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.
https://bugs.launchpad.net/gala/+bug/1488183
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: