Re: [RFC PATCH 07/15] nohz_task: Restart tick when RCU forces nohztask cpu quiescent state

[Frederic Weisbecker]

On Mon, Dec 20, 2010 at 05:02:09PM +0100, Peter Zijlstra wrote:
> On Mon, 2010-12-20 at 16:24 +0100, Frederic Weisbecker wrote:
> > If a cpu is in nohz mode due to a nohz task running, then
> > it is not able to notify quiescent states requested by other
> > CPUs.
> > 
> > Then restart the tick to remotely force the quiescent states on the
> > nohz task cpus.
> 
> -ENOPARSE.. if its in NOHZ state, it couldn't possibly need to
> participate in the quiescent state machine because the cpu is in a
> quiescent state and has 0 RCU activity.


But it can be in nohz state in the kernel in which case it can have
any RCU activity.
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