4.9 boot problem on em0 platform.

[Don Bowman]

From: Deepak Jain [mailto:deepak at ai.net]
> > Just a guess, but i think you've bumped nmbclusters or nmbufs up
> > too much (or perhaps maxsockets, maxfds, ...) and have run out of
> > KVA.
> > 
> > You can tune clusters & mbufs in loader.conf without recompiling
> > kernel. You will want to see what vm.zone_kmem_pages, 
> vm.zone_kmem_kvaspace
> > are showing you, vmstat -z, vmstat -m, etc.
> > 
> > You may want to alter VM_KMEM_SIZE_SCALE to e.g. '2' if you are
> > trying to put more into the kernel mem space.
> > 
> 
> The kernel that works from another machine has the same settings 
> (NMBCLUSTERS=65536, maxusers=512). The machine has 2GB of RAM.
> 
> How do you undo the loader.conf settings when the machine won't boot 
> because of the settings you made? :|

Use 'space' to get to the 'ok' loader prompt.
now 'set' the values to a lower #...

ok set path.path.path=value


man loader will tell you about this.