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

*** 780,790 ****
          segkmem_fault,
          SEGKMEM_BADOP(faultcode_t),     /* faulta */
          segkmem_setprot,
          segkmem_checkprot,
          segkmem_kluster,
-         SEGKMEM_BADOP(size_t),          /* swapout */
          SEGKMEM_BADOP(int),             /* sync */
          SEGKMEM_BADOP(size_t),          /* incore */
          SEGKMEM_BADOP(int),             /* lockop */
          SEGKMEM_BADOP(int),             /* getprot */
          SEGKMEM_BADOP(u_offset_t),      /* getoffset */
--- 780,789 ----