What is the maximum memory that Jupyterhub can use?

Jupyterhub displays a maximum of 32GB, but I can use as much as 7GB in normal use.
Can you tell me how to use the maximum memory as much as possible?

JupyterHub does not put any limits itself but you need to configure it with appropriate Linux tools. Saying that this highly depends on which JupyterHub spawner you use in your configuration. So please share information about that.

A different question: How did you realize that your memory is limited? How did you log your memory consumption? Why do you say its 7GB?