> OTOH, if for some compelling reason it's believed Python knows better
> than platform vendors, then obmalloc should be uglied-up on all paths to
> make the enlightened choice.

I'm proposing that obmalloc is changed to know better than system malloc
on systems supporting anonymous mmap, and Windows, and that the call

   malloc(ARENA_SIZE)

is replaced by mmap. This has the advantage of doing better than system
malloc on Solaris, plus it also might guarantee that arenas will be
POOL_SIZE aligned.

OTOH, the calls

  realloc(arenas, nbytes)
  malloc(nbytes)

should continue to go to system malloc, because they are typically
not multiples of the system page size.