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Commit 45cb8e01 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

clockevents: Split out selection logic 



Split out the clockevent device selection logic. Preparatory patch to
allow unbinding active clockevent devices.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130425143436.431796247@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 501f8670

kernel/time/tick-broadcast.c

+20 −5
Original line number Diff line number Diff line
@@ -65,19 +65,34 @@ static void tick_broadcast_start_periodic(struct clock_event_device *bc) 
/*

 * Check, if the device can be utilized as broadcast device:

 */

static bool tick_check_broadcast_device(struct clock_event_device *curdev,

					struct clock_event_device *newdev)

{

	if ((newdev->features & CLOCK_EVT_FEAT_DUMMY) ||

	    (newdev->features & CLOCK_EVT_FEAT_C3STOP))

		return false;



	if (tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT &&

	    !(newdev->features & CLOCK_EVT_FEAT_ONESHOT))

		return false;



	return !curdev || newdev->rating > curdev->rating;

}



/*

 * Conditionally install/replace broadcast device

 */

void tick_install_broadcast_device(struct clock_event_device *dev)

{

	struct clock_event_device *cur = tick_broadcast_device.evtdev;



	if ((dev->features & CLOCK_EVT_FEAT_DUMMY) ||

	    (tick_broadcast_device.evtdev &&

	     tick_broadcast_device.evtdev->rating >= dev->rating) ||

	     (dev->features & CLOCK_EVT_FEAT_C3STOP))

	if (!tick_check_broadcast_device(cur, dev))

		return;



	if (!try_module_get(dev->owner))

		return;



	clockevents_exchange_device(tick_broadcast_device.evtdev, dev);

	clockevents_exchange_device(cur, dev);

	if (cur)

		cur->event_handler = clockevents_handle_noop;

	tick_broadcast_device.evtdev = dev;

kernel/time/tick-common.c

+36 −33
Original line number Diff line number Diff line
@@ -205,6 +205,37 @@ static void tick_setup_device(struct tick_device *td, 
		tick_setup_oneshot(newdev, handler, next_event);

}



static bool tick_check_percpu(struct clock_event_device *curdev,

			      struct clock_event_device *newdev, int cpu)

{

	if (!cpumask_test_cpu(cpu, newdev->cpumask))

		return false;

	if (cpumask_equal(newdev->cpumask, cpumask_of(cpu)))

		return true;

	/* Check if irq affinity can be set */

	if (newdev->irq >= 0 && !irq_can_set_affinity(newdev->irq))

		return false;

	/* Prefer an existing cpu local device */

	if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu)))

		return false;

	return true;

}



static bool tick_check_preferred(struct clock_event_device *curdev,

				 struct clock_event_device *newdev)

{

	/* Prefer oneshot capable device */

	if (!(newdev->features & CLOCK_EVT_FEAT_ONESHOT)) {

		if (curdev && (curdev->features & CLOCK_EVT_FEAT_ONESHOT))

			return false;

		if (tick_oneshot_mode_active())

			return false;

	}



	/* Use the higher rated one */

	return !curdev || newdev->rating > curdev->rating;

}



/*

 * Check, if the new registered device should be used. Called with

 * clockevents_lock held and interrupts disabled.
@@ -223,40 +254,12 @@ void tick_check_new_device(struct clock_event_device *newdev) 
	curdev = td->evtdev;



	/* cpu local device ? */

	if (!cpumask_equal(newdev->cpumask, cpumask_of(cpu))) {



		/*

		 * If the cpu affinity of the device interrupt can not

		 * be set, ignore it.

		 */

		if (!irq_can_set_affinity(newdev->irq))

	if (!tick_check_percpu(curdev, newdev, cpu))

		goto out_bc;



		/*

		 * If we have a cpu local device already, do not replace it

		 * by a non cpu local device

		 */

		if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu)))

	/* Preference decision */

	if (!tick_check_preferred(curdev, newdev))

		goto out_bc;

	}



	/*

	 * If we have an active device, then check the rating and the oneshot

	 * feature.

	 */

	if (curdev) {

		/*

		 * Prefer one shot capable devices !

		 */

		if ((curdev->features & CLOCK_EVT_FEAT_ONESHOT) &&

		    !(newdev->features & CLOCK_EVT_FEAT_ONESHOT))

			goto out_bc;

		/*

		 * Check the rating

		 */

		if (curdev->rating >= newdev->rating)

			goto out_bc;

	}



	if (!try_module_get(newdev->owner))

		return;