----
From: Xie, Huawei 
Sent: Tuesday, January 27, 2015 3:57 PM
To: Ouyang, Changchun; dev at dpdk.org
Cc: Stephen Hemminger (stephen at networkplumber.org)
Subject: RE: [dpdk-dev] [PATCH v2 02/24] virtio: Use weaker barriers

>-------if (likely(nb_enqueued)) {
>------->-------virtio_wmb();
>------->-------if (unlikely(virtqueue_kick_prepare(rxvq))) {
>------->------->-------virtqueue_notify(rxvq);
>------->------->-------PMD_RX_LOG(DEBUG, "Notified\n");
>------->-------}
>-------}
>-------vq_update_avail_idx(rxvq);


Two confuses for the modification here:

1.
why notify host without updating avail idx?
Will this cause potential deadlock?

2.
Why update avail index even no packets are enqueued?