linux-kernel - Re: [patch 6/6] x86: add c1e aware idle function

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Message-ID: <alpine.LFD.1.10.0806130800060.3193@apollo.tec.linutronix.de>
Date:	Fri, 13 Jun 2008 08:02:30 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Andrew Morton <akpm@...ux-foundation.org>
cc:	linux-kernel@...r.kernel.org, mingo@...e.hu, arjan@...radead.org,
	andreas.herrmann3@....com
Subject: Re: [patch 6/6] x86: add c1e aware idle function

On Thu, 12 Jun 2008, Andrew Morton wrote:
> On Thu, 12 Jun 2008 10:29:00 -0000
> Thomas Gleixner <tglx@...utronix.de> wrote:
> > +		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
> > +		default_idle();
> > +		local_irq_disable();
> > +		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
> > +		local_irq_enable();
> 
> I worked it out!  It took me a while.
> 
> This function is called with local irqs disabled.
> 
> default_idle() is entered with local irqs disabled but returns with them
> enabled.
> 
> clockevents_notify() is supposed to be called with local irqs disabled.
> 
> This functions returns with local irqs enabled.

Damn, you decoded my sekrit.
 
> Was I right?  None of any of that is documented anywhere.  But it should
> be.

Yeah, needs a big comment. Will add one.

Thanks,

	tglx
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