txq_hw_head
for (head = txq_hw_head(q), reclaim_idx = q->cons_cnt & q->mask;
head != reclaim_idx && npkts < limit; head = txq_hw_head(q)) {
for (head = txq_hw_head(q), reclaim_idx = q->cons_cnt & q->mask;
head != reclaim_idx && npkts < budget; head = txq_hw_head(q)) {