Adding SWAP space in ZFS Root filesystem

If you want additional space
# zfs create -V 2G rpool/swap1
# swap -a /dev/zvol/dsk/rpool/swap1
# swap -l

If you want to delete old swap space and add new one

# swap -d /dev/zvol/dsk/rpool/swap
# swap -l (To verify old swap is deleted)
# zfs set volsize=4G rpool/swap
# swap -a /dev/zvol/dsk/rpool/swap
# swap -l