Messages in this thread |  | | Date | Mon, 18 Nov 2013 19:48:31 +0530 | Subject | Re: [PATCH V3 2/2] arm64: perf: add support for percpu pmu interrupt | From | Vinayak Kale <> |
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On Mon, Nov 18, 2013 at 7:16 PM, Marc Zyngier <marc.zyngier@arm.com> wrote: > Vinayak, > > > On 2013-11-18 13:22, Vinayak Kale wrote: >> >> 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 | 102 >> +++++++++++++++++++++++++++++----------- >> 1 file changed, 74 insertions(+), 28 deletions(-) >> >> diff --git a/arch/arm64/kernel/perf_event.c >> b/arch/arm64/kernel/perf_event.c >> index cea1594..23475f6 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 +364,51 @@ 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()); >> + 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 (irq_to_desc(irq) && irq_is_percpu(irq)) { > > > Why do you need to check the irq_desc here? It really looks like a misuse of > the API. I don't think it's being misused. In case of invalid irq number, the API would return null. > Instead, you should check the value of irq itself (it should be strictly > positive). > > >> + on_each_cpu(armpmu_disable_percpu_irq, 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) > > > irq == 0 means "no-irq". You should handle it as an error case. This part of the code (for non-percpu irq) was already present in driver as is. Will was Okay with it as per his review on V1 here: http://lists.infradead.org/pipermail/linux-arm-kernel/2013-November/210102.html > > >> + 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 +426,50 @@ 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; >> - } >> + if (irq_to_desc(irq) && irq_is_percpu(irq)) { > > > Same comment about irq_to_desc. > > >> + 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) > > > Same comment about irq == 0. This part of the code (for non-percpu irq) was already present in driver as is. Will was Okay with it as per his review on V1 here: http://lists.infradead.org/pipermail/linux-arm-kernel/2013-November/210102.html > > >> + 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; > > > -- > Fast, cheap, reliable. Pick two. > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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