Subject: Re: [RFC PATCH 10/15] nohz_task: Enter in extended quiescent state
 when in userspace
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>,
        Lai Jiangshan <laijs@cn.fujitsu.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Anton Blanchard <anton@au1.ibm.com>,
        Tim Pepper <lnxninja@linux.vnet.ibm.com>
In-Reply-To: <1292858662-5650-11-git-send-email-fweisbec@gmail.com>
References: <1292858662-5650-1-git-send-email-fweisbec@gmail.com>
	 <1292858662-5650-11-git-send-email-fweisbec@gmail.com>
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Date: Mon, 20 Dec 2010 17:18:40 +0100
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On Mon, 2010-12-20 at 16:24 +0100, Frederic Weisbecker wrote:
> (we check if the local cpu is in nohz mode, which means
> no other task compete on that CPU)

You keep repeating that definition, but its not true.. It means there is
not work for the tick to do, the tick does _tons_ more besides
preemption, so nr_running==1 is necessary but not sufficient. 
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