[PATCH 2/3] drivers/perf: arm_pmu: manage interrupts per-cpu
Mark Rutland
mark.rutland at arm.com
Mon Jan 30 07:31:18 PST 2017
When requesting or freeing interrupts, we use platform_get_irq() to find
relevant irqs, backing this up with additional information in an
optional irq_affinity table.
This means that our irq request and free paths are tied to a
platform_device, and our request path must jump through a number of
hoops in order to determine the required affinity of each interrupt.
Given that the affinity must be static, we can compute the affinity once
up-front at probe time, simplifying the irq request and free paths. By
recording interrupts in a per-cpu data structure, we simplify a few
paths, and permit a subsequent rework of the request and free paths.
Signed-off-by: Mark Rutland <mark.rutland at arm.com>
Cc: Will Deacon <will.deacon at arm.com>
---
drivers/perf/arm_pmu.c | 281 +++++++++++++++++++++----------------------
include/linux/perf/arm_pmu.h | 2 +
2 files changed, 141 insertions(+), 142 deletions(-)
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index dc4c8aa..23976f7 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -616,94 +616,76 @@ static void cpu_pmu_disable_percpu_irq(void *data)
static void cpu_pmu_free_irq(struct arm_pmu *cpu_pmu)
{
- int i, irq, irqs;
- struct platform_device *pmu_device = cpu_pmu->plat_device;
+ int cpu;
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_mask(&cpu_pmu->supported_cpus,
- cpu_pmu_disable_percpu_irq, &irq, 1);
- free_percpu_irq(irq, &hw_events->percpu_pmu);
- } else {
- for (i = 0; i < irqs; ++i) {
- int cpu = i;
-
- if (cpu_pmu->irq_affinity)
- cpu = cpu_pmu->irq_affinity[i];
-
- if (!cpumask_test_and_clear_cpu(cpu, &cpu_pmu->active_irqs))
- continue;
- irq = platform_get_irq(pmu_device, i);
- if (irq > 0)
- free_irq(irq, per_cpu_ptr(&hw_events->percpu_pmu, cpu));
+ for_each_cpu(cpu, &cpu_pmu->supported_cpus) {
+ int irq = per_cpu(hw_events->irq, cpu);
+ if (!irq)
+ continue;
+
+ if (irq_is_percpu(irq)) {
+ on_each_cpu_mask(&cpu_pmu->supported_cpus,
+ cpu_pmu_disable_percpu_irq, &irq, 1);
+ free_percpu_irq(irq, &hw_events->percpu_pmu);
+
+ break;
}
+
+ if (!cpumask_test_and_clear_cpu(cpu, &cpu_pmu->active_irqs))
+ continue;
+
+ free_irq(irq, per_cpu_ptr(&hw_events->percpu_pmu, cpu));
}
}
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;
+ int cpu, err;
struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;
- if (!pmu_device)
- return -ENODEV;
-
- irqs = min(pmu_device->num_resources, num_possible_cpus());
- if (irqs < 1) {
- pr_warn_once("perf/ARM: No irqs for PMU defined, sampling events not supported\n");
- return 0;
- }
-
- irq = platform_get_irq(pmu_device, 0);
- if (irq > 0 && irq_is_percpu(irq)) {
- 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);
- return err;
- }
-
- on_each_cpu_mask(&cpu_pmu->supported_cpus,
- cpu_pmu_enable_percpu_irq, &irq, 1);
- } else {
- for (i = 0; i < irqs; ++i) {
- int cpu = i;
-
- err = 0;
- irq = platform_get_irq(pmu_device, i);
- if (irq < 0)
- continue;
-
- if (cpu_pmu->irq_affinity)
- cpu = cpu_pmu->irq_affinity[i];
-
- /*
- * 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(cpu)) && irqs > 1) {
- pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",
- irq, cpu);
- continue;
- }
+ for_each_cpu(cpu, &cpu_pmu->supported_cpus) {
+ int irq = per_cpu(hw_events->irq, cpu);
+ if (!irq)
+ continue;
- err = request_irq(irq, handler,
- IRQF_NOBALANCING | IRQF_NO_THREAD, "arm-pmu",
- per_cpu_ptr(&hw_events->percpu_pmu, cpu));
+ if (irq_is_percpu(irq)) {
+ 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);
return err;
}
- cpumask_set_cpu(cpu, &cpu_pmu->active_irqs);
+ on_each_cpu_mask(&cpu_pmu->supported_cpus,
+ cpu_pmu_enable_percpu_irq, &irq, 1);
+
+ break;
+ }
+
+ /*
+ * 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(cpu)) &&
+ num_possible_cpus() > 1) {
+ pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",
+ irq, cpu);
+ continue;
}
+
+ err = request_irq(irq, handler,
+ IRQF_NOBALANCING | IRQF_NO_THREAD, "arm-pmu",
+ per_cpu_ptr(&hw_events->percpu_pmu, cpu));
+ if (err) {
+ pr_err("unable to request IRQ%d for ARM PMU counters\n",
+ irq);
+ return err;
+ }
+
+ cpumask_set_cpu(cpu, &cpu_pmu->active_irqs);
}
return 0;
@@ -897,98 +879,113 @@ static int probe_current_pmu(struct arm_pmu *pmu,
return ret;
}
-static int of_pmu_irq_cfg(struct arm_pmu *pmu)
+static int of_pmu_irq_cfg_ppi(struct arm_pmu *pmu, int irq)
{
- int *irqs, i = 0;
- bool using_spi = false;
- struct platform_device *pdev = pmu->plat_device;
+ int cpu, ret;
+ struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
- irqs = kcalloc(pdev->num_resources, sizeof(*irqs), GFP_KERNEL);
- if (!irqs)
- return -ENOMEM;
+ ret = irq_get_percpu_devid_partition(irq, &pmu->supported_cpus);
+ if (ret)
+ return ret;
- do {
- struct device_node *dn;
- int cpu, irq;
+ for_each_cpu(cpu, &pmu->supported_cpus)
+ per_cpu(hw_events->irq, cpu) = irq;
- /* See if we have an affinity entry */
- dn = of_parse_phandle(pdev->dev.of_node, "interrupt-affinity", i);
- if (!dn)
- break;
+ return 0;
+}
- /* Check the IRQ type and prohibit a mix of PPIs and SPIs */
- irq = platform_get_irq(pdev, i);
- if (irq > 0) {
- bool spi = !irq_is_percpu(irq);
-
- if (i > 0 && spi != using_spi) {
- pr_err("PPI/SPI IRQ type mismatch for %s!\n",
- dn->name);
- of_node_put(dn);
- kfree(irqs);
- return -EINVAL;
- }
+static int of_pmu_parse_irq_affinity(struct device_node *node, int i)
+{
+ struct device_node *dn;
+ int cpu;
- using_spi = spi;
- }
+ if (!of_find_property(node, "interrupt-affinity", NULL)) {
+ pr_warn("no interrupt-affinity property, guessing IRQ affinity\n");
+ return i;
+ }
- /* Now look up the logical CPU number */
- for_each_possible_cpu(cpu) {
- struct device_node *cpu_dn;
+ dn = of_parse_phandle(node, "interrupt-affinity", i);
+ if (!dn) {
+ pr_warn("failed to parse interrupt-affinity[%d] for %s\n",
+ i, node->name);
+ return -EINVAL;
+ }
- cpu_dn = of_cpu_device_node_get(cpu);
- of_node_put(cpu_dn);
+ /* Now look up the logical CPU number */
+ for_each_possible_cpu(cpu) {
+ struct device_node *cpu_dn;
- if (dn == cpu_dn)
- break;
- }
+ cpu_dn = of_cpu_device_node_get(cpu);
+ of_node_put(cpu_dn);
- if (cpu >= nr_cpu_ids) {
- pr_warn("Failed to find logical CPU for %s\n",
- dn->name);
- of_node_put(dn);
- cpumask_setall(&pmu->supported_cpus);
+ if (dn == cpu_dn)
break;
- }
- of_node_put(dn);
+ }
- /* For SPIs, we need to track the affinity per IRQ */
- if (using_spi) {
- if (i >= pdev->num_resources)
- break;
+ if (cpu >= nr_cpu_ids) {
+ pr_warn("failed to find logical CPU for %s\n", dn->name);
+ }
- irqs[i] = cpu;
- }
+ of_node_put(dn);
- /* Keep track of the CPUs containing this PMU type */
- cpumask_set_cpu(cpu, &pmu->supported_cpus);
- i++;
- } while (1);
+ return cpu;
+}
- /* If we didn't manage to parse anything, try the interrupt affinity */
- if (cpumask_weight(&pmu->supported_cpus) == 0) {
- int irq = platform_get_irq(pdev, 0);
+static int of_pmu_irq_cfg(struct arm_pmu *pmu)
+{
+ int i = 0, nr_irqs;
+ struct platform_device *pdev = pmu->plat_device;
+ struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
- if (irq > 0 && irq_is_percpu(irq)) {
- /* If using PPIs, check the affinity of the partition */
- int ret;
+ nr_irqs = platform_irq_count(pdev);
+ if (nr_irqs < 0) {
+ pr_err("unable to count PMU IRQs\n");
+ return nr_irqs;
+ }
- ret = irq_get_percpu_devid_partition(irq, &pmu->supported_cpus);
- if (ret) {
- kfree(irqs);
- return ret;
- }
- } else {
- /* Otherwise default to all CPUs */
- cpumask_setall(&pmu->supported_cpus);
+ /*
+ * In this case we have no idea which CPUs are covered by the PMU.
+ * To match our prior behaviour, we assume all CPUs in this case.
+ */
+ if (nr_irqs == 0) {
+ pr_warn("no irqs for PMU, sampling events not supported\n");
+ cpumask_setall(&pmu->supported_cpus);
+ return 0;
+ }
+
+ if (nr_irqs == 1) {
+ int irq = platform_get_irq(pdev, 0);
+ if (irq && irq_is_percpu(irq)) {
+ return of_pmu_irq_cfg_ppi(pmu, irq);
}
}
- /* If we matched up the IRQ affinities, use them to route the SPIs */
- if (using_spi && i == pdev->num_resources)
- pmu->irq_affinity = irqs;
- else
- kfree(irqs);
+ for (i = 0; i < nr_irqs; i++) {
+ int cpu, irq;
+
+ irq = platform_get_irq(pdev, i);
+ if (WARN_ON(irq <= 0))
+ continue;
+
+ if (irq_is_percpu(irq)) {
+ pr_warn("multiple PPIs or mismatched SPI/PPI detected\n");
+ return -EINVAL;
+ }
+
+ cpu = of_pmu_parse_irq_affinity(pdev->dev.of_node, i);
+ if (cpu < 0)
+ return cpu;
+ if (cpu >= nr_cpu_ids)
+ continue;
+
+ if (per_cpu(hw_events->irq, cpu)) {
+ pr_warn("multiple PMU IRQs for the same CPU detected\n");
+ return -EINVAL;
+ }
+
+ per_cpu(hw_events->irq, cpu) = irq;
+ cpumask_set_cpu(cpu, &pmu->supported_cpus);
+ }
return 0;
}
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 8462da2..99dd863 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -75,6 +75,8 @@ struct pmu_hw_events {
* already have to allocate this struct per cpu.
*/
struct arm_pmu *percpu_pmu;
+
+ int irq;
};
enum armpmu_attr_groups {
--
1.9.1
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