[pocak]

Linux allocates page tables lazily, and fills them lazily. The only upfront work is to mark the virtual address range as valid and associated with the file. I'd expect mapping giant files to be fast enough to not need windowing.

[jabl]

Good point, scratch that part of my answer.

There are still some cases where you'd not want unlimited VM mapping, but those are getting a bit esoteric and at least the most obvious ones are in the process of getting fixed.