Enable compcache in ubuntu

Sometimes I'm running a lot of VM? which needs a lot of memory, so i try to enable compcache:

vim /etc/initramfs-tools/initramfs.conf

#Edit this line:
COMPCACHE_SIZE="60 %"

update-initramfs -u
reboot

After enabled, you can see new swap device (ramzswap):

cat /proc/swaps 
Filename    Type  Size Used Priority
/dev/ramzswap0                          partition 1229208 0 100
/dev/sda3                               partition 2064344 0 -1

http://code.google.com/p/compcache/