vnet_tx_dring_avail
if (unlikely(vnet_tx_dring_avail(dr) < gso_segs)) {
if (vnet_tx_dring_avail(dr) < skb_shinfo(skb)->gso_segs)
if (unlikely(vnet_tx_dring_avail(dr) < 1)) {
if (unlikely(vnet_tx_dring_avail(dr) < 1)) {
if (vnet_tx_dring_avail(dr) > VNET_TX_WAKEUP_THRESH(dr))
vnet_tx_dring_avail(dr) >= VNET_TX_WAKEUP_THRESH(dr)))