Messages in this thread | | | Subject | Re: [RFC PATCH 07/15] nohz_task: Restart tick when RCU forces nohz task cpu quiescent state | From | Peter Zijlstra <> | Date | Tue, 21 Dec 2010 08:41:14 +0100 |
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On Tue, 2010-12-21 at 00:52 +0100, Frederic Weisbecker wrote: > 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.
That still doesn't make sense.. if you're in nohz state there shouldn't be any rcu activity, otherwise its not nohz is it?
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