Re: [patch 15/16] sched: return unused runtime on voluntary sleep

Peter Zijlstra
2011-06-28T10:05:59Z

On Mon, 2011-06-27 at 18:42 -0700, Paul Turner wrote:

> - The aesthetics of releasing rq->lock in the put path. Quick
> inspection suggests it should actually be safe to do at that point,
> and we do similar for idle_balance().
>
> Given consideration the above two factors are not requirements, this
> could be moved out of a timer and into the put_path directly (with the
> fact that we drop rq->lock strongly commented). I have no strong
> preference between either choice.

Argh, ok I see, distribute_cfs_runtime() wants that. Dropping rq->lock
is very fragile esp from the put path, you can only do that _before_ the
put path updates rq->curr etc.. So I'd rather you didn't, just keep the
timer crap and add some comments there.

And we need that distribute_cfs_runtime() muck because that's what
unthrottles rqs when more runtime is available.. bah.