[popcornmix]

UPDATE: I closed video player and still GPU= 938k

When I killed XBMC and restarted GPU_MEM went to 62MB
https://www.dropbox.com/s/g12jefyllt2e09....35.52.png

Try running and quitting xbmc a few times. Measure gpu_mem and see what sort of value it normally has when xbmc is not running.
After the "blocks" problem, quit xbmc and see if gpu_mem is at it's normal level, or is it lower.

If it's lower than normal, then the problem is on gpu, as (vritually) all gpu memory allocated by xbmc should be released when xbmc exits. (1)
If it returns to normal, then it's an xbmc bug of not releasing memory. (2)

Code:

vcgencmd cache_flush && sudo vcdbg reloc

can show you the memory allocated on gpu. Note this is a debug feature that parses memory structures without stopping the gpu,
so it can get out of sync when allocations occur when reading. Run it a couple of times if results are suspicious.

In case (1), then post result of vcdbg after xbmc is quit. The missing memory should be visible (with allocation names) and should give some clues.
In case (2), it's a bit trickier. You'll have to look for the "extra" allocations when it's in the "blocks" state (perhaps by running diff on a sequence of vcdbg logs).