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

*** 858,876 ****
          }
          fpp->fpu_en = 0;
          fpp->fpu_fprs = 0;
  }
  
- void
- lwp_swapin(kthread_t *tp)
- {
-         struct machpcb *mpcb = lwptompcb(ttolwp(tp));
- 
-         mpcb->mpcb_pa = va_to_pa(mpcb);
-         mpcb->mpcb_wbuf_pa = va_to_pa(mpcb->mpcb_wbuf);
- }
- 
  /*
   * Construct the execution environment for the user's signal
   * handler and arrange for control to be given to it on return
   * to userland.  The library code now calls setcontext() to
   * clean up after the signal handler, so sigret() is no longer
--- 858,867 ----