I can’t say I understand that, either. If the goal is to prevent the mmap’ed file from persisting on disk, using tmpfs handles that. If the goal is to prevent

I can’t say I understand that, either. If the goal is to prevent the mmap’ed file from persisting on disk, using tmpfs handles that. If the goal is to prevent other processes from accessing the mmap’ed file, the systemd fd store would have the same issue.