On Tue, 04 Aug 1998 14:58:59 -0700 
 Jason Thorpe <thorpej@nas.nasa.gov> wrote:

 >  > This machine has 67108864 bytes of real memory so where did the 16113664
 >  > bytes go?
 >  > 
 >  > I assume that the kernel is using this much memory?
 > 
 > Some of it is buffer cache (spelled out in kernel messages), some of it
 > is overhead of kernel page tables needed to map the various pieces of
 > kernel address space.

And to follow-up on this, with some simple instrumentation in
pmap_steal_memory():

Entering netbsd at 0xfffffc0000300fc0...
[ preserving 155592 bytes of netbsd symbol table ]
Copyright (c) 1996, 1997, 1998
    The NetBSD Foundation, Inc.  All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
    The Regents of the University of California.  All rights reserved.

NetBSD 1.3G (BISHOP) #424: Tue Aug  4 15:09:45 PDT 1998
    thorpej@bishop:/tmp_mnt/dracul/u5/netbsd/src/sys/arch/alpha/compile/BISHOP
Digital AlphaStation 500/500, 500MHz
8192 byte page size, 1 processor.
real mem = 268435456 (2252800 reserved for PROM, 266182656 used by NetBSD)
avail mem = 230948864
stolen memory for VM structures = 4849664 bytes
using 3249 buffers containing 26615808 bytes of memory

...ok, plus kernel: 2310080 on my system.  Note that avail mem is also
printed after the kernel malloc has been allowed to run, so there may
be some pages that have been given to the malloc engine already.

Jason R. Thorpe                                       thorpej@nas.nasa.gov
NASA Ames Research Center                            Home: +1 408 866 1912
NAS: M/S 258-5                                       Work: +1 650 604 0935
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