Free memory seems low

[Jim Barton]

In article <1991Jan24.155817.22594 at rice.edu>, anand at crysiris.rice.edu
(Anand Kolatkar) writes:

> 	I work on a 4D-20 (3.3.1) with 8M memory.
> 
> 	When I login when noone else is logged on or running anything, 
> 	osview shows only 1.2M of memory available (if I am logged in
> 	from a non console terminal) and 400-500K of memory when I
> 	login from the console.  This is the free memory showed by osview.
> 
> 	Is it normal to have only 1/8 of the memory available?
> 
> 	Any answers would be appreciated.

The "Free" line for memory is the amount of memory that currently has no
valid data. In 3.3 and later systems, all of memory is treated as a
cache. All of the memory which is specified as "Userdata" is available
as well. This memory can in general be stolen immediately, since there
is a valid copy of it on backing store.

The only memory unavailable for the user is "Locked" (typically kernel,
but can include memory locked using plock(2) or mpin(2)), "Sysdata"
(process specific data) and "Delwri" (memory on the way to disk). The
gr_osview(1) man page describes these things in gory detail, and the
information applies equally to osview(1).

My guess is that 5-6MB of memory is actually available with Userdata and
Free added together.

-- Jim Barton
   Silicon Graphics Computer Systems
   jmb at sgi.com