Subject: Re: [RFC PATCH 15/15] nohz_task: Procfs interface
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>
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Date: Tue, 21 Dec 2010 09:14:40 +0100
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On Tue, 2010-12-21 at 02:24 +0100, Frederic Weisbecker wrote:
> 
> > Also, I'm not quite happy with the pure userspace restriction, but at
> > least I see why you did that event though you didn't mention that.
> 
> What do you mean? The fact that kernel threads can not be nohz task? 

No, that you key off kernel/user boundary transitions. Arguably one
could allow simply system calls and page-faults to happen without
restarting the tick, then again, RCU is very pervasive these days so I'm
not quite sure you can actually make that happen.


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