about netmap num_rx_desc.

in netmap_kern.h
struct netmap_adapter {

......

u_int num_rx_desc;
//u_int buff_size; // XXX deprecate, use NETMAP_BUF_SIZE


but in netmap.c

int
netmap_attach(struct netmap_adapter *na, int num_queues)
{
....
na->num_rx_rings = num_queues;

ixgbe_netmap.h

static void
ixgbe_netmap_attach(struct adapter *adapter)
{
...
netmap_attach(&na, adapter->num_queues);
}

why not use the netmap_buf_size as na->num_rx_rings;
then will be have a larger buffer