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Commit fdc15a36 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Ingo Molnar
Browse files

bus/arm-ccn: Convert to hotplug statemachine 



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>
Signed-off-by: default avatarAnna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153334.768498577@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 28c94843

drivers/bus/arm-ccn.c

+28 −29
Original line number Diff line number Diff line
@@ -167,7 +167,7 @@ struct arm_ccn_dt { 
	struct hrtimer hrtimer;



	cpumask_t cpu;

	struct notifier_block cpu_nb;

	struct list_head entry;



	struct pmu pmu;

};
@@ -189,6 +189,8 @@ struct arm_ccn { 
	struct arm_ccn_dt dt;

};



static DEFINE_MUTEX(arm_ccn_mutex);

static LIST_HEAD(arm_ccn_list);



static int arm_ccn_node_to_xp(int node)

{
@@ -1171,30 +1173,27 @@ static enum hrtimer_restart arm_ccn_pmu_timer_handler(struct hrtimer *hrtimer) 
}





static int arm_ccn_pmu_cpu_notifier(struct notifier_block *nb,

		unsigned long action, void *hcpu)

static int arm_ccn_pmu_offline_cpu(unsigned int cpu)

{

	struct arm_ccn_dt *dt = container_of(nb, struct arm_ccn_dt, cpu_nb);

	struct arm_ccn *ccn = container_of(dt, struct arm_ccn, dt);

	unsigned int cpu = (long)hcpu; /* for (long) see kernel/cpu.c */

	struct arm_ccn_dt *dt;

	unsigned int target;



	switch (action & ~CPU_TASKS_FROZEN) {

	case CPU_DOWN_PREPARE:

	mutex_lock(&arm_ccn_mutex);

	list_for_each_entry(dt, &arm_ccn_list, entry) {

		struct arm_ccn *ccn = container_of(dt, struct arm_ccn, dt);



		if (!cpumask_test_and_clear_cpu(cpu, &dt->cpu))

			break;

			continue;

		target = cpumask_any_but(cpu_online_mask, cpu);

		if (target >= nr_cpu_ids)

			break;

			continue;

		perf_pmu_migrate_context(&dt->pmu, cpu, target);

		cpumask_set_cpu(target, &dt->cpu);

		if (ccn->irq)

			WARN_ON(irq_set_affinity_hint(ccn->irq, &dt->cpu) != 0);

	default:

		break;

	}



	return NOTIFY_OK;

	mutex_unlock(&arm_ccn_mutex);

	return 0;

}
@@ -1266,16 +1265,6 @@ static int arm_ccn_pmu_init(struct arm_ccn *ccn) 
	/* Pick one CPU which we will use to collect data from CCN... */

	cpumask_set_cpu(smp_processor_id(), &ccn->dt.cpu);



	/*

	 * ... and change the selection when it goes offline. Priority is

	 * picked to have a chance to migrate events before perf is notified.

	 */

	ccn->dt.cpu_nb.notifier_call = arm_ccn_pmu_cpu_notifier;

	ccn->dt.cpu_nb.priority = CPU_PRI_PERF + 1,

	err = register_cpu_notifier(&ccn->dt.cpu_nb);

	if (err)

		goto error_cpu_notifier;



	/* Also make sure that the overflow interrupt is handled by this CPU */

	if (ccn->irq) {

		err = irq_set_affinity_hint(ccn->irq, &ccn->dt.cpu);
@@ -1289,12 +1278,13 @@ static int arm_ccn_pmu_init(struct arm_ccn *ccn) 
	if (err)

		goto error_pmu_register;



	mutex_lock(&arm_ccn_mutex);

	list_add(&ccn->dt.entry, &arm_ccn_list);

	mutex_unlock(&arm_ccn_mutex);

	return 0;



error_pmu_register:

error_set_affinity:

	unregister_cpu_notifier(&ccn->dt.cpu_nb);

error_cpu_notifier:

	ida_simple_remove(&arm_ccn_pmu_ida, ccn->dt.id);

	for (i = 0; i < ccn->num_xps; i++)

		writel(0, ccn->xp[i].base + CCN_XP_DT_CONTROL);
@@ -1306,9 +1296,12 @@ static void arm_ccn_pmu_cleanup(struct arm_ccn *ccn) 
{

	int i;



	mutex_lock(&arm_ccn_mutex);

	list_del(&ccn->dt.entry);

	mutex_unlock(&arm_ccn_mutex);



	if (ccn->irq)

		irq_set_affinity_hint(ccn->irq, NULL);

	unregister_cpu_notifier(&ccn->dt.cpu_nb);

	for (i = 0; i < ccn->num_xps; i++)

		writel(0, ccn->xp[i].base + CCN_XP_DT_CONTROL);

	writel(0, ccn->dt.base + CCN_DT_PMCR);
@@ -1316,7 +1309,6 @@ static void arm_ccn_pmu_cleanup(struct arm_ccn *ccn) 
	ida_simple_remove(&arm_ccn_pmu_ida, ccn->dt.id);

}





static int arm_ccn_for_each_valid_region(struct arm_ccn *ccn,

		int (*callback)(struct arm_ccn *ccn, int region,

		void __iomem *base, u32 type, u32 id))
@@ -1533,7 +1525,13 @@ static struct platform_driver arm_ccn_driver = { 


static int __init arm_ccn_init(void)

{

	int i;

	int i, ret;



	ret = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ARM_CCN_ONLINE,

					"AP_PERF_ARM_CCN_ONLINE", NULL,

					arm_ccn_pmu_offline_cpu);

	if (ret)

		return ret;



	for (i = 0; i < ARRAY_SIZE(arm_ccn_pmu_events); i++)

		arm_ccn_pmu_events_attrs[i] = &arm_ccn_pmu_events[i].attr.attr;
@@ -1543,6 +1541,7 @@ static int __init arm_ccn_init(void) 


static void __exit arm_ccn_exit(void)

{

	cpuhp_remove_state_nocalls(CPUHP_AP_PERF_ARM_CCN_ONLINE);

	platform_driver_unregister(&arm_ccn_driver);

}

include/linux/cpuhotplug.h

+1 −0
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ enum cpuhp_state { 
	CPUHP_AP_PERF_S390_CF_ONLINE,

	CPUHP_AP_PERF_S390_SF_ONLINE,

	CPUHP_AP_PERF_ARM_CCI_ONLINE,

	CPUHP_AP_PERF_ARM_CCN_ONLINE,

	CPUHP_AP_NOTIFY_ONLINE,

	CPUHP_AP_ONLINE_DYN,

	CPUHP_AP_ONLINE_DYN_END		= CPUHP_AP_ONLINE_DYN + 30,