swap file used but unchanged

["Jeremy C. Reed" <reed%reedmedia.net@localhost>]

I have:

$ swapctl -l
Device         512-blocks     Used    Avail Capacity  Priority
/root/swapfile      20000    20000        0   100%    1

But that swapfile has not changed. It is all Ctrl-@. (Any hints on using 
grep to verify this?) md5 shows it has not changed.

The file permission is mode 0. I don't imagine that is stopping the 
kernel, but maybe it is. But if so, why does the capacity grow to 100%?

What does this mean that swapctl shows it is used even though no data 
changes in it? swapctl showed it prevously at different capacities so 
showed it was getting used more and more.

  Jeremy C. Reed