In Activity Monitor, how can Swap Used be more than Page Outs? I am trying to understand the relationship between Page Outs and Swap Used as displayed in Activity Monitor.  Currently, Activity Monitor shows:

Page outs:  1.6 MB
Swap used:  8.1 MB

How can there be more swap used than the amount paged out?
My understanding is this:


Program needs access to some data.  Attempts to do so, and fails, due to lack of RAM.
OS takes control.  There is a page-out operation, where physical RAM is copied to swap.
There is a page-in operation, where the required data is copied to RAM.
OS gives control back to program.
Program tries again, finds its data.


OS's are getting smart about how they choose what and when to to page in/out.  So the operation counts may not be the same, and the swap space may perhaps be in use without there being page outs.

Unless of course I'm backwards on what a page-in/page-out operation is.  In which case your question makes perfect sense.