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Subject[PATCH 2/2] arm64: perf: add support for percpu pmu interrupt
Date
Add support for irq registration when pmu interrupt is percpu.

Signed-off-by: Vinayak Kale <vkale@apm.com>
Signed-off-by: Tuan Phan <tphan@apm.com>
---
arch/arm64/kernel/perf_event.c | 109 +++++++++++++++++++++++++++++-----------
1 file changed, 81 insertions(+), 28 deletions(-)

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index cea1594..e60dae3 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -44,6 +44,7 @@
static DEFINE_PER_CPU(struct perf_event * [ARMPMU_MAX_HWEVENTS], hw_events);
static DEFINE_PER_CPU(unsigned long [BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)], used_mask);
static DEFINE_PER_CPU(struct pmu_hw_events, cpu_hw_events);
+static bool is_percpuirq;

#define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu))

@@ -363,22 +364,51 @@ validate_group(struct perf_event *event)
}

static void
+armpmu_disable_percpu_irq(void *data)
+{
+ struct arm_pmu *armpmu = (struct arm_pmu *)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());
+ irq = platform_get_irq(pmu_device, 0);

- 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);
+ if (is_percpuirq) {
+ on_each_cpu(armpmu_disable_percpu_irq, (void *)armpmu, 1);
+ free_percpu_irq(irq, &cpu_hw_events);
+ } else {
+ irqs = min(pmu_device->num_resources, num_possible_cpus());
+
+ 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 = (struct arm_pmu *)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 +426,57 @@ 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 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;
- }
+ /*
+ * Try 'request_percpu_irq' first. If it's return value indicates
+ * that irq is not percpu then try 'request_irq'
+ */
+ err = request_percpu_irq(irq, armpmu->handle_irq,
+ "arm-pmu", &cpu_hw_events);
+ if (err != -EPERM) {
+ is_percpuirq = true;

- 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, (void *)armpmu, 1);
+ } else {
+ is_percpuirq = false;
+
+ 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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