Commit a49b116d authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

clockevents: Cleanup dead cpu explicitely 



clockevents_notify() is a leftover from the early design of the
clockevents facility. It's really not a notification mechanism,
it's a multiplex call. We are way better off to have explicit
calls instead of this monstrosity.

Split out the cleanup function for a dead cpu and invoke it
directly from the cpu down code. Make it conditional on
CPU_HOTPLUG as well.

Temporary change, will be refined in the future.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
[ Rebased, added clockevents_notify() removal ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1735025.raBZdQHM3m@vostro.rjw.lan


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 52c063d1

include/linux/clockchips.h

+0 −6
Original line number Diff line number Diff line
@@ -8,12 +8,6 @@ 
#ifndef _LINUX_CLOCKCHIPS_H

#define _LINUX_CLOCKCHIPS_H



/* Clock event notification values */

enum clock_event_nofitiers {

	CLOCK_EVT_NOTIFY_ADD,

	CLOCK_EVT_NOTIFY_CPU_DEAD,

};



#ifdef CONFIG_GENERIC_CLOCKEVENTS



# include <linux/clocksource.h>

include/linux/tick.h

+2 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ extern void tick_suspend_local(void); 
/* Should be core only, but XEN resume magic and ARM BL switcher require it */

extern void tick_resume_local(void);

extern void tick_handover_do_timer(void);

extern void tick_cleanup_dead_cpu(int cpu);

#else /* CONFIG_GENERIC_CLOCKEVENTS */

static inline void tick_init(void) { }

static inline void tick_freeze(void) { }
@@ -27,6 +28,7 @@ static inline void tick_unfreeze(void) { } 
static inline void tick_suspend_local(void) { }

static inline void tick_resume_local(void) { }

static inline void tick_handover_do_timer(void) { }

static inline void tick_cleanup_dead_cpu(int cpu) { }

#endif /* !CONFIG_GENERIC_CLOCKEVENTS */



#ifdef CONFIG_TICK_ONESHOT

kernel/cpu.c

+1 −0
Original line number Diff line number Diff line
@@ -419,6 +419,7 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) 
	__cpu_die(cpu);



	/* CPU is completely dead: tell everyone.  Too late to complain. */

	tick_cleanup_dead_cpu(cpu);

	cpu_notify_nofail(CPU_DEAD | mod, hcpu);



	check_for_tasks(cpu);

kernel/time/clockevents.c

+21 −30
Original line number Diff line number Diff line
@@ -642,23 +642,20 @@ void clockevents_resume(void) 
			dev->resume(dev);

}



#ifdef CONFIG_HOTPLUG_CPU

/**

 * clockevents_notify - notification about relevant events

 * Returns 0 on success, any other value on error

 * tick_cleanup_dead_cpu - Cleanup the tick and clockevents of a dead cpu

 */

int clockevents_notify(unsigned long reason, void *arg)

void tick_cleanup_dead_cpu(int cpu)

{

	struct clock_event_device *dev, *tmp;

	unsigned long flags;

	int cpu, ret = 0;



	raw_spin_lock_irqsave(&clockevents_lock, flags);



	switch (reason) {

	case CLOCK_EVT_NOTIFY_CPU_DEAD:

		tick_shutdown_broadcast_oneshot(arg);

		tick_shutdown_broadcast(arg);

		tick_shutdown(arg);

	tick_shutdown_broadcast_oneshot(cpu);

	tick_shutdown_broadcast(cpu);

	tick_shutdown(cpu);

	/*

	 * Unregister the clock event devices which were

	 * released from the users in the notify chain.
@@ -668,7 +665,6 @@ int clockevents_notify(unsigned long reason, void *arg) 
	/*

	 * Now check whether the CPU has left unused per cpu devices

	 */

		cpu = *((int *)arg);

	list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) {

		if (cpumask_test_cpu(cpu, dev->cpumask) &&

		    cpumask_weight(dev->cpumask) == 1 &&
@@ -677,14 +673,9 @@ int clockevents_notify(unsigned long reason, void *arg) 
			list_del(&dev->list);

		}

	}

		break;

	default:

		break;

	}

	raw_spin_unlock_irqrestore(&clockevents_lock, flags);

	return ret;

}

EXPORT_SYMBOL_GPL(clockevents_notify);

#endif



#ifdef CONFIG_SYSFS

struct bus_type clockevents_subsys = {

kernel/time/hrtimer.c

+0 −3
Original line number Diff line number Diff line
@@ -1709,11 +1709,8 @@ static int hrtimer_cpu_notify(struct notifier_block *self, 
#ifdef CONFIG_HOTPLUG_CPU

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

	{

		clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu);

		migrate_hrtimers(scpu);

		break;

	}

#endif



	default:

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