How to lower OOM value of an app permanently?

I am not challenging Android's memory management technique (like killers do). I just want to give an app higher priority even when it's not in foreground or visible (with notification). *AutoKiller Memory Optimizer* is able to do it on rooted device, but the change lasts for few seconds if I multi-task. I want to do this permanently: perhaps running a background daemon to do change continuously should work. How to do this?