xskq_nb_queue_empty_descs
xs->pool ? xskq_nb_queue_empty_descs(xs->pool->fq) : 0;
stats.tx_ring_empty_descs = xskq_nb_queue_empty_descs(xs->tx);
du.n_fill_ring_empty = xs->pool ? xskq_nb_queue_empty_descs(xs->pool->fq) : 0;
du.n_tx_ring_empty = xskq_nb_queue_empty_descs(xs->tx);