[PATCH 2/2] arm: pmu: add support for per-cpu PMU interrupts.

From: y
Date: Mon Jul 30 2012 - 10:12:53 EST


From: Chris Smith <chris.smith@xxxxxx>

We have systems where the PMU interrupts are PPIs, and so per-cpu. This
patch adds support for per-cpu PMU interrupts to the perf event code.

Note that because the dev_id passed to request_percpu_irq has to be
percpu data, we now pass cpu_hw_events as the dev_id rather than armpmu.
This only place the dev_id was used was in armpmu_platform_irq, which is
fixed up accordingly.

Signed-off-by: Chris Smith <chris.smith@xxxxxx>
---
arch/arm/kernel/perf_event.c | 91 +++++++++++++++++++++++++++++---------
arch/arm/kernel/perf_event_v6.c | 3 +-
arch/arm/kernel/perf_event_v7.c | 3 +-
3 files changed, 71 insertions(+), 26 deletions(-)

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index b2abfa1..add9064 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -14,6 +14,7 @@

#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>
@@ -355,13 +356,27 @@ validate_group(struct perf_event *event)

static irqreturn_t armpmu_platform_irq(int irq, void *dev)
{
- struct arm_pmu *armpmu = (struct arm_pmu *) dev;
+ struct pmu_hw_events *cpuc = (struct pmu_hw_events *)dev;
+ struct arm_pmu *armpmu = to_arm_pmu((*(cpuc->events))->pmu);
+
struct platform_device *plat_device = armpmu->plat_device;
struct arm_pmu_platdata *plat = dev_get_platdata(&plat_device->dev);

return plat->handle_irq(irq, dev, armpmu->handle_irq);
}

+/* Wrap enable_percpu_irq up as a smp_call_func_t */
+static void armpmu_enable_percpu_irq(void *irq)
+{
+ enable_percpu_irq((int)irq, IRQ_TYPE_NONE);
+}
+
+/* Wrap disable_percpu_irq up as a smp_call_func_t */
+static void armpmu_disable_percpu_irq(void *irq)
+{
+ disable_percpu_irq((int)irq);
+}
+
static void
armpmu_release_hardware(struct arm_pmu *armpmu)
{
@@ -379,7 +394,14 @@ armpmu_release_hardware(struct arm_pmu *armpmu)
if (irq >= 0) {
if (plat && plat->disable_irq)
plat->disable_irq(irq);
- free_irq(irq, armpmu);
+ else if (irq_is_per_cpu(irq))
+ on_each_cpu(armpmu_disable_percpu_irq,
+ (void *)irq, 1);
+
+ if (irq_is_per_cpu(irq))
+ free_percpu_irq(irq, &cpu_hw_events);
+ else
+ free_irq(irq, &per_cpu(cpu_hw_events, i));
}
}

@@ -421,28 +443,53 @@ armpmu_reserve_hardware(struct arm_pmu *armpmu)
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;
+ if (irq_is_per_cpu(irq)) {
+ /*
+ * We assume that if the PMU IRQ is per-cpu, then
+ * there is only one.
+ */
+ WARN_ON(irqs > 1);
+
+ err = request_percpu_irq(irq, handle_irq,
+ "arm-pmu", &cpu_hw_events);
+ if (err) {
+ pr_err("unable to request IRQ%d for ARM PMU counters\n",
+ irq);
+ armpmu_release_hardware(armpmu);
+ return err;
+ } else if (plat && plat->enable_irq) {
+ plat->enable_irq(irq);
+ } else {
+ on_each_cpu(armpmu_enable_percpu_irq,
+ (void *)irq, 1);
+ }
+
+ } else {
+ /*
+ * 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, handle_irq,
+ IRQF_DISABLED | IRQF_NOBALANCING,
+ "arm-pmu", &per_cpu(cpu_hw_events, i));
+
+ if (err) {
+ pr_err("unable to request IRQ%d for ARM PMU counters\n",
+ irq);
+ armpmu_release_hardware(armpmu);
+ return err;
+ } else if (plat && plat->enable_irq)
+ plat->enable_irq(irq);
}

- err = request_irq(irq, handle_irq,
- IRQF_DISABLED | 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;
- } else if (plat && plat->enable_irq)
- plat->enable_irq(irq);
-
cpumask_set_cpu(i, &armpmu->active_irqs);
}

diff --git a/arch/arm/kernel/perf_event_v6.c b/arch/arm/kernel/perf_event_v6.c
index b78af0c..6b348f5 100644
--- a/arch/arm/kernel/perf_event_v6.c
+++ b/arch/arm/kernel/perf_event_v6.c
@@ -473,7 +473,7 @@ armv6pmu_handle_irq(int irq_num,
{
unsigned long pmcr = armv6_pmcr_read();
struct perf_sample_data data;
- struct pmu_hw_events *cpuc;
+ struct pmu_hw_events *cpuc = (struct pmu_hw_events *)dev;
struct pt_regs *regs;
int idx;

@@ -491,7 +491,6 @@ armv6pmu_handle_irq(int irq_num,

perf_sample_data_init(&data, 0);

- cpuc = &__get_cpu_var(cpu_hw_events);
for (idx = 0; idx < cpu_pmu->num_events; ++idx) {
struct perf_event *event = cpuc->events[idx];
struct hw_perf_event *hwc;
diff --git a/arch/arm/kernel/perf_event_v7.c b/arch/arm/kernel/perf_event_v7.c
index 4d7095a..56ddad7 100644
--- a/arch/arm/kernel/perf_event_v7.c
+++ b/arch/arm/kernel/perf_event_v7.c
@@ -933,7 +933,7 @@ static irqreturn_t armv7pmu_handle_irq(int irq_num, void *dev)
{
u32 pmnc;
struct perf_sample_data data;
- struct pmu_hw_events *cpuc;
+ struct pmu_hw_events *cpuc = (struct pmu_hw_events *)dev;
struct pt_regs *regs;
int idx;

@@ -955,7 +955,6 @@ static irqreturn_t armv7pmu_handle_irq(int irq_num, void *dev)

perf_sample_data_init(&data, 0);

- cpuc = &__get_cpu_var(cpu_hw_events);
for (idx = 0; idx < cpu_pmu->num_events; ++idx) {
struct perf_event *event = cpuc->events[idx];
struct hw_perf_event *hwc;
--
1.7.6.5

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