[PATCH V4 2/2] arm64: perf: add support for percpu pmu interrupt

From: Vinayak Kale
Date: Wed Nov 20 2013 - 06:14:19 EST


Add support for irq registration when pmu interrupt is percpu.

Signed-off-by: Vinayak Kale <vkale@xxxxxxx>
Signed-off-by: Tuan Phan <tphan@xxxxxxx>
---
arch/arm64/kernel/perf_event.c | 108 ++++++++++++++++++++++++++++++----------
1 file changed, 81 insertions(+), 27 deletions(-)

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index cea1594..de12ba8 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -22,6 +22,7 @@

#include <linux/bitmap.h>
#include <linux/interrupt.h>
+#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/perf_event.h>
@@ -363,22 +364,55 @@ validate_group(struct perf_event *event)
}

static void
+armpmu_disable_percpu_irq(void *data)
+{
+ struct arm_pmu *armpmu = data;
+ struct platform_device *pmu_device = armpmu->plat_device;
+ int irq = platform_get_irq(pmu_device, 0);
+
+ cpumask_test_and_clear_cpu(smp_processor_id(), &armpmu->active_irqs);
+ disable_percpu_irq(irq);
+}
+
+static void
armpmu_release_hardware(struct arm_pmu *armpmu)
{
int i, irq, irqs;
struct platform_device *pmu_device = armpmu->plat_device;

irqs = min(pmu_device->num_resources, num_possible_cpus());
+ if (irqs < 1)
+ return;

- for (i = 0; i < irqs; ++i) {
- if (!cpumask_test_and_clear_cpu(i, &armpmu->active_irqs))
- continue;
- irq = platform_get_irq(pmu_device, i);
- if (irq >= 0)
- free_irq(irq, armpmu);
+ irq = platform_get_irq(pmu_device, 0);
+ if (irq < 0)
+ return;
+
+ if (irq_is_percpu(irq)) {
+ on_each_cpu(armpmu_disable_percpu_irq, armpmu, 1);
+ free_percpu_irq(irq, &cpu_hw_events);
+ } else {
+ for (i = 0; i < irqs; ++i) {
+ if (!cpumask_test_and_clear_cpu(i, &armpmu->active_irqs))
+ continue;
+ irq = platform_get_irq(pmu_device, i);
+ if (irq >= 0)
+ free_irq(irq, armpmu);
+ }
}
}

+static void
+armpmu_enable_percpu_irq(void *data)
+{
+ struct arm_pmu *armpmu = data;
+ struct platform_device *pmu_device = armpmu->plat_device;
+ int irq = platform_get_irq(pmu_device, 0);
+
+ enable_percpu_irq(irq, 0);
+ cpumask_set_cpu(smp_processor_id(), &armpmu->active_irqs);
+}
+
static int
armpmu_reserve_hardware(struct arm_pmu *armpmu)
{
@@ -396,34 +430,54 @@ armpmu_reserve_hardware(struct arm_pmu *armpmu)
return -ENODEV;
}

- for (i = 0; i < irqs; ++i) {
- err = 0;
- irq = platform_get_irq(pmu_device, i);
- if (irq < 0)
- continue;
+ irq = platform_get_irq(pmu_device, 0);
+ if (irq < 0) {
+ pr_err("failed to get an irq for PMU device\n");
+ return -ENODEV;
+ }

- /*
- * If we have a single PMU interrupt that we can't shift,
- * assume that we're running on a uniprocessor machine and
- * continue. Otherwise, continue without this interrupt.
- */
- if (irq_set_affinity(irq, cpumask_of(i)) && irqs > 1) {
- pr_warning("unable to set irq affinity (irq=%d, cpu=%u)\n",
- irq, i);
- continue;
- }
+ if (irq_is_percpu(irq)) {
+ err = request_percpu_irq(irq, armpmu->handle_irq,
+ "arm-pmu", &cpu_hw_events);

- err = request_irq(irq, armpmu->handle_irq,
- IRQF_NOBALANCING,
- "arm-pmu", armpmu);
if (err) {
- pr_err("unable to request IRQ%d for ARM PMU counters\n",
- irq);
+ pr_err("unable to request percpu IRQ%d for ARM PMU counters\n",
+ irq);
armpmu_release_hardware(armpmu);
return err;
}

- cpumask_set_cpu(i, &armpmu->active_irqs);
+ on_each_cpu(armpmu_enable_percpu_irq, armpmu, 1);
+ } else {
+ for (i = 0; i < irqs; ++i) {
+ err = 0;
+ irq = platform_get_irq(pmu_device, i);
+ if (irq < 0)
+ continue;
+
+ /*
+ * If we have a single PMU interrupt that we can't shift,
+ * assume that we're running on a uniprocessor machine and
+ * continue. Otherwise, continue without this interrupt.
+ */
+ if (irq_set_affinity(irq, cpumask_of(i)) && irqs > 1) {
+ pr_warning("unable to set irq affinity (irq=%d, cpu=%u)\n",
+ irq, i);
+ continue;
+ }
+
+ err = request_irq(irq, armpmu->handle_irq,
+ IRQF_NOBALANCING,
+ "arm-pmu", armpmu);
+ if (err) {
+ pr_err("unable to request IRQ%d for ARM PMU counters\n",
+ irq);
+ armpmu_release_hardware(armpmu);
+ return err;
+ }
+
+ cpumask_set_cpu(i, &armpmu->active_irqs);
+ }
}

return 0;
--
1.7.9.5

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