Merge "Perf: arm64: stop counters when going into hotplug" (dc82df31) · Commits · e / devices / android_kernel_sony_msm8994

arch/arm64/kernel/perf_debug.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -36,6 +36,7 @@ static char *descriptions =
		"11 Perf: arm64: Refine disable/enable in tracecounters\n"
		"12 Perf: arm64: fix disable of pmu irq during hotplug\n"
		"13 Perf: arm64: restore registers after reset\n"
		"14 Perf: arm64: stop counters when going into hotplug\n"
		;

		static ssize_t desc_read(struct file fp, char __user buf,

arch/arm64/kernel/perf_event.c

+51 −2

Original line number	Diff line number	Diff line
		@@ -52,6 +52,7 @@ static DEFINE_PER_CPU(unsigned long [BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)], used_m
		static DEFINE_PER_CPU(struct pmu_hw_events, cpu_hw_events);
		static DEFINE_PER_CPU(u32, from_idle);
		static DEFINE_PER_CPU(u32, armv8_pm_pmuserenr);
		static DEFINE_PER_CPU(u32, hotplug_down);

		#define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu))
		static struct pmu_hw_events *armpmu_get_cpu_events(void);
		@@ -1462,6 +1463,48 @@ static void armpmu_update_counters(void *x)
		}
		}

		static void armpmu_hotplug_enable(void *parm_pmu)
		{
		struct arm_pmu *armpmu = parm_pmu;
		struct pmu *pmu = &(armpmu->pmu);
		struct pmu_hw_events *hw_events = armpmu->get_hw_events();
		int idx;

		for (idx = 0; idx <= armpmu->num_events; ++idx) {
		struct perf_event *event = hw_events->events[idx];
		if (!event)
		continue;

		event->state = event->hotplug_save_state;
		pmu->start(event, 0);
		}
		per_cpu(hotplug_down, smp_processor_id()) = 0;
		}

		static void armpmu_hotplug_disable(void *parm_pmu)
		{
		struct arm_pmu *armpmu = parm_pmu;
		struct pmu *pmu = &(armpmu->pmu);
		struct pmu_hw_events *hw_events = armpmu->get_hw_events();
		int idx;

		for (idx = 0; idx <= armpmu->num_events; ++idx) {
		struct perf_event *event = hw_events->events[idx];
		if (!event)
		continue;

		event->hotplug_save_state = event->state;
		/*
		* Prevent timer tick handler perf callback from enabling
		* this event and potentially generating an interrupt
		* before the CPU goes down.
		*/
		event->state = PERF_EVENT_STATE_OFF;
		pmu->stop(event, 0);
		}
		per_cpu(hotplug_down, smp_processor_id()) = 1;
		}

		/*
		* PMU hardware loses all context when a CPU goes offline.
		* When a CPU is hotplugged back in, since some hardware registers are
		@@ -1479,6 +1522,7 @@ static int __cpuinit cpu_pmu_notify(struct notifier_block *b,
		int ret = NOTIFY_DONE;

		if ((masked_action != CPU_DOWN_PREPARE) &&
		(masked_action != CPU_DOWN_FAILED) &&
		(masked_action != CPU_STARTING))
		return NOTIFY_DONE;

		@@ -1496,7 +1540,7 @@ static int __cpuinit cpu_pmu_notify(struct notifier_block *b,
		if (cpu_pmu->pmu_state != ARM_PMU_STATE_OFF) {
		if (cpu_has_active_perf(cpu))
		smp_call_function_single(cpu,
		armpmu_update_counters, NULL, 1);
		armpmu_hotplug_disable, cpu_pmu, 1);
		/* Disarm the PMU IRQ before disappearing. */
		if (msm_pmu_use_irq && cpu_pmu->plat_device) {
		irq = platform_get_irq(cpu_pmu->plat_device, 0);
		@@ -1507,6 +1551,7 @@ static int __cpuinit cpu_pmu_notify(struct notifier_block *b,
		break;

		case CPU_STARTING:
		case CPU_DOWN_FAILED:
		/* Reset PMU to clear counters for ftrace buffer */
		if (cpu_pmu->reset)
		cpu_pmu->reset(NULL);
		@@ -1519,7 +1564,7 @@ static int __cpuinit cpu_pmu_notify(struct notifier_block *b,
		armpmu_enable_percpu_irq(&irq);
		}
		if (cpu_has_active_perf(cpu)) {
		__get_cpu_var(from_idle) = 1;
		armpmu_hotplug_enable(cpu_pmu);
		pmu = &cpu_pmu->pmu;
		pmu->pmu_enable(pmu);
		}
		@@ -1543,6 +1588,10 @@ static int perf_cpu_pm_notifier(struct notifier_block *self, unsigned long cmd,
		if (!cpu_pmu)
		return NOTIFY_OK;

		/* If the cpu is going down, don't do anything here */
		if (per_cpu(hotplug_down, cpu))
		return NOTIFY_OK;

		switch (cmd) {
		case CPU_PM_ENTER:
		if (cpu_pmu->save_pm_registers)