remove whole-process swapping
Long before Unix supported paging, it used process swapping to reclaim
memory.  The code is there and in theory it runs when we get *extremely* low
on memory.  In practice, it never runs since the definition of low-on-memory
is antiquated. (XXX: define what antiquated means)
You can check the number of swapout/swapin events with kstats:
$ kstat -p ::vm:swapin ::vm:swapout

*** 1213,1224 ****
          nrp->req = req;
          nrp->cr = cr;
          nrp->ro = ro;
          nrp->thread = curthread;
  
-         ASSERT(curthread->t_schedflag & TS_DONT_SWAP);
- 
          /*
           * Look to see if there is already a cluster started
           * for this file.
           */
          mutex_enter(&rfs_async_write_lock);
--- 1213,1222 ----