Swapon

swapon/swapoff enable/disable devices and files for paging and swapping and it is included on the mount package. http://man7.org/linux/man-pages/man8/swapon.8.html

• swapon -s or swapon --show

swapon --show
NAME      TYPE      SIZE   USED PRIO
/dev/dm-2 partition 976M 974.8M   -2

swapon --show
(No output if not swap active)

• cat /proc/swaps

See also

• Swap, swapon, swapoff, mkswap, swaplabel, free,sar -r, sar -S, sar -W, vmstat, vm.swappiness, /proc/swaps, /etc/fstab, Add a swap disk, systemd.swap
• File systems: mount, umount, findmnt, find, swapon, swapoff, UUID, blkid, mount options: /etc/fstab, udisksctl mount, guestmount, /proc/mounts, fstrim, systemd-mount, defaults
• Memory: memory pages, RAM, virsh Memory Commands, OOM, meminfo, vmstat, NAND, DDR, lsmem, /dev/shm, /proc/meminfo, sar -r, IOMMU, pmem, Memory management, Garbage collector, THP, Linux Huge Page TLB