Re: [PATCH 4/4] powerpc/perf: Unregister thread-imc if core-imc not supported

[Madhavan Srinivasan <maddy@linux.vnet.ibm.com>]

On Monday 09 April 2018 02:30 PM, Anju T Sudhakar wrote:
> Enable thread-imc in the kernel, only if core-imc is registered.

Can you add more info here? Why we need this and so on.

> Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
> ---
>   arch/powerpc/include/asm/imc-pmu.h        |  1 +
>   arch/powerpc/perf/imc-pmu.c               | 12 ++++++++++++
>   arch/powerpc/platforms/powernv/opal-imc.c |  9 +++++++++
>   3 files changed, 22 insertions(+)
>
> diff --git a/arch/powerpc/include/asm/imc-pmu.h b/arch/powerpc/include/asm/imc-pmu.h
> index d76cb11..69f516e 100644
> --- a/arch/powerpc/include/asm/imc-pmu.h
> +++ b/arch/powerpc/include/asm/imc-pmu.h
> @@ -128,4 +128,5 @@ extern int init_imc_pmu(struct device_node *parent,
>   				struct imc_pmu *pmu_ptr, int pmu_id);
>   extern void thread_imc_disable(void);
>   extern int get_max_nest_dev(void);
> +extern void unregister_thread_imc(void);
>   #endif /* __ASM_POWERPC_IMC_PMU_H */
> diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
> index 4b4ca83..fa88785 100644
> --- a/arch/powerpc/perf/imc-pmu.c
> +++ b/arch/powerpc/perf/imc-pmu.c
> @@ -40,6 +40,7 @@ static struct imc_pmu *core_imc_pmu;
>   /* Thread IMC data structures and variables */
>
>   static DEFINE_PER_CPU(u64 *, thread_imc_mem);
> +static struct imc_pmu *thread_imc_pmu;
>   static int thread_imc_mem_size;
>
>   struct imc_pmu *imc_event_to_pmu(struct perf_event *event)
> @@ -1228,6 +1229,16 @@ static void imc_common_cpuhp_mem_free(struct imc_pmu *pmu_ptr)
>   	}
>   }
>
> +/*
> + * Function to unregister thread-imc if core-imc
> + * is not registered.
> + */
> +void unregister_thread_imc(void)
> +{
> +	imc_common_cpuhp_mem_free(thread_imc_pmu);
> +	imc_common_mem_free(thread_imc_pmu);
> +	perf_pmu_unregister(&thread_imc_pmu->pmu);
> +}
>
>   /*
>    * imc_mem_init : Function to support memory allocation for core imc.
> @@ -1296,6 +1307,7 @@ static int imc_mem_init(struct imc_pmu *pmu_ptr, struct device_node *parent,
>   			}
>   		}
>
> +		thread_imc_pmu = pmu_ptr;
>   		break;
>   	default:
>   		return -EINVAL;
> diff --git a/arch/powerpc/platforms/powernv/opal-imc.c b/arch/powerpc/platforms/powernv/opal-imc.c
> index 490bb72..58a0794 100644
> --- a/arch/powerpc/platforms/powernv/opal-imc.c
> +++ b/arch/powerpc/platforms/powernv/opal-imc.c
> @@ -255,6 +255,7 @@ static int opal_imc_counters_probe(struct platform_device *pdev)
>   {
>   	struct device_node *imc_dev = pdev->dev.of_node;
>   	int pmu_count = 0, domain;
> +	bool core_imc_reg = false, thread_imc_reg = false;
>   	u32 type;
>
>   	/*
> @@ -292,6 +293,10 @@ static int opal_imc_counters_probe(struct platform_device *pdev)
>   		if (!imc_pmu_create(imc_dev, pmu_count, domain)) {
>   			if (domain == IMC_DOMAIN_NEST)
>   				pmu_count++;
> +			if (domain == IMC_DOMAIN_CORE)
> +				core_imc_reg = true;
> +			if (domain == IMC_DOMAIN_THREAD)
> +				thread_imc_reg = true;
>   		}
>   	}
>
> @@ -299,6 +304,10 @@ static int opal_imc_counters_probe(struct platform_device *pdev)
>   	if (pmu_count == 0)
>   		debugfs_remove_recursive(imc_debugfs_parent);
>
> +	/* If core imc is not registered, unregister thread-imc */
> +	if (!core_imc_reg && thread_imc_reg)
> +		unregister_thread_imc();
> +
>   	return 0;
>   }
>