Swappiness doesn't work as expected

Hi,

you can fin below an extract of what I have on my droplet (Ubuntu 14.04.5 LTS):

System information as of Sat Apr 11 04:50:46 EDT 2015

System load: 0.01 Processes: 89 Usage of /: 62.2% of 19.56GB Users logged in: 0 Memory usage: 68% IP address for eth0: 178.62.7.107 Swap usage: 0%

root@droplet1:~# free -m total used free
Mem: 993 834 158
-/+ buffers/cache: 668 324 Swap: 4095 0 4095 root@droplet1:~# cat /proc/sys/vm/swappiness 90

So normally, by setting up swappiness to 90, I should have the swap used as soon as more than 10% of my RAM is used, but it is not the case, someone already ran into that problem with DO? on my other stations it works good.