https://bugzilla.kernel.org/show_bug.cgi?id=31412
--- Comment #9 from Dave Airlie airlied@linux.ie 2011-03-19 22:07:30 --- I'm having trouble reconciling this with the graphics driver.
a) you claim it happens with fglrx as well, there is nothing shared between them (so it can't be a common gpu bug)
b) nothing is leaking according to that debug info in anywhere obvious.
One last test would be unload the gpu stack to see what happens
got to runlevel 3 or anywhere X isn't rnunig echo 0 > /sys/class/vtconsole/vtcon1/bind rmmod radeon ttm drm_kms_helper drm
see if memory is still gone.
maybe you can watch /proc/slabinfo to see where the memory might be going. It might also just be page cache from the pdf loading,
does echo 3 > /proc/sys/vm/drop_caches help?