Re: [PATCH 08/11] megaraid_sas : Add module parameter to disable IRQ-CPU affinity hint

[Tomas Henzl <thenzl@redhat.com>]

On 09/06/2014 03:25 PM, Sumit.Saxena@avagotech.com wrote:
> For certain deployment, we may need to disable irq cpu affinity hint.
> This module parameter provides option for use to disable irq cpu affinity hint
> and allow irqbalancer to handle the rest.

Only curious , in which environments causes this which issues?

Thanks,
Tomas

>
> Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com>
> Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com>
> ---
>  drivers/scsi/megaraid/megaraid_sas_base.c | 60 +++++++++++++++++++------------
>  1 file changed, 38 insertions(+), 22 deletions(-) 
>
> diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
> index 07255c1..086beee 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_base.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_base.c
> @@ -89,6 +89,10 @@ module_param(resetwaittime, int, S_IRUGO);
>  MODULE_PARM_DESC(resetwaittime, "Wait time in seconds after I/O timeout "
>  		 "before resetting adapter. Default: 180");
>  
> +int smp_affinity_enable = 1;
> +module_param(smp_affinity_enable, int, S_IRUGO);
> +MODULE_PARM_DESC(smp_affinity_enable, "SMP affinity feature enable/disbale Default: enable(1)");
> +
>  MODULE_LICENSE("GPL");
>  MODULE_VERSION(MEGASAS_VERSION);
>  MODULE_AUTHOR("megaraidlinux@lsi.com");
> @@ -5160,8 +5164,9 @@ retry_irq_register:
>  				printk(KERN_DEBUG "megasas: Failed to "
>  				       "register IRQ for vector %d.\n", i);
>  				for (j = 0; j < i; j++) {
> -					irq_set_affinity_hint(
> -						instance->msixentry[j].vector, NULL);
> +					if (smp_affinity_enable)
> +						irq_set_affinity_hint(
> +							instance->msixentry[j].vector, NULL);
>  					free_irq(
>  						instance->msixentry[j].vector,
>  						&instance->irq_context[j]);
> @@ -5170,11 +5175,14 @@ retry_irq_register:
>  				instance->msix_vectors = 0;
>  				goto retry_irq_register;
>  			}
> -			if (irq_set_affinity_hint(instance->msixentry[i].vector,
> -				get_cpu_mask(cpu)))
> -				dev_err(&instance->pdev->dev, "Error setting"
> -					"affinity hint for cpu %d\n", cpu);
> -			cpu = cpumask_next(cpu, cpu_online_mask);
> +			if (smp_affinity_enable) {
> +				if (irq_set_affinity_hint(instance->msixentry[i].vector,
> +					get_cpu_mask(cpu)))
> +					dev_err(&instance->pdev->dev,
> +						"Error setting affinity hint "
> +						"for cpu %d\n", cpu);
> +				cpu = cpumask_next(cpu, cpu_online_mask);
> +			}
>  		}
>  	} else {
>  		instance->irq_context[0].instance = instance;
> @@ -5233,8 +5241,9 @@ retry_irq_register:
>  	instance->instancet->disable_intr(instance);
>  	if (instance->msix_vectors)
>  		for (i = 0; i < instance->msix_vectors; i++) {
> -			irq_set_affinity_hint(
> -				instance->msixentry[i].vector, NULL);
> +			if (smp_affinity_enable)
> +				irq_set_affinity_hint(
> +					instance->msixentry[i].vector, NULL);
>  			free_irq(instance->msixentry[i].vector,
>  				 &instance->irq_context[i]);
>  		}
> @@ -5397,8 +5406,9 @@ megasas_suspend(struct pci_dev *pdev, pm_message_t state)
>  
>  	if (instance->msix_vectors)
>  		for (i = 0; i < instance->msix_vectors; i++) {
> -			irq_set_affinity_hint(
> -				instance->msixentry[i].vector, NULL);
> +			if (smp_affinity_enable)
> +				irq_set_affinity_hint(
> +					instance->msixentry[i].vector, NULL);
>  			free_irq(instance->msixentry[i].vector,
>  				 &instance->irq_context[i]);
>  		}
> @@ -5507,8 +5517,9 @@ megasas_resume(struct pci_dev *pdev)
>  				printk(KERN_DEBUG "megasas: Failed to "
>  				       "register IRQ for vector %d.\n", i);
>  				for (j = 0; j < i; j++) {
> -					irq_set_affinity_hint(
> -						instance->msixentry[j].vector, NULL);
> +					if (smp_affinity_enable)
> +						irq_set_affinity_hint(
> +							instance->msixentry[j].vector, NULL);
>  					free_irq(
>  						instance->msixentry[j].vector,
>  						&instance->irq_context[j]);
> @@ -5516,11 +5527,14 @@ megasas_resume(struct pci_dev *pdev)
>  				goto fail_irq;
>  			}
>  
> -			if (irq_set_affinity_hint(instance->msixentry[i].vector,
> -				get_cpu_mask(cpu)))
> -				dev_err(&instance->pdev->dev, "Error setting"
> -					"affinity hint for cpu %d\n", cpu);
> -			cpu = cpumask_next(cpu, cpu_online_mask);
> +			if (smp_affinity_enable) {
> +				if (irq_set_affinity_hint(instance->msixentry[i].vector,
> +					get_cpu_mask(cpu)))
> +					dev_err(&instance->pdev->dev, "Error "
> +						"setting affinity hint for cpu "
> +						"%d\n", cpu);
> +				cpu = cpumask_next(cpu, cpu_online_mask);
> +			}
>  		}
>  	} else {
>  		instance->irq_context[0].instance = instance;
> @@ -5638,8 +5652,9 @@ static void megasas_detach_one(struct pci_dev *pdev)
>  
>  	if (instance->msix_vectors)
>  		for (i = 0; i < instance->msix_vectors; i++) {
> -			irq_set_affinity_hint(
> -				instance->msixentry[i].vector, NULL);
> +			if (smp_affinity_enable)
> +				irq_set_affinity_hint(
> +					instance->msixentry[i].vector, NULL);
>  			free_irq(instance->msixentry[i].vector,
>  				 &instance->irq_context[i]);
>  		}
> @@ -5727,8 +5742,9 @@ static void megasas_shutdown(struct pci_dev *pdev)
>  	instance->instancet->disable_intr(instance);
>  	if (instance->msix_vectors)
>  		for (i = 0; i < instance->msix_vectors; i++) {
> -			irq_set_affinity_hint(
> -				instance->msixentry[i].vector, NULL);
> +			if (smp_affinity_enable)
> +				irq_set_affinity_hint(
> +					instance->msixentry[i].vector, NULL);
>  			free_irq(instance->msixentry[i].vector,
>  				 &instance->irq_context[i]);
>  		}