Comment by xroche

> And if you really want it, it's not terribly hard to write

Sure, but basically it means rewriting all structures that rely on a bucket of stuff.

By the way maps often use a large bucket, and rehash in-place can be preferable.

> Which not many do, not unless the allocation is so large as to be in its own dedicated mmap

Do you know a modern operating system that does not have a mremap equivalent ?

On Linux you pretty much use it as soon as you reach large blocks.