Memory Mangement Problem in 5.1-RELEASE

[Bill Moran]

Ahmed Al-Hindawi wrote:
> Hi,
> I have 160Mb of SDRAM (PC100) on a 233Mhz CyrixInstead machine and I
> seem to have memory mangament problems. The BIOS indicates I have 160,
> so does the BSD bootstrap program. 
> 
> When I launch GNOME 2.2 everythings is good as gold untill I open the
> System monitor program. It says that I have 149 Mb of RAM which is fine
> ( 4Mb of video..and the rest...god knows).
> 
> I open every program I have and after 107Mb the machine starts to swap
> with about 50Mb left unused!!
> 
> I recompliled the GENERIC kernal for the sake of it really (Im still an
> amature) I didn't mess with the configuration files or anything (I just
> don't know how!!).
> 
> Is this normal or mismanagement of memory in the 5.1 version of the
> excellent FreeBSD kernel??

The mistake is in the way the Gnome System Monitor display the free memory.

I just watched both 'top' and the System Monitor as I opened program after
program until the system started swapping, and System monitor reports
almost 100M free while top reported less than 10M.

To _always_ have a little memory free is A Good Thing(tm).  FreeBSD has
some pretty advanced memory management that will start swapping _before_
the system runs out of RAM.  However, the System Monitor's display of
this is simply inaccurate.  There was NOT 100M free when it started swapping
on my system.

-- 
Bill Moran
Potential Technologies
http://www.potentialtech.com