dual-single core Opteron -- so, two cores total -- with a 3.0 GENERIC.MP
kernel.  Because of the memorylocked issue, to run a 7GB memtest I have
to configure a few hundred megabytes of swap.

A 4GB memtest runs fine; so does 5; I didn't try 6.

However, a 7GB memtest gives a quick and irretrievable system hang.  The
system appears unable even to drop to DDB.

I'm really not even sure how to start debugging this.

-- 
  Thor Lancelot Simon	                                     tls@rek.tjls.com

  "We cannot usually in social life pursue a single value or a single moral
   aim, untroubled by the need to compromise with others."      - H.L.A. Hart