Need to be careful with those commands. It made my install crash

1. Determine the name of the swap logical volume using the "lvs" command:

$ lvs
LV VG Attr LSize Origin Snap% Move Log Copy%
root_lv volgroup0 -wi-ao 7.00G
swap_lv1 volgroup0 -wi-ao 30.00G
tmp_lv volgroup0 -wi-ao 3.00G
usr_lv volgroup0 -wi-ao 7.00G
var_lv volgroup0 -wi-ao 4.00G

1. Turn off the swap partition:

$ swapoff /dev/volgroup0/swap_lv1

1. Resize the swap partition, adding 15GB more space to it:

$ lvresize -L+15G /dev/volgroup0/swap_lv1
Extending logical volume swap_lv1 to 30.00 GB
Logical volume swap_lv1 successfully resized

1. Format the new swap space to make it usable:

$ mkswap /dev/volgroup0/swap_lv1
Setting up swapspace version 1, size = 41875927 kB

1. Turn the swap volume back on:

$ swapon /dev/volgroup0/swap_lv1

1. Use free command to show your new swap space:

$ free -t | grep -i swap
Swap: 30719 0 30719

Source: https://askubuntu.com/questions/226520/how-can-i-modify-the-size-of-swap-with-lvm-partitions