Random x86-64 seg-fault finally fixed

[Matthew Dillon]

   The random utility seg-fault (usually cc1) on x86-64 appears to have
   finally been fixed.  It turned out to be a vm_page race in the pageout
   demon when it cycles pages onto the free page list.

   This clears the way for running the system with the remaining global
   tokens set to MPSAFE mode.  Test boxes are now running that way with no
   errors so I expect we will be changing the tokens to run MPSAFE after
   christmas sometime.  We do still have to audit the code paths.

   I also expect to have a fine-grained VM solution at least for standard
   VM faults by the next release, hopefully sooner.  It appears to be the
   biggest bottleneck on the monster 48-core test box now.

   Sascha has brought in the mps disk driver which is now undergoing
   testing.  This is the last big chipset support piece needed for 48-core
   opteron supermicro support.  The Gigabit ethernet uses the igb driver
   which seems to work pretty well in polling mode.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>