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Date: Wed, 11 Dec 2013 16:09:11 +0100
From: Ingo Molnar <mingo@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
        Mike Galbraith <bitbucket@online.de>, Borislav Petkov <bp@alien8.de>,
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        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Jeremy Eder <jeder@redhat.com>, x86@kernel.org
Subject: Re: 50 Watt idle power regression bisected to Linux-3.10
Message-ID: <20131211150911.GA11048@gmail.com>
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* Thomas Gleixner <tglx@linutronix.de> wrote:

> On Wed, 11 Dec 2013, Ingo Molnar wrote:
> > 
> > Another thing that is required I think is to issue a write barrier 
> > before CLFLUSH instruction. By my (possibly incorrect ...) reading of 
> > the documentation CLFLUSH does not appear to be ordered (at all), so 
> > it might execute before the modification to the affected memory?
> 
> We already have a write barrier in the code which modifies
> current_thread_info()->flags.

Which code is that, could you please cite it? (I tried finding it but 
my grep-fu failed me.)

Thanks,

	Ingo