knfsd and memory usage

[Brian]

So I have this new file server (2.4.16), and it's memory looks like
Mem:    771952K total,   767492K used,     4460K free,    22016K buffers
Swap:        0K total,        0K used,        0K free,    71848K cached

So cache, buffers, and free memory account for ~100MB.
There are a handful of userspace processes taking ~20MB.

Obviously I expect the kernel to take up some memory, but 650 megs?

Is there I way I can find out where all of that memory went?
If knfsd is hoarding (no other box has this much unaccounted for), is 
there a way to tweak it at runtime?  Are there 'safe' things to adjust at 
compile time?

Thanks
	-- Brian