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perf/arm-cci: Simplify CPU hotplug

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Realistically, systems with multiple CCIs are unlikely to ever exist,
and since the driver only actually supports a single instance anyway
there's really no need to do the multi-instance hotplug state dance.

Take the opportunity to simplify the hotplug-related code all over,
addressing the context-migration TODO in the process for good measure.

Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Robin Murphy 2018-02-15 18:51:43 +00:00 committed by Arnd Bergmann
parent 3de6be7a3d
commit 03057f2626
1 changed files with 19 additions and 37 deletions
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56
drivers/perf/arm-cci.c
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@ -90,6 +90,7 @@ static struct cci_pmu_model cci_pmu_models[];
struct cci_pmu {
void __iomem *base;
struct pmu pmu;
int cpu;
int nr_irqs;
int *irqs;
unsigned long active_irqs;
@ -99,12 +100,12 @@ struct cci_pmu {
int num_cntrs;
atomic_t active_events;
struct mutex reserve_mutex;
struct hlist_node node;
cpumask_t cpus;
};
#define to_cci_pmu(c) (container_of(c, struct cci_pmu, pmu))
static struct cci_pmu *g_cci_pmu;
enum cci_models {
#ifdef CONFIG_ARM_CCI400_PMU
CCI400_R0,
@ -1325,7 +1326,6 @@ static int cci_pmu_event_init(struct perf_event *event)
struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
atomic_t *active_events = &cci_pmu->active_events;
int err = 0;
int cpu;
if (event->attr.type != event->pmu->type)
return -ENOENT;
@ -1352,10 +1352,9 @@ static int cci_pmu_event_init(struct perf_event *event)
* the event being installed into its context, so the PMU's CPU can't
* change under our feet.
*/
cpu = cpumask_first(&cci_pmu->cpus);
if (event->cpu < 0 || cpu < 0)
if (event->cpu < 0)
return -EINVAL;
event->cpu = cpu;
event->cpu = cci_pmu->cpu;
event->destroy = hw_perf_event_destroy;
if (!atomic_inc_not_zero(active_events)) {
@ -1382,11 +1381,7 @@ static ssize_t pmu_cpumask_attr_show(struct device *dev,
struct pmu *pmu = dev_get_drvdata(dev);
struct cci_pmu *cci_pmu = to_cci_pmu(pmu);
int n = scnprintf(buf, PAGE_SIZE - 1, "%*pbl",
cpumask_pr_args(&cci_pmu->cpus));
buf[n++] = '\n';
buf[n] = '\0';
return n;
return cpumap_print_to_pagebuf(true, buf, cpumask_of(cci_pmu->cpu));
}
static struct device_attribute pmu_cpumask_attr =
@ -1455,21 +1450,19 @@ static int cci_pmu_init(struct cci_pmu *cci_pmu, struct platform_device *pdev)
return perf_pmu_register(&cci_pmu->pmu, name, -1);
}
static int cci_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
static int cci_pmu_offline_cpu(unsigned int cpu)
{
struct cci_pmu *cci_pmu = hlist_entry_safe(node, struct cci_pmu, node);
unsigned int target;
int target;
if (!cpumask_test_and_clear_cpu(cpu, &cci_pmu->cpus))
if (!g_cci_pmu || cpu != g_cci_pmu->cpu)
return 0;
target = cpumask_any_but(cpu_online_mask, cpu);
if (target >= nr_cpu_ids)
return 0;
/*
* TODO: migrate context once core races on event->ctx have
* been fixed.
*/
cpumask_set_cpu(target, &cci_pmu->cpus);
perf_pmu_migrate_context(&g_cci_pmu->pmu, cpu, target);
g_cci_pmu->cpu = target;
return 0;
}
@ -1706,7 +1699,7 @@ static int cci_pmu_probe(struct platform_device *pdev)
raw_spin_lock_init(&cci_pmu->hw_events.pmu_lock);
mutex_init(&cci_pmu->reserve_mutex);
atomic_set(&cci_pmu->active_events, 0);
cpumask_set_cpu(get_cpu(), &cci_pmu->cpus);
cci_pmu->cpu = get_cpu();
ret = cci_pmu_init(cci_pmu, pdev);
if (ret) {
@ -1714,9 +1707,11 @@ static int cci_pmu_probe(struct platform_device *pdev)
return ret;
}
cpuhp_state_add_instance_nocalls(CPUHP_AP_PERF_ARM_CCI_ONLINE,
&cci_pmu->node);
cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ARM_CCI_ONLINE,
"perf/arm/cci:online", NULL,
cci_pmu_offline_cpu);
put_cpu();
g_cci_pmu = cci_pmu;
pr_info("ARM %s PMU driver probed", cci_pmu->model->name);
return 0;
}
@ -1729,19 +1724,6 @@ static struct platform_driver cci_pmu_driver = {
.probe = cci_pmu_probe,
};
static int __init cci_platform_init(void)
{
int ret;
ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_CCI_ONLINE,
"perf/arm/cci:online", NULL,
cci_pmu_offline_cpu);
if (ret)
return ret;
return platform_driver_register(&cci_pmu_driver);
}
device_initcall(cci_platform_init);
builtin_platform_driver(cci_pmu_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ARM CCI PMU support");