CTStats memory graphs for CTools 2.9 show a continuously increasing permanent consumption of memory. This is apparent in the graphs for free space, perm gen space used and old gen space. Fortunately weekly restarts clean up the problem, but this implies that the weekly restarts are necessary and that we have less and less headroom to cope with abbarent behavior as the week goes on.
The attached image and this graph clearly demonstrate the issue:
We should compare two heap dumps, taken on the same server, on different days in a single week. This would allow the Eclipse memory analyzer tool to find what is different between between the heap dumps and would point to the problematic data. (Yourkit also might be able to do the analysis.)