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Date: Sun, 4 Sep 2011 12:37:03 -0700
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Anton Blanchard <anton@au1.ibm.com>, Avi Kivity <avi@redhat.com>,
        Ingo Molnar <mingo@elte.hu>, Lai Jiangshan <laijs@cn.fujitsu.com>,
        Stephen Hemminger <shemminger@vyatta.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Tim Pepper <lnxninja@linux.vnet.ibm.com>,
        Paul Menage <paul@paulmenage.org>
Subject: Re: [PATCH 05/32] nohz: Move rcu dynticks idle mode handling to
 idle enter/exit APIs
Message-ID: <20110904193703.GA9775@linux.vnet.ibm.com>
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On Fri, Sep 02, 2011 at 10:24:31AM +0200, Peter Zijlstra wrote:
> On Thu, 2011-09-01 at 18:41 -0700, Paul E. McKenney wrote:
> > > Now we could possibly add magic to rcu_read_unlock_special() to restart
> > > the tick in that case.
> > 
> > Not from NMI handlers we can't.  Unless I am really confused about the
> > code that restarts the tick.  Which is not impossible, but ... 
> 
> Uhm.. good point ;-) yes that will be somewhat detrimental to the
> overall OS health if we attempt such a thing.

But if you don't mind, I would very much like to use your question as
a Quick Quiz.  It should be a good one.  ;-)

							Thanx, Paul