dev.netmap.buf_size and packett size from host

[Eduardo Meyer]

hello,

I have a netmap application which has host mode bridge/fwd, with default
settings I have the following error some often:

884.260394 [2950] netmap_transmit           igb1 from_host, drop packet
size 2962 > 2048

the only application which relies on host mode is bird, so those packets
are probably from bird daemon, when I get those errors I get bird sessions
failing and restart

I raised dev.netmap.buf_size to 5000 it ajusted to 5120, things got better
but I still have logs:

netmap_transmit           igb1 from_host, drop packet size 5858 > 5120

Now the main question is, when dev.netmap.buf_size is 2048 the application
uses 1.3G of RAM but when I raise to 5120 it uses 3G of RAM.

So I need to understand, is this packet size really related from what I get
from the application packets coming from host to netmap? If so can I allow
for bigger sizes, like 16k (lo0 mtu) without pre-alloc so much more RAM?

thank you

E. Meyer