[gentoo-user] SSD discard / fstrim

[Joseph]

This is my first SSD drive 480GB (the only one in the box).  I read about all discard / trim option and just want to double check that I'm doing it correct.

I setup standard Gentoo and per instruction in Handbook.
Not I'm reading about discard 
http://wiki.gentoo.org/wiki/SSD

Do I setup: fstrim -v / 
or discard in fstab:
/dev/sda2               /boot           ext2            noauto,noatime  1 2
/dev/sda4               /               ext4            defaults,relatime,discard       0 1
/dev/sda3               none            swap            sw,pri=3,discard                0 0

Can I use them both?
Do I need to add "discard" to /boot?


-- 
Joseph