why after swap increasing and swapoff and swapon , swap total return to the previous value
You should check "/etc/fstab" file first whether there is swap partition entry there or not. "swapon -a" command will check the swap partition entry from "/etc/fstab" and assign swap memory from that partition. You can add line below in fstab.
/dev/mapper/rootvg-swap1 none swap sw 0 0
Than try "swapon -a" command.