Hi,
If you want to see which user is using how much of the page please go to SM04 ->goto -> memory.
You will get all the list.
In some case certain cases the work process the work process will still hold the memory even if the user is logged of . Please check if you have any of those session and is using page.
Did you do kernel upgrade and after that you are having this issues or your system has not been rebooted for many days.
Thanks
Rishi abrol