"More information on priority: A scenario that might exist in
which you would need this, is if you decide to add another swap,
but have it within a file rather than partition new space for it.
You can set the partition to a priority of 5 and the new swap file
to Priority of 1. Because the highest value is always preferred,
this will ensure that the swap partition is used before the swap
file. Another case is spreading the swap over multiple separate
drives. If the priority is set the same for both swap devices, the
kernel will utilize them in a manner similar to a striped array
(round-robin). When it comes time to write to disk, this can help
increase performance a bit."