ASP.Net Identity sign-out all sessions

How do you sign-out all sessions with ASP.NET Identity?
Lets say you are signed-in from two different browser with the same user. When the user signs-out from one browser, the session of the other browser should be invalidated as well.
(I need this to invalided all sessions of a user on password change.)

Using Session to store Datatable

currently we are using Sessions to store datatables in our pages so that we don’t have to make Database hits to get the same datatable again and again. But my worry is that it is using the server memory and if large number of users login some day, the response of the server will become slow and our application might crash as well.