How to determine the amount of free kernel memory?

[Michael Bellion]

Hi

Is there a way to determine the amount of free kernel memory?
si_meminfo() returns nr_free_pages() for example, but this is
not what I'm looking for.
I want to know the amount of memory that is available to the kernel (via 
vmalloc or kmalloc) without considering userspace memory consumption.

Maybe something like:
nr_active_pages + nr_inactive_pages + nr_free_pages()

I want to use the functionality from within a kernel module, so i don't have 
access to nr_active_pages(), nr_inactive_pages() or nr_free_pages().

Thanks for your help.
	Michael Bellion