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

*** 281,291 ****
  int     as_gap_aligned(struct as *as, size_t minlen, caddr_t *basep,
              size_t *lenp, uint_t flags, caddr_t addr, size_t align,
              size_t redzone, size_t off);
  
  int     as_memory(struct as *as, caddr_t *basep, size_t *lenp);
- size_t  as_swapout(struct as *as);
  int     as_incore(struct as *as, caddr_t addr, size_t size, char *vec,
                  size_t *sizep);
  int     as_ctl(struct as *as, caddr_t addr, size_t size, int func, int attr,
                  uintptr_t arg, ulong_t *lock_map, size_t pos);
  int     as_pagelock(struct as *as, struct page ***ppp, caddr_t addr,
--- 281,290 ----