- Increase the active lru refresh interval to 10 minutes.  This has been
   shown to negatively impact some workloads and the goal is only to
   eliminate worst case behaviors for very long periods of paging
   inactivity.  Eventually we should determine a more complex scaling
   factor for this feature.
 - Rate limit low memory callback handlers to limit thrashing.  Set the
   default to 10 seconds.

Sponsored by:	EMC / Isilon Storage Division