kernel_map

[Василий Петров]

Is any way to find out how much kernel virtual address space is used and how 
much is free?
I'm getting troubles overflowing this so I want to know how much of KVA space 
is free on box.
As I understood, complete data on KVA space usage kept in kernel_map object. 
As it resides in KVA space itself I can access it with kvm_read. But I have 
no idea of how to determine its address in KVA space. Is any way to do that 
from userland program?
Generally, maybe there is other way to get KVA space usage info?

PS: I mean exactly preallocated for buffers KVA space, not memory allocated 
for buffers. As I see this is different things, as system reserves space in 
KVA space for maximal size of kernel buffers. And system will crash on boot 
if buffers limit is too high, and not upon allocating that much space. So I 
want to know info about that reservation to know how much can I grow buffer 
limits (especially kern.nbuf).