shared memory and swapping

[Al Globus]

Does SGI OS 3.3.1 lock shared memory regions in core?  I have
some evidence that it does.

I'm using the FAST visualization environment.  It puts solution
data in shared memory.  Solution data is big.  If I leave the
solutions in shared memory and do something else that requires
a lot of memory (but no the solutions) I get a ton of swapping.
If I then delete the solutions (in shared memory), I see the
memory usage in 'gr_osview -a' go down!  But I haven't accessed
the solution data for a while and it should have been paged out.
Any ideas about what's going on?  Thanx.