linux-kernel - Re: [Update] Re: [PATCH v3]PM/Sleep: Timer quiesce in freeze state

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Message-ID: <20150206161454.GQ21418@twins.programming.kicks-ass.net>
Date:	Fri, 6 Feb 2015 17:14:54 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	"Li, Aubrey" <aubrey.li@...ux.intel.com>,
	"Brown, Len" <len.brown@...el.com>,
	Alan Cox <alan@...ux.intel.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux PM list <linux-pm@...r.kernel.org>
Subject: Re: [Update] Re: [PATCH v3]PM/Sleep: Timer quiesce in freeze state

On Fri, Feb 06, 2015 at 02:20:13AM +0100, Rafael J. Wysocki wrote:
>  void freeze_wake(void)
>  {
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&suspend_freeze_lock, flags);
> +	if (suspend_freeze_state > FREEZE_STATE_NONE) {
> +		suspend_freeze_state = FREEZE_STATE_WAKE;
> +		wake_up(&suspend_freeze_wait_head);
> +	}
> +	spin_unlock_irqrestore(&suspend_freeze_lock, flags);
>  }


> +static void enter_freeze_proper(struct cpuidle_driver *drv,
> +				struct cpuidle_device *dev, int index)
> +{
> +	tick_freeze();
> +	drv->states[index].enter_freeze(dev, drv, index);
> +	/*
> +	 * timekeeping_resume() that will be called by tick_unfreeze() for the
> +	 * last CPU executing it calls functions containing RCU read-side
> +	 * critical sections, so tell RCU about that.
> +	 */
> +	RCU_NONIDLE(tick_unfreeze());
> +}

So I'm a wee bit confused; if we use an enter_freeze() state that keeps
interrupts disabled; who is going to call the freeze_wake() thing?
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