Regardless of whether recording each action affects the performance of the application request?

We store the user's permission information in the session object on a successful login. We read this session object in every action. When accessing the session, if the session is Null, we reinitialize the session. We are using MVC 5. My queries are: 1. Because in every action there may be chances of re-initializing the session (if the session is Null). Does this affect application response time? 2. In doing this, each request locks the session object. How can I avoid blocking the session?

Thank you, Kannan Esvar.