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

*** 764,774 ****
          segmf_fault,
          segmf_faulta,
          segmf_setprot,
          segmf_checkprot,
          (int (*)())segmf_kluster,
-         (size_t (*)(struct seg *))NULL, /* swapout */
          segmf_sync,
          segmf_incore,
          segmf_lockop,
          segmf_getprot,
          segmf_getoffset,
--- 764,773 ----