tmpfs - Handle low memory situations a little better (2)

tmpfs - Handle low memory situations a little better (2)

* When handling pageout daemon requests we want to try to free pages
  directly to the VM page cache or the freeq and not necessarily cycle
  them through active or inactive.

  Shortcutting to the cache/free queues will allow the machine to
  unstick much more quickly which is particularly important on boxes
  with a lot of memory because the pageout hysteresis runs in such a
  large range.

* Greatly improves monster's performance under extreme tmpfs write loads.