linux - What is the difference between swap entries in fstab?

I've been looking around and seen two different things ways to declare swap in fstab.

I've seen something like the line below:

UUID=UUID-HERE none swap sw 0 0

and

UUID=UUID-HERE none swap swap 0 0`

What, if anything, is the difference?

Answer

When the filesystem type is swap, neither of these options mean anything. In fact, the only option that makes sense is pri=n, specifying the swap space priority. Usually you don't need it and can just specify defaults:

UUID=foo   none   swap   defaults

(The mount point, as well as dump and pass fields, are irrelevant too.)