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bus/arm-ccn: Convert to hotplug statemachine
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Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Anna-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: Ingo Molnar <mingo@kernel.org>
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Sebastian Andrzej Siewior authored and Ingo Molnar committed Jul 14, 2016
1 parent 28c9484 commit fdc15a3
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Showing 2 changed files with 29 additions and 29 deletions.
57 changes: 28 additions & 29 deletions drivers/bus/arm-ccn.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
};
Expand All @@ -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)
{
Expand Down Expand Up @@ -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;
}


Expand Down Expand Up @@ -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);
Expand All @@ -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);
Expand All @@ -1306,17 +1296,19 @@ 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);
perf_pmu_unregister(&ccn->dt.pmu);
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))
Expand Down Expand Up @@ -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;
Expand All @@ -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);
}

Expand Down
1 change: 1 addition & 0 deletions include/linux/cpuhotplug.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down

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