ifconfig em0 mtu 9000 does not update the routing table

[Nikolay Denev]

Hello,

As the subject says, I'm trying to enable jumbo frames on running  
machine by setting
ifconfig em0 mtu 9000 by hand, but nothing changed, and I've fount  
that when I list
the routing table with the MTU column it shows the connected routes  
still with MTU 1500.
Is this supposed to work this way? I understand that making ifconfig  
touch the routing table is ugly hack, but maybe the routing code can  
be notified for interface changes by some other mechanism?

btw, this is on 7-STABLE with if_em(4) interfaces.

--
Regards,
Nikolay Denev