Hi Mike, On Thu, Jul 02, 2015 at 10:05:47AM +0200, Mike Galbraith wrote: > On Thu, 2015-07-02 at 07:25 +0800, Yuyang Du wrote: > > > That being said, it is also obvious to prevent the livelock from happening: > > idle pulling until the source rq's nr_running is 1, becuase otherwise we > > just avoid idleness by making another idleness. > > Yeah, but that's just the symptom, not the disease. Better for the idle > balance symptom may actually be to only pull one when idle balancing. > After all, the immediate goal is to find something better to do than > idle, not to achieve continual perfect (is the enemy of good) balance. > Symptom? :)
You mean "pull one and stop, can't be greedy"? Right, but still need to assure you don't make another idle CPU (meaning until nr_running == 1), which is the cure to disease. I am ok with at most "pull one", but probably we stick to the load_balance() by pulling an fair amount, assuming load_balance() magically computes the right imbalance, otherwise you may have to do multiple "pull one"s. Thanks, Yuyang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
