Problem Description
Check the nvidia-smi command, there are two processes occupying some video memory resources.
If the server uses the command line, this process can be closed.
shutdown method
sudo service gdm stop
Then it worked!
What is Gnome-Shell?
Gnome Shell is the main component of GNOME 3. It reforms the operation of the GNOME desktop environment, including window management, application startup and workspace management, and provides users with a new convenient and easy-to-use desktop management method. The gnome shell is essentially a collection of window managers, application launchers, and desktop layouts. Most graphics code is written in JavaScript.
In view of the fact that such introductions are easier to find on the Internet, I won't make too many records here!
For more reference:
Baidu Encyclopedia: http://baike.baidu.com/view/2401635.htm
gnome official website introduction: https://live.gnome.org/GnomeShell/FAQ