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Subject: Re: [PATCH 05/32] nohz: Move rcu dynticks idle mode handling to
 idle enter/exit APIs
From: Peter Zijlstra <peterz@infradead.org>
To: paulmck@linux.vnet.ibm.com
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>,
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        Stephen Hemminger <shemminger@vyatta.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Tim Pepper <lnxninja@linux.vnet.ibm.com>,
        Paul Menage <paul@paulmenage.org>
Date: Fri, 02 Sep 2011 10:24:31 +0200
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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.