[PATCH 5/8] arm: arm64: pmu: Assign platform PMU CPU affinity

[Jeremy Linton]

|-----Original Message-----
|From: Punit Agrawal [mailto:punit.agrawal at arm.com]
|Sent: Monday, June 20, 2016 11:41 AM
|To: Jeremy Linton
|Cc: linux-arm-kernel at lists.infradead.org; Mark Rutland; Lorenzo Pieralisi;
|mlangsdorf at redhat.com; peterz at infradead.org; Catalin Marinas; Will
|Deacon; acme at kernel.org; linux-acpi at vger.kernel.org;
|alexander.shishkin at linux.intel.com; mingo at redhat.com
|Subject: Re: [PATCH 5/8] arm: arm64: pmu: Assign platform PMU CPU affinity
|
|Jeremy Linton <jeremy.linton at arm.com> writes:
|
|> On systems with multiple PMU types the PMU to CPU affinity needs to be
|> detected and set. The CPU to interrupt affinity should also be set.
|>
|
|One comment below.
|
|> Signed-off-by: Jeremy Linton <jeremy.linton at arm.com>
|> ---
|>  drivers/perf/arm_pmu.c | 52
|++++++++++++++++++++++++++++++++++++++++----------
|>  1 file changed, 42 insertions(+), 10 deletions(-)
|>
|> diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
|> index fee4be0e8..865a9db 100644
|> --- a/drivers/perf/arm_pmu.c
|> +++ b/drivers/perf/arm_pmu.c
|
|[...]
|
|> @@ -872,25 +874,56 @@ static void cpu_pmu_destroy(struct arm_pmu
|*cpu_pmu)
|>  }
|>
|>  /*
|> - * CPU PMU identification and probing.
|> + * CPU PMU identification and probing. Its possible to have
|> + * multiple CPU types in an ARM machine. Assure that we are
|> + * picking the right PMU types based on the CPU in question
|>   */
|> -static int probe_current_pmu(struct arm_pmu *pmu,
|> -     const struct pmu_probe_info *info)
|> +static int probe_plat_pmu(struct arm_pmu *pmu,
|> +     const struct pmu_probe_info *info,
|> +     unsigned int pmuid)
|>  {
|> -int cpu = get_cpu();
|> -unsigned int cpuid = read_cpuid_id();
|>  int ret = -ENODEV;
|> +int cpu;
|> +int aff_ctr = 0;
|> +struct platform_device *pdev = pmu->plat_device;
|> +int irq = platform_get_irq(pdev, 0);
|>
|> -pr_info("probing PMU on CPU %d\n", cpu);
|> +if (irq >= 0 && !irq_is_percpu(irq)) {
|> +pmu->irq_affinity = kcalloc(pdev->num_resources,
|sizeof(int),
|> +    GFP_KERNEL);
|> +if (!pmu->irq_affinity)
|> +return -ENOMEM;
|> +}
|> +
|> +for_each_possible_cpu(cpu) {
|> +unsigned int cpuid = read_specific_cpuid(cpu);
|> +
|> +if (cpuid == pmuid) {
|> +cpumask_set_cpu(cpu, &pmu->supported_cpus);
|> +pr_devel("enable pmu on cpu %d\n", cpu);
|> +if (pmu->irq_affinity) {
|
|The check for irq_affinity can be dropped as you already do that earlier.

There isn't an irq_affinity structure for machines with PMU's using PPI's, that is why the check is there...

Thanks,

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