Gala is using 9.5 GB of memory. This is after running for about 2 days. There is obviously some kind of memory leak. Is this known and is there any work being done on it?
Known: Yes, Fixed: Seem Not Yet as there is a bug report still open.
You can register in launchpad and flag that bug as it does affect you. So it will get more light.
Seems there is some other users facing same bug: