[victorlf]

I you run a very memory hungry program (like some specific scientific program), it can happen that 3GB of your memory from the browser, text editor, etc. is moved to swap. Then, when you kill the program and want to go back to normal, just changing the tab in your browser can take a long time.

By flushing the swap, you wait some time first but then it all runs smoothly. When using a hard drive and not SSD the difference is even bigger.

[joosters]

I've hit the same kind of problem before. Big task runs & eats all the memory. Later on, a login to the machine or existing shells are horribly slow until they get swapped back in.

However, swapoff/swapon only solves part of the problem - you still have binaries, libraries and other file-backed memory that were thrown out under the memory pressure and they won't be reloaded with the swapoff/swapon. Does anyone know how to force these kinds of things to be re-loaded before they are needed again?