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Commit 14660b7e authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Thomas Gleixner
Browse files

oprofile/nmi timer: Convert to hotplug state machine 



Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: oprofile-list@lists.sf.net
Cc: Robert Richter <rric@kernel.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20161126231350.10321-6-bigeasy@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 9c6bafab

drivers/oprofile/nmi_timer_int.c

+19 −39
Original line number Original line Diff line number Diff line
@@ -59,26 +59,17 @@ static void nmi_timer_stop_cpu(int cpu) 
		perf_event_disable(event);

		perf_event_disable(event);

}

}





static int nmi_timer_cpu_notifier(struct notifier_block *b, unsigned long action,

static int nmi_timer_cpu_online(unsigned int cpu)

				  void *data)

{

{

	int cpu = (unsigned long)data;

	switch (action) {

	case CPU_DOWN_FAILED:

	case CPU_ONLINE:

	nmi_timer_start_cpu(cpu);

	nmi_timer_start_cpu(cpu);

		break;

	return 0;

	case CPU_DOWN_PREPARE:

		nmi_timer_stop_cpu(cpu);

		break;

}

}

	return NOTIFY_DONE;

static int nmi_timer_cpu_predown(unsigned int cpu)

{

	nmi_timer_stop_cpu(cpu);

	return 0;

}

}





static struct notifier_block nmi_timer_cpu_nb = {

	.notifier_call = nmi_timer_cpu_notifier

};



static int nmi_timer_start(void)

static int nmi_timer_start(void)

{

{

	int cpu;

	int cpu;
@@ -103,13 +94,14 @@ static void nmi_timer_stop(void) 
	put_online_cpus();

	put_online_cpus();

}

}





static enum cpuhp_state hp_online;



static void nmi_timer_shutdown(void)

static void nmi_timer_shutdown(void)

{

{

	struct perf_event *event;

	struct perf_event *event;

	int cpu;

	int cpu;





	cpu_notifier_register_begin();

	cpuhp_remove_state(hp_online);

	__unregister_cpu_notifier(&nmi_timer_cpu_nb);

	for_each_possible_cpu(cpu) {

	for_each_possible_cpu(cpu) {

		event = per_cpu(nmi_timer_events, cpu);

		event = per_cpu(nmi_timer_events, cpu);

		if (!event)

		if (!event)
@@ -118,13 +110,11 @@ static void nmi_timer_shutdown(void) 
		per_cpu(nmi_timer_events, cpu) = NULL;

		per_cpu(nmi_timer_events, cpu) = NULL;

		perf_event_release_kernel(event);

		perf_event_release_kernel(event);

	}

	}



	cpu_notifier_register_done();

}

}





static int nmi_timer_setup(void)

static int nmi_timer_setup(void)

{

{

	int cpu, err;

	int err;

	u64 period;

	u64 period;





	/* clock cycles per tick: */

	/* clock cycles per tick: */
@@ -132,24 +122,14 @@ static int nmi_timer_setup(void) 
	do_div(period, HZ);

	do_div(period, HZ);

	nmi_timer_attr.sample_period = period;

	nmi_timer_attr.sample_period = period;





	cpu_notifier_register_begin();

	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "oprofile/nmi:online",

	err = __register_cpu_notifier(&nmi_timer_cpu_nb);

				nmi_timer_cpu_online, nmi_timer_cpu_predown);

	if (err)

	if (err < 0) {

		goto out;



	/* can't attach events to offline cpus: */

	for_each_online_cpu(cpu) {

		err = nmi_timer_start_cpu(cpu);

		if (err) {

			cpu_notifier_register_done();

		nmi_timer_shutdown();

		nmi_timer_shutdown();

		return err;

		return err;

	}

	}

	}

	hp_online = err;



	return 0;

out:

	cpu_notifier_register_done();

	return err;

}

}





int __init op_nmi_timer_init(struct oprofile_operations *ops)

int __init op_nmi_timer_init(struct oprofile_operations *ops)