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

*** 119,132 ****
  
  struct as;
  struct page;
  struct anon;
  
- extern int maxslp;
  extern ulong_t pginrate;
  extern ulong_t pgoutrate;
- extern void swapout_lwp(klwp_t *);
  
  extern  int valid_va_range(caddr_t *basep, size_t *lenp, size_t minlen,
                  int dir);
  extern  int valid_va_range_aligned(caddr_t *basep, size_t *lenp,
      size_t minlen, int dir, size_t align, size_t redzone, size_t off);
--- 119,130 ----