No idea, but you can get the same information also from /proc/PID/smaps.
It's separate for each of the memory mapping the process has i.e. you may
need to write a small script to process the data.
If the process has stuff that's marked as swapped, but not anymore as
dirty, it's completely swapped out. For some reason kernel/SMAPS doesn't
think swapped pages to be anymore dirty which loses the distinction
between shared dirty and private dirty that SMAPS shows for pages still in