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

@@ -1108,18 +1108,10 @@
 sysdc_globpri(kthread_t *t)
 {
         return (t->t_epri);
 }
 
-/*ARGSUSED*/
-static pri_t
-sysdc_no_swap(kthread_t *t, int flags)
-{
-        /* SDC threads cannot be swapped. */
-        return (-1);
-}
-
 /*
  * Get maximum and minimum priorities enjoyed by SDC threads.
  */
 static int
 sysdc_getclpri(pcpri_t *pcprip)

@@ -1200,12 +1192,10 @@
                 sysdc_enosys,   /* parmsset */
                 sysdc_nullsys,  /* stop */
                 sysdc_exit,
                 sysdc_nullsys,  /* active */
                 sysdc_nullsys,  /* inactive */
-                sysdc_no_swap,  /* swapin */
-                sysdc_no_swap,  /* swapout */
                 sysdc_nullsys,  /* trapret */
                 sysdc_preempt,
                 sysdc_setrun,
                 sysdc_sleep,
                 sysdc_tick,