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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>, Alan Cox <alan@linux.intel.com>,
        "Li, Aubrey" <aubrey.li@linux.intel.com>,
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        Linux PM list <linux-pm@vger.kernel.org>,
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        Kristen Carlson Accardi <kristen@linux.intel.com>,
        John Stultz <john.stultz@linaro.org>, Len Brown <len.brown@intel.com>
Subject: Re: [PATCH 1/6] PM / sleep: Re-implement suspend-to-idle handling
Date: Thu, 12 Feb 2015 17:18 +0100
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On Thursday, February 12, 2015 02:14:20 PM Peter Zijlstra wrote:
> On Wed, Feb 11, 2015 at 05:01:09AM +0100, Rafael J. Wysocki wrote:
> > +/* Suspend-to-idle state machnine. */
> > +enum freeze_state {
> > +	FREEZE_STATE_NONE,      /* Not suspended/suspending. */
> > +	FREEZE_STATE_ENTER,     /* Enter suspend-to-idle. */
> > +	FREEZE_STATE_WAKE,      /* Wake up from suspend-to-idle. */
> > +};
> > +
> > +static enum freeze_state __read_mostly suspend_freeze_state;
> > +static DEFINE_SPINLOCK(suspend_freeze_lock);
> > +
> > +bool idle_should_freeze(void)
> > +{
> > +	return unlikely(suspend_freeze_state == FREEZE_STATE_ENTER);
> > +}
> 
> I don't see how a compiler can propagate the unlikely through an actual
> function call. AFAICT that needs to be an inline function for that to
> work.

Oh.

That was silly, I'll send an update later today.

> It would mean exposing suspend_freeze_state and the enum; is there a
> reason not to want to do that?

Not really.