Merge "Perf: arm: disable perf_event_read during hotplug" (191ff2f4) · Commits · e / devices / android_kernel_fairphone_FP3

arch/arm64/kernel/perf_event.c

+48 −3

Original line number	Diff line number	Diff line
		@@ -29,6 +29,8 @@
		#include <linux/perf/arm_pmu.h>
		#include <linux/platform_device.h>

		static DEFINE_PER_CPU(bool, is_hotplugging);

		/*
		* ARMv8 PMUv3 Performance Events handling code.
		* Common event types (some are defined in asm/perf_event.h).
		@@ -982,6 +984,9 @@ static void armv8pmu_idle_update(struct arm_pmu *cpu_pmu)
		if (!cpu_pmu)
		return;

		if (__this_cpu_read(is_hotplugging))
		return;

		hw_events = this_cpu_ptr(cpu_pmu->hw_events);

		if (!hw_events)
		@@ -1031,14 +1036,13 @@ static int armv8pmu_probe_pmu(struct arm_pmu *cpu_pmu)

		pmu_idle_nb->cpu_pmu = cpu_pmu;
		pmu_idle_nb->perf_cpu_idle_nb.notifier_call = perf_cpu_idle_notifier;
		idle_notifier_register(&pmu_idle_nb->perf_cpu_idle_nb);

		ret = smp_call_function_any(&cpu_pmu->supported_cpus,
		__armv8pmu_probe_pmu,
		cpu_pmu, 1);

		if (ret)
		idle_notifier_unregister(&pmu_idle_nb->perf_cpu_idle_nb);
		if (!ret)
		idle_notifier_register(&pmu_idle_nb->perf_cpu_idle_nb);

		return ret;
		}
		@@ -1140,6 +1144,37 @@ static const struct of_device_id armv8_pmu_of_device_ids[] = {
		{},
		};

		#ifdef CONFIG_HOTPLUG_CPU
		static int perf_event_hotplug_coming_up(unsigned int cpu)
		{
		per_cpu(is_hotplugging, cpu) = false;
		return 0;
		}

		static int perf_event_hotplug_going_down(unsigned int cpu)
		{
		per_cpu(is_hotplugging, cpu) = true;
		return 0;
		}

		static int perf_event_cpu_hp_init(void)
		{
		int ret;

		ret = cpuhp_setup_state_nocalls(CPUHP_AP_NOTIFY_ONLINE,
		"PERF_EVENT/CPUHP_AP_NOTIFY_ONLINE",
		perf_event_hotplug_coming_up,
		perf_event_hotplug_going_down);
		if (ret)
		pr_err("CPU hotplug notifier for perf_event.c could not be registered: %d\n",
		ret);

		return ret;
		}
		#else
		static int perf_event_cpu_hp_init(void) { return 0; }
		#endif

		/*
		* Non DT systems have their micro/arch events probed at run-time.
		* A fairly complete list of generic events are provided and ones that
		@@ -1152,6 +1187,16 @@ static const struct pmu_probe_info armv8_pmu_probe_table[] = {

		static int armv8_pmu_device_probe(struct platform_device *pdev)
		{
		int ret, cpu;

		for_each_possible_cpu(cpu)
		per_cpu(is_hotplugging, cpu) = false;

		ret = perf_event_cpu_hp_init();

		if (ret)
		return ret;

		if (acpi_disabled)
		return arm_pmu_device_probe(pdev, armv8_pmu_of_device_ids,
		NULL);

kernel/events/core.c

+41 −45

Original line number	Diff line number	Diff line
		@@ -373,6 +373,7 @@ static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
		static DEFINE_PER_CPU(int, perf_sched_cb_usages);
		static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
		static DEFINE_PER_CPU(bool, is_idle);
		static DEFINE_PER_CPU(bool, is_hotplugging);

		static atomic_t nr_mmap_events __read_mostly;
		static atomic_t nr_comm_events __read_mostly;
		@@ -3495,6 +3496,9 @@ static void __perf_event_read(void *info)
		struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
		struct pmu *pmu = event->pmu;

		if (__this_cpu_read(is_hotplugging))
		return;

		/*
		* If this is a task context, we need to check whether it is
		* the current task context of this cpu. If not it has been
		@@ -3619,7 +3623,8 @@ static int perf_event_read(struct perf_event *event, bool group)
		return 0;
		if (cpu_isolated(event_cpu) \|\|
		(event->attr.exclude_idle &&
		per_cpu(is_idle, event_cpu)))
		per_cpu(is_idle, event_cpu)) \|\|
		per_cpu(is_hotplugging, event_cpu))
		active_event_skip_read = true;
		}

		@@ -3649,7 +3654,8 @@ static int perf_event_read(struct perf_event *event, bool group)
		preempt_enable();
		ret = data.ret;
		} else if (event->state == PERF_EVENT_STATE_INACTIVE \|\|
		active_event_skip_read) {
		(active_event_skip_read &&
		!per_cpu(is_hotplugging, event_cpu))) {
		struct perf_event_context *ctx = event->ctx;
		unsigned long flags;

		@@ -10711,6 +10717,8 @@ static void __init perf_event_init_all_cpus(void)
		raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));

		INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
		per_cpu(is_hotplugging, cpu) = false;
		per_cpu(is_idle, cpu) = false;
		}
		}

		@@ -10734,19 +10742,10 @@ int perf_event_init_cpu(unsigned int cpu)
		static void
		check_hotplug_start_event(struct perf_event *event)
		{
		if (event->attr.type == PERF_TYPE_SOFTWARE) {
		switch (event->attr.config) {
		case PERF_COUNT_SW_CPU_CLOCK:
		cpu_clock_event_start(event, 0);
		break;
		case PERF_COUNT_SW_TASK_CLOCK:
		break;
		default:
		if (event->pmu->start)
		if (event->pmu->events_across_hotplug &&
		event->attr.type == PERF_TYPE_SOFTWARE &&
		event->pmu->start)
		event->pmu->start(event, 0);
		break;
		}
		}
		}

		static int perf_event_start_swevents(unsigned int cpu)
		@@ -10767,6 +10766,7 @@ static int perf_event_start_swevents(unsigned int cpu)
		mutex_unlock(&ctx->mutex);
		}
		srcu_read_unlock(&pmus_srcu, idx);
		per_cpu(is_hotplugging, cpu) = false;
		return 0;
		}

		@@ -10783,22 +10783,13 @@ check_hotplug_remove_from_context(struct perf_event *event,
		struct perf_cpu_context *cpuctx,
		struct perf_event_context *ctx)
		{
		if (!event->pmu->events_across_hotplug) {
		if (event->pmu->events_across_hotplug &&
		event->attr.type == PERF_TYPE_SOFTWARE &&
		event->pmu->stop)
		event->pmu->stop(event, PERF_EF_UPDATE);
		else if (!event->pmu->events_across_hotplug)
		__perf_remove_from_context(event, cpuctx,
		ctx, (void *)DETACH_GROUP);
		} else if (event->attr.type == PERF_TYPE_SOFTWARE) {
		switch (event->attr.config) {
		case PERF_COUNT_SW_CPU_CLOCK:
		cpu_clock_event_stop(event, 0);
		break;
		case PERF_COUNT_SW_TASK_CLOCK:
		break;
		default:
		if (event->pmu->stop)
		event->pmu->stop(event, 0);
		break;
		}
		}
		}

		static void __perf_event_exit_context(void *__info)
		@@ -10837,6 +10828,7 @@ static void perf_event_exit_cpu_context(int cpu) { }

		int perf_event_exit_cpu(unsigned int cpu)
		{
		per_cpu(is_hotplugging, cpu) = true;
		perf_event_exit_cpu_context(cpu);
		return 0;
		}
		@@ -10880,6 +10872,24 @@ static struct notifier_block perf_event_idle_nb = {
		.notifier_call = event_idle_notif,
		};

		#ifdef CONFIG_HOTPLUG_CPU
		static int perf_cpu_hp_init(void)
		{
		int ret;

		ret = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ONLINE,
		"PERF/CORE/CPUHP_AP_PERF_ONLINE",
		perf_event_start_swevents,
		perf_event_exit_cpu);
		if (ret)
		pr_err("CPU hotplug notifier for perf core could not be registered: %d\n",
		ret);

		return ret;
		}
		#else
		static int perf_cpu_hp_init(void) { return 0; }
		#endif

		void __init perf_event_init(void)
		{
		@@ -10896,6 +10906,8 @@ void __init perf_event_init(void)
		perf_event_init_cpu(smp_processor_id());
		idle_notifier_register(&perf_event_idle_nb);
		register_reboot_notifier(&perf_reboot_notifier);
		ret = perf_cpu_hp_init();
		WARN(ret, "core perf_cpu_hp_init() failed with: %d", ret);

		ret = init_hw_breakpoint();
		WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
		@@ -10949,22 +10961,6 @@ static int __init perf_event_sysfs_init(void)
		}
		device_initcall(perf_event_sysfs_init);

		#ifdef CONFIG_HOTPLUG_CPU
		static int perf_cpu_hp_init(void)
		{
		int ret;

		ret = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ONLINE,
		"PERF/CORE/AP_PERF_ONLINE",
		perf_event_start_swevents,
		perf_event_exit_cpu);
		if (ret)
		pr_err("CPU hotplug notifier for perf core could not be registered: %d\n",
		ret);
		return ret;
		}
		subsys_initcall(perf_cpu_hp_init);
		#endif

		#ifdef CONFIG_CGROUP_PERF
		static struct cgroup_subsys_state *