You can set the priority of swap in Linux by
For example, to set
/dev/sdc1's priority to 0:
# swapoff /dev/sdc1; swapon -p 0 /dev/sdc1
You can also put one entry into the
/etc/fstab to make it take effect each time Linux reboots:
/dev/sdc1 swap swap pri=0 0 0
You can set 2 swap partions to have the same priority, pages are allocated on a round-robin basis between them.
Each swap area has a priority, either high or low. The default
priority is low. Within the low-priority areas, newer areas are even
lower priority than older areas. All priorities set with swapflags are
high-priority, higher than default. They may have any non-negative
value chosen by the caller. Higher numbers mean higher priority.
Swap pages are allocated from areas in priority order, highest
priority first. For areas with different priorities, a higher-priority
area is exhausted before using a lower-priority area. If two or more
areas have the same priority, and it is the highest priority
available, pages are allocated on a round-robin basis between them.
As of Linux 1.3.6, the kernel usually follows these rules, but there
From swapon manual.