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[PATCH] tick-management: broadcast functionality

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With Ingo Molnar <mingo@elte.hu>

Add broadcast functionality, so per cpu clock event devices can be registered
as dummy devices or switched from/to broadcast on demand.  The broadcast
function distributes the events via the broadcast function of the clock event
device.  This is primarily designed to replace the switch apic timer to / from
IPI in power states, where the apic stops.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Thomas Gleixner
2007-02-16 01:28:02 -08:00
committed by Linus Torvalds
parent 906568c9c6
commit f8381cba04
4 changed files with 382 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

53
kernel/time/tick-common.c
View File

@@ -20,17 +20,19 @@
#include <linux/sched.h>
#include <linux/tick.h>
#include "tick-internal.h"
/*
* Tick devices
*/
static DEFINE_PER_CPU(struct tick_device, tick_cpu_device);
DEFINE_PER_CPU(struct tick_device, tick_cpu_device);
/*
* Tick next event: keeps track of the tick time
*/
static ktime_t tick_next_period;
static ktime_t tick_period;
ktime_t tick_next_period;
ktime_t tick_period;
static int tick_do_timer_cpu = -1;
static DEFINE_SPINLOCK(tick_device_lock);
DEFINE_SPINLOCK(tick_device_lock);
/*
* Periodic tick
@@ -78,9 +80,13 @@ void tick_handle_periodic(struct clock_event_device *dev)
/*
* Setup the device for a periodic tick
*/
void tick_setup_periodic(struct clock_event_device *dev)
void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
{
dev->event_handler = tick_handle_periodic;
tick_set_periodic_handler(dev, broadcast);
/* Broadcast setup ? */
if (!tick_device_is_functional(dev))
return;
if (dev->features & CLOCK_EVT_FEAT_PERIODIC) {
clockevents_set_mode(dev, CLOCK_EVT_MODE_PERIODIC);
@@ -145,6 +151,15 @@ static void tick_setup_device(struct tick_device *td,
if (!cpus_equal(newdev->cpumask, cpumask))
irq_set_affinity(newdev->irq, cpumask);
/*
* When global broadcasting is active, check if the current
* device is registered as a placeholder for broadcast mode.
* This allows us to handle this x86 misfeature in a generic
* way.
*/
if (tick_device_uses_broadcast(newdev, cpu))
return;
if (td->mode == TICKDEV_MODE_PERIODIC)
tick_setup_periodic(newdev, 0);
}
@@ -197,19 +212,33 @@ static int tick_check_new_device(struct clock_event_device *newdev)
* Check the rating
*/
if (curdev->rating >= newdev->rating)
goto out;
goto out_bc;
}
/*
* Replace the eventually existing device by the new
* device.
* device. If the current device is the broadcast device, do
* not give it back to the clockevents layer !
*/
if (tick_is_broadcast_device(curdev)) {
clockevents_set_mode(curdev, CLOCK_EVT_MODE_SHUTDOWN);
curdev = NULL;
}
clockevents_exchange_device(curdev, newdev);
tick_setup_device(td, newdev, cpu, cpumask);
ret = NOTIFY_STOP;
spin_unlock_irqrestore(&tick_device_lock, flags);
return NOTIFY_STOP;
out_bc:
/*
* Can the new device be used as a broadcast device ?
*/
if (tick_check_broadcast_device(newdev))
ret = NOTIFY_STOP;
out:
spin_unlock_irqrestore(&tick_device_lock, flags);
return ret;
}
@@ -251,7 +280,13 @@ static int tick_notify(struct notifier_block *nb, unsigned long reason,
case CLOCK_EVT_NOTIFY_ADD:
return tick_check_new_device(dev);
case CLOCK_EVT_NOTIFY_BROADCAST_ON:
case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
tick_broadcast_on_off(reason, dev);
break;
case CLOCK_EVT_NOTIFY_CPU_DEAD:
tick_shutdown_broadcast(dev);
tick_shutdown(dev);
break;