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

*** 79,90 ****
          int     (*cl_parmsset)(kthread_t *, void *, id_t, cred_t *);
          void    (*cl_stop)(kthread_t *, int, int);
          void    (*cl_exit)(kthread_t *);
          void    (*cl_active)(kthread_t *);
          void    (*cl_inactive)(kthread_t *);
-         pri_t   (*cl_swapin)(kthread_t *, int);
-         pri_t   (*cl_swapout)(kthread_t *, int);
          void    (*cl_trapret)(kthread_t *);
          void    (*cl_preempt)(kthread_t *);
          void    (*cl_setrun)(kthread_t *);
          void    (*cl_sleep)(kthread_t *);
          void    (*cl_tick)(kthread_t *);
--- 79,88 ----
*** 194,207 ****
  
  #define CL_ACTIVE(t)            (*(t)->t_clfuncs->cl_active)(t)
  
  #define CL_INACTIVE(t)          (*(t)->t_clfuncs->cl_inactive)(t)
  
- #define CL_SWAPIN(t, flags)     (*(t)->t_clfuncs->cl_swapin)(t, flags)
- 
- #define CL_SWAPOUT(t, flags)    (*(t)->t_clfuncs->cl_swapout)(t, flags)
- 
  #define CL_TICK(t)              (*(t)->t_clfuncs->cl_tick)(t)
  
  #define CL_TRAPRET(t)           (*(t)->t_clfuncs->cl_trapret)(t)
  
  #define CL_WAKEUP(t)            (*(t)->t_clfuncs->cl_wakeup)(t)
--- 192,201 ----