Setting aside the wisdom of this approach, if you were going to do this why wouldn&#x27;t you just use malloc() to allocate the single large arena that you&#x27;re going to allocate from yourself?  It&#x27;s still just one free().<p>In other words, the malloc-versus-mmap distinction here isn&#x27;t the important one, it&#x27;s the custom allocator versus system allocator one.