diff mbox

[7/8] arm: perf: dynamically allocate cpu hardware data

Message ID 1413897084-19715-8-git-send-email-mark.rutland@arm.com
State New
Headers show

Commit Message

Mark Rutland Oct. 21, 2014, 1:11 p.m. UTC 
To support multiple PMUs, each PMU will need its own accounting data.
As we don't know how (in general) many PMUs we'll have to support at
compile-time, we must allocate the data at runtime dynamically

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
---
 arch/arm/kernel/perf_event_cpu.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

Comments

Stephen Boyd Oct. 21, 2014, 9:24 p.m. UTC | #1 
On 10/21/2014 06:11 AM, Mark Rutland wrote:
> @@ -162,16 +160,22 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
>  	return 0;
>  }
>  
> -static void cpu_pmu_init(struct arm_pmu *cpu_pmu)
> +static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
>  {
>  	int cpu;
> +	struct pmu_hw_events __percpu *cpu_hw_events;
> +
> +	cpu_hw_events = alloc_percpu(struct pmu_hw_events);

Shouldn't we free this somewhere?

> +	if (!cpu_hw_events)
> +		return -ENOMEM;
> +
>  	for_each_possible_cpu(cpu) {
> -		struct pmu_hw_events *events = &per_cpu(cpu_hw_events, cpu);
> +		struct pmu_hw_events *events = per_cpu_ptr(cpu_hw_events, cpu);
>  		raw_spin_lock_init(&events->pmu_lock);
>  		events->percpu_pmu = cpu_pmu;
>  	}
>  
> -	cpu_pmu->hw_events	= &cpu_hw_events;
> +	cpu_pmu->hw_events	= cpu_hw_events;
>  	cpu_pmu->request_irq	= cpu_pmu_request_irq;
>  	cpu_pmu->free_irq	= cpu_pmu_free_irq;
>  
> @@ -303,7 +309,10 @@ static int cpu_pmu_device_probe(struct platform_device *pdev)
>  		goto out_free;
>  	}
>  
> -	cpu_pmu_init(cpu_pmu);
> +	ret = cpu_pmu_init(cpu_pmu);
> +	if (ret)
> +		goto out_free;
> +
>  	ret = armpmu_register(cpu_pmu, -1);
>  
>  	if (!ret)

Especially if this fails?
Mark Rutland Oct. 22, 2014, 11:06 a.m. UTC | #2 
On Tue, Oct 21, 2014 at 10:24:54PM +0100, Stephen Boyd wrote:
> On 10/21/2014 06:11 AM, Mark Rutland wrote:
> > @@ -162,16 +160,22 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
> >  	return 0;
> >  }
> >  
> > -static void cpu_pmu_init(struct arm_pmu *cpu_pmu)
> > +static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
> >  {
> >  	int cpu;
> > +	struct pmu_hw_events __percpu *cpu_hw_events;
> > +
> > +	cpu_hw_events = alloc_percpu(struct pmu_hw_events);
> 
> Shouldn't we free this somewhere?

My bad. We should clean this up if registration fails. As we don't
support unregistering PMUs, that should be the only case where we'll
need to free this.

I'll wrap that up in a new cpu_pmu_destroy function, which we can also
use to tear down the notifier introduced in the next patch.

Thanks,
Mark.

> 
> > +	if (!cpu_hw_events)
> > +		return -ENOMEM;
> > +
> >  	for_each_possible_cpu(cpu) {
> > -		struct pmu_hw_events *events = &per_cpu(cpu_hw_events, cpu);
> > +		struct pmu_hw_events *events = per_cpu_ptr(cpu_hw_events, cpu);
> >  		raw_spin_lock_init(&events->pmu_lock);
> >  		events->percpu_pmu = cpu_pmu;
> >  	}
> >  
> > -	cpu_pmu->hw_events	= &cpu_hw_events;
> > +	cpu_pmu->hw_events	= cpu_hw_events;
> >  	cpu_pmu->request_irq	= cpu_pmu_request_irq;
> >  	cpu_pmu->free_irq	= cpu_pmu_free_irq;
> >  
> > @@ -303,7 +309,10 @@ static int cpu_pmu_device_probe(struct platform_device *pdev)
> >  		goto out_free;
> >  	}
> >  
> > -	cpu_pmu_init(cpu_pmu);
> > +	ret = cpu_pmu_init(cpu_pmu);
> > +	if (ret)
> > +		goto out_free;
> > +
> >  	ret = armpmu_register(cpu_pmu, -1);
> >  
> >  	if (!ret)
> 
> Especially if this fails?
> 
> -- 
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 
>
diff mbox

Patch

diff --git a/arch/arm/kernel/perf_event_cpu.c b/arch/arm/kernel/perf_event_cpu.c
index cd95388..f8a237d 100644
--- a/arch/arm/kernel/perf_event_cpu.c
+++ b/arch/arm/kernel/perf_event_cpu.c
@@ -35,8 +35,6 @@ 
 /* Set at runtime when we know what CPU type we are. */
 static struct arm_pmu *cpu_pmu;
 
-static DEFINE_PER_CPU(struct pmu_hw_events, cpu_hw_events);
-
 /*
  * Despite the names, these two functions are CPU-specific and are used
  * by the OProfile/perf code.
@@ -162,16 +160,22 @@  static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
 	return 0;
 }
 
-static void cpu_pmu_init(struct arm_pmu *cpu_pmu)
+static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
 {
 	int cpu;
+	struct pmu_hw_events __percpu *cpu_hw_events;
+
+	cpu_hw_events = alloc_percpu(struct pmu_hw_events);
+	if (!cpu_hw_events)
+		return -ENOMEM;
+
 	for_each_possible_cpu(cpu) {
-		struct pmu_hw_events *events = &per_cpu(cpu_hw_events, cpu);
+		struct pmu_hw_events *events = per_cpu_ptr(cpu_hw_events, cpu);
 		raw_spin_lock_init(&events->pmu_lock);
 		events->percpu_pmu = cpu_pmu;
 	}
 
-	cpu_pmu->hw_events	= &cpu_hw_events;
+	cpu_pmu->hw_events	= cpu_hw_events;
 	cpu_pmu->request_irq	= cpu_pmu_request_irq;
 	cpu_pmu->free_irq	= cpu_pmu_free_irq;
 
@@ -182,6 +186,8 @@  static void cpu_pmu_init(struct arm_pmu *cpu_pmu)
 	/* If no interrupts available, set the corresponding capability flag */
 	if (!platform_get_irq(cpu_pmu->plat_device, 0))
 		cpu_pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
+
+	return 0;
 }
 
 /*
@@ -303,7 +309,10 @@  static int cpu_pmu_device_probe(struct platform_device *pdev)
 		goto out_free;
 	}
 
-	cpu_pmu_init(cpu_pmu);
+	ret = cpu_pmu_init(cpu_pmu);
+	if (ret)
+		goto out_free;
+
 	ret = armpmu_register(cpu_pmu, -1);
 
 	if (!ret)