Debugging kernel memory usage

[Ralf Ertzinger]

Hi.

I have a current rawhide system which (running Gnome, Firefox and Claws)
uses 1.7 Gigs of RAM (+256MB in Swap, caches and buffers already subtracted).
The system has 3 Gig, so that's not an immediate problem, but I'd sure like
to know where all that memory has gone.

top shows no obvious offenders in the memory department, and I'm not
really sure how to read /proc/{meminfo,slabinfo,zoneinfo}. Is there
a webpage detailing how to find out how much memory the kernel uses
for it's own purposes, possibly sorted by the module that allocated it?