Comment 141 for bug 1572801

I don't think this is strictly a Unity problem. I recently noticed that gnome-shell was eating memory in Ubuntu 16.04.2 (64-bit), consuming all available RAM and SWAP space before ultimately resulting in errors resembling, "Unable to fork: Cannot allocate memory," which occurred when launching any application within Gnome. Rebooting the server freed up memory temporarily, but didn't fix the problem. It appears to be a bug involving the proprietary NVIDIA display drivers. Maybe identical to this bug report, which was supposedly patched last year:
https://devtalk.nvidia.com/default/topic/879616/linux/memory-leak-for-gnome-shell-for-gdm-user-all-driver-versions-/post/4685195/

In the meanwhile, switching back to the open-source Nouveau display drivers seems to have stopped the memory leak. Unfortunately I have a few games on Steam that perform better with the proprietary drivers, so I hope this is something that gets fixed.