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

*** 107,117 ****
          segmap_fault,
          segmap_faulta,
          SEGMAP_BADOP(int),      /* setprot */
          segmap_checkprot,
          segmap_kluster,
-         SEGMAP_BADOP(size_t),   /* swapout */
          SEGMAP_BADOP(int),      /* sync */
          SEGMAP_BADOP(size_t),   /* incore */
          SEGMAP_BADOP(int),      /* lockop */
          segmap_getprot,
          segmap_getoffset,
--- 107,116 ----