Re: [PATCH V6 2/2] arm64: perf: add support for percpu pmu interrupt

From: Vinayak Kale
Date: Wed Dec 04 2013 - 01:26:33 EST


On Tue, Dec 3, 2013 at 7:20 PM, Will Deacon <will.deacon@xxxxxxx> wrote:
> On Mon, Dec 02, 2013 at 09:34:03AM +0000, Vinayak Kale wrote:
>> 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);
>
> Why not just cpumask_clear_cpu?

Yes, that would have serve the purpose. It was due to dumb copy/paste
from non-percpu counterpart.

>
>> + disable_percpu_irq(irq);
>> +}
>> +
>> +static void
>> armpmu_release_hardware(struct arm_pmu *armpmu)
>> {
>> - int i, irq, irqs;
>> + int irq;
>> + unsigned int i, irqs;
>> struct platform_device *pmu_device = armpmu->plat_device;
>>
>> irqs = min(pmu_device->num_resources, num_possible_cpus());
>> + if (!irqs)
>> + 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, IRQ_TYPE_NONE);
>> + cpumask_set_cpu(smp_processor_id(), &armpmu->active_irqs);
>
> Hmm, wouldn't it make more sense to pass the irq in data, then deal with the
> mask in the caller? (since the mask will *always* be updated by each CPU).
>
> Similarly for the disable path.

Okay.
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