igb(4) won't start with "igb0: Could not setup receive structures"

[Andrey Zonov]

Hi,

New igb driver (and I think em too) is required too much 9k mbufs when 
it's been configured with mtu = 9000. On machine with 8 CPUs, driver is 
required 8192 9k mbufs, but by default there is only 6400 and network 
won't start. In previous versions for big mtu it was used 4k mbufs, by 
default there is 12800 and all worked fine.

Maybe it's time to think about increasing default 
kern.maxusers/kern.ipc.nmbclusters? or use mp_ncpus for calculation 
these values? or just increase amount of 
mbuf_cluster/mbuf_jumbo_page/mbuf_jumbo_9k from that driver...

I just want igb to work out-of-the-box.

-- 
Andrey Zonov