The first thing that comes to mind is a "reliable" (that won't overcommit) memory allocation syscall, but one might fear that it will abused (everyone wants the

The first thing that comes to mind is a "reliable" (that won't overcommit) memory allocation syscall, but one might fear that it will abused (everyone wants the best stuff even if they might not use it after all). The second thing that comes to mind is to able to probe a (virtual) address (address range) within your addressing space, to check if it's actually there without doing weird stuff, and eventually just wait until it becomes available. But at this point maybe you could just use file-backed mmap for big data (effectively managing your own swap space)?