This is quite interesting since I, too, was under the impression that mmap cannot be used on disk-backed files with huge pages. I tried and failed to find any official kernel documentation around this, but I clearly remember trying to do this at work (on a regular ECS machine with Ubuntu) and getting errors.
Based on this SO discussion [1], it is possibly a limitation with popular filesystems like ext4?
If anyone knows more about this, I'd love to know what exactly are the requirements for using hugepages this way.
[1] https://stackoverflow.com/questions/44060678/huge-pages-for-...