discard option on rootfs

Hello,

Is it safe to add discard as a mount option for the rootfs on the eMMC. I am sometimes writing big chunks of data on the rootfs and it is getting sluggish.

Using debian and Linux arm 3.8.13-bone37 #1 SMP Thu Jan 23 00:56:41 UTC 2014 armv7l GNU/Linux rcn kernels.

Alternatively doing fstrim -v / helps with trim. Gerald, I know that the Micron eMMC supports trim operations I was wondering if it is fully implemented.