Hello,
I've installed Kali Linux a few days ago, choosing the option that installs the OS with different partitions for "/", "var", "tmp", "home" and "swap".
Now, my hard disk (320 Gb) is divided as follows:

/home: 283 Gb
/tmp: 380 Mb
/var: 2.80 Gb
/: 8 Gb (only 800 Mb of free space)

Is it possible that the root partition is so small? Everytime I turn on my computer, the system shows me an alert and says the free space on the root partition is coming to finish.

(I've also tried to edit the size of the root partition but Gparted doesn't work in this case, because it's impossible to unmount the root partition).

Is there a solution for this problem?
(sorry for my bad english, I am Italian)