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Commit 5ebd9200 authored by Mark Rutland's avatar Mark Rutland Committed by Will Deacon
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arm: perf: fold percpu_pmu into pmu_hw_events 



Currently the percpu_pmu pointers used as percpu_irq dev_id values are
defined separately from the other per-cpu accounting data, which make
dynamically allocating the data (as will be required for systems with
heterogeneous CPUs) difficult.

This patch moves the percpu_pmu pointers into pmu_hw_events (which is
itself allocated per cpu), which will allow for easier dynamic
allocation. Both percpu and regular irqs are requested using percpu_pmu
pointers as tokens, freeing us from having to know whether an irq is
percpu within the handler, and thus avoiding a radix tree lookup on the
handler path.

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Reviewed-by: default avatarWill Deacon <will.deacon@arm.com>
Reviewed-by: default avatarStephen Boyd <sboyd@codeaurora.org>
Tested-by: default avatarStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 11679250

arch/arm/include/asm/pmu.h

+6 −0
Original line number Diff line number Diff line
@@ -81,6 +81,12 @@ struct pmu_hw_events { 
	 * read/modify/write sequences.

	 */

	raw_spinlock_t		pmu_lock;



	/*

	 * When using percpu IRQs, we need a percpu dev_id. Place it here as we

	 * already have to allocate this struct per cpu.

	 */

	struct arm_pmu		*percpu_pmu;

};



struct arm_pmu {

arch/arm/kernel/perf_event.c

+9 −5
Original line number Diff line number Diff line
@@ -304,17 +304,21 @@ static irqreturn_t armpmu_dispatch_irq(int irq, void *dev) 
	int ret;

	u64 start_clock, finish_clock;



	if (irq_is_percpu(irq))

		dev = *(void **)dev;

	armpmu = dev;

	/*

	 * we request the IRQ with a (possibly percpu) struct arm_pmu**, but

	 * the handlers expect a struct arm_pmu*. The percpu_irq framework will

	 * do any necessary shifting, we just need to perform the first

	 * dereference.

	 */

	armpmu = *(void **)dev;

	plat_device = armpmu->plat_device;

	plat = dev_get_platdata(&plat_device->dev);



	start_clock = sched_clock();

	if (plat && plat->handle_irq)

		ret = plat->handle_irq(irq, dev, armpmu->handle_irq);

		ret = plat->handle_irq(irq, armpmu, armpmu->handle_irq);

	else

		ret = armpmu->handle_irq(irq, dev);

		ret = armpmu->handle_irq(irq, armpmu);

	finish_clock = sched_clock();



	perf_sample_event_took(finish_clock - start_clock);

arch/arm/kernel/perf_event_cpu.c

+8 −6
Original line number Diff line number Diff line
@@ -35,7 +35,6 @@ 
/* Set at runtime when we know what CPU type we are. */

static struct arm_pmu *cpu_pmu;



static DEFINE_PER_CPU(struct arm_pmu *, percpu_pmu);

static DEFINE_PER_CPU(struct pmu_hw_events, cpu_hw_events);



/*
@@ -85,20 +84,21 @@ static void cpu_pmu_free_irq(struct arm_pmu *cpu_pmu) 
{

	int i, irq, irqs;

	struct platform_device *pmu_device = cpu_pmu->plat_device;

	struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;



	irqs = min(pmu_device->num_resources, num_possible_cpus());



	irq = platform_get_irq(pmu_device, 0);

	if (irq >= 0 && irq_is_percpu(irq)) {

		on_each_cpu(cpu_pmu_disable_percpu_irq, &irq, 1);

		free_percpu_irq(irq, &percpu_pmu);

		free_percpu_irq(irq, &hw_events->percpu_pmu);

	} else {

		for (i = 0; i < irqs; ++i) {

			if (!cpumask_test_and_clear_cpu(i, &cpu_pmu->active_irqs))

				continue;

			irq = platform_get_irq(pmu_device, i);

			if (irq >= 0)

				free_irq(irq, cpu_pmu);

				free_irq(irq, per_cpu_ptr(&hw_events->percpu_pmu, i));

		}

	}

}
@@ -107,6 +107,7 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler) 
{

	int i, err, irq, irqs;

	struct platform_device *pmu_device = cpu_pmu->plat_device;

	struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;



	if (!pmu_device)

		return -ENODEV;
@@ -119,7 +120,8 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler) 


	irq = platform_get_irq(pmu_device, 0);

	if (irq >= 0 && irq_is_percpu(irq)) {

		err = request_percpu_irq(irq, handler, "arm-pmu", &percpu_pmu);

		err = request_percpu_irq(irq, handler, "arm-pmu",

					 &hw_events->percpu_pmu);

		if (err) {

			pr_err("unable to request IRQ%d for ARM PMU counters\n",

				irq);
@@ -146,7 +148,7 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler) 


			err = request_irq(irq, handler,

					  IRQF_NOBALANCING | IRQF_NO_THREAD, "arm-pmu",

					  cpu_pmu);

					  per_cpu_ptr(&hw_events->percpu_pmu, i));

			if (err) {

				pr_err("unable to request IRQ%d for ARM PMU counters\n",

					irq);
@@ -166,7 +168,7 @@ static void cpu_pmu_init(struct arm_pmu *cpu_pmu) 
	for_each_possible_cpu(cpu) {

		struct pmu_hw_events *events = &per_cpu(cpu_hw_events, cpu);

		raw_spin_lock_init(&events->pmu_lock);

		per_cpu(percpu_pmu, cpu) = cpu_pmu;

		events->percpu_pmu = cpu_pmu;

	}



	cpu_pmu->hw_events	= &cpu_hw_events;