Re: [PATCH?] Livelock in pick_next_task_fair() / idle_balance()

From: Mike Galbraith
Date: Thu Jul 02 2015 - 04:06:11 EST


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.

-Mike

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