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Commit 27590dc1 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

hrtimer: Convert to hotplug state machine 



Split out the clockevents callbacks instead of piggybacking them on
hrtimers.

This gets rid of a POST_DEAD user. See commit:

  54e88fad ("sched: Make sure timers have migrated before killing the migration_thread")

We just move the callback state to the proper place in the state machine.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarAnna-Maria Gleixner <anna-maria@linutronix.de>
Reviewed-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153337.485419196@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent ae6a8a2e

include/linux/cpuhotplug.h

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ enum cpuhp_state { 
	CPUHP_X86_HPET_DEAD,

	CPUHP_X86_APB_DEAD,

	CPUHP_WORKQUEUE_PREP,

	CPUHP_HRTIMERS_PREPARE,

	CPUHP_NOTIFY_PREPARE,

	CPUHP_BRINGUP_CPU,

	CPUHP_AP_IDLE_DEAD,

include/linux/hrtimer.h

+7 −0
Original line number Diff line number Diff line
@@ -494,4 +494,11 @@ extern void __init hrtimers_init(void); 
/* Show pending timers: */

extern void sysrq_timer_list_show(void);



int hrtimers_prepare_cpu(unsigned int cpu);

#ifdef CONFIG_HOTPLUG_CPU

int hrtimers_dead_cpu(unsigned int cpu);

#else

#define hrtimers_dead_cpu	NULL

#endif



#endif

kernel/cpu.c

+5 −0
Original line number Diff line number Diff line
@@ -1190,6 +1190,11 @@ static struct cpuhp_step cpuhp_bp_states[] = { 
		.startup = workqueue_prepare_cpu,

		.teardown = NULL,

	},

	[CPUHP_HRTIMERS_PREPARE] = {

		.name = "hrtimers prepare",

		.startup = hrtimers_prepare_cpu,

		.teardown = hrtimers_dead_cpu,

	},

	/*

	 * Preparatory and dead notifiers. Will be replaced once the notifiers

	 * are converted to states.

kernel/time/hrtimer.c

+5 −35
Original line number Diff line number Diff line
@@ -1590,7 +1590,7 @@ SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp, 
/*

 * Functions related to boot-time initialization:

 */

static void init_hrtimers_cpu(int cpu)

int hrtimers_prepare_cpu(unsigned int cpu)

{

	struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);

	int i;
@@ -1602,6 +1602,7 @@ static void init_hrtimers_cpu(int cpu) 


	cpu_base->cpu = cpu;

	hrtimer_init_hres(cpu_base);

	return 0;

}



#ifdef CONFIG_HOTPLUG_CPU
@@ -1636,7 +1637,7 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base, 
	}

}



static void migrate_hrtimers(int scpu)

int hrtimers_dead_cpu(unsigned int scpu)

{

	struct hrtimer_cpu_base *old_base, *new_base;

	int i;
@@ -1665,45 +1666,14 @@ static void migrate_hrtimers(int scpu) 
	/* Check, if we got expired work to do */

	__hrtimer_peek_ahead_timers();

	local_irq_enable();

	return 0;

}



#endif /* CONFIG_HOTPLUG_CPU */



static int hrtimer_cpu_notify(struct notifier_block *self,

					unsigned long action, void *hcpu)

{

	int scpu = (long)hcpu;



	switch (action) {



	case CPU_UP_PREPARE:

	case CPU_UP_PREPARE_FROZEN:

		init_hrtimers_cpu(scpu);

		break;



#ifdef CONFIG_HOTPLUG_CPU

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

		migrate_hrtimers(scpu);

		break;

#endif



	default:

		break;

	}



	return NOTIFY_OK;

}



static struct notifier_block hrtimers_nb = {

	.notifier_call = hrtimer_cpu_notify,

};



void __init hrtimers_init(void)

{

	hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,

			  (void *)(long)smp_processor_id());

	register_cpu_notifier(&hrtimers_nb);

	hrtimers_prepare_cpu(smp_processor_id());

}



/**