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Subject: Re: [patch 09/16] sched: unthrottle cfs_rq(s) who ran out of quota
 at period refresh
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Paul Turner <pjt@google.com>
Cc: linux-kernel@vger.kernel.org, Bharata B Rao <bharata@linux.vnet.ibm.com>,
        Dhaval Giani <dhaval.giani@gmail.com>,
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        Nikhil Rao <ncrao@google.com>
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Date: Tue, 28 Jun 2011 11:11:53 +0200
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On Mon, 2011-06-27 at 21:40 -0700, Paul Turner wrote:
> >> +       if (unlikely(runtime_expires != cfs_b->runtime_expires))
> >> +               goto out_unlock;
> >
> > it might help to explain how, runtime_expires is taken from cfs_b after
> > calling __refill_cfs_bandwidth_runtime, and we're in the replenishment
> > timer, so nobody is going to be adding new runtime.
> >
> 
> Good idea -- thanks 

Aside from being a good idea, I'm genuinely puzzled by that part and
would love having it explained :-)