by Martin K. Petersen

[permalink] [raw]

Subject: Re: [PATCH v5 00/14] genirq: Cleanup the abuse of irq_set_affinity_hint()

Nitesh,

> Gentle ping.
> Any comments on the following patches:
>
> scsi: megaraid_sas: Use irq_set_affinity_and_hint
> scsi: mpt3sas: Use irq_set_affinity_and_hint

Sumit and Sreekanth: Please review.

Thanks!

--
Martin K. Petersen Oracle Linux Engineering

2021-08-06 08:57:08

by Sreekanth Reddy

[permalink] [raw]

Subject: Re: [PATCH v5 05/14] scsi: mpt3sas: Use irq_set_affinity_and_hint

On Wed, Jul 21, 2021 at 4:57 AM Nitesh Narayan Lal <[email protected]> wrote:
>
> The driver uses irq_set_affinity_hint() specifically for the high IOPS
> queue interrupts for two purposes:
>
> - To set the affinity_hint which is consumed by the userspace for
> distributing the interrupts
>
> - To apply an affinity that it provides
>
> The driver enforces its own affinity to bind the high IOPS queue interrupts
> to the local NUMA node. However, irq_set_affinity_hint() applying the
> provided cpumask as an affinity (if not NULL) for the interrupt is an
> undocumented side effect.
>
> To remove this side effect irq_set_affinity_hint() has been marked
> as deprecated and new interfaces have been introduced. Hence, replace the
> irq_set_affinity_hint() with the new interface irq_set_affinity_and_hint()
> where the provided mask needs to be applied as the affinity and
> affinity_hint pointer needs to be set and replace with
> irq_update_affinity_hint() where only affinity_hint needs to be updated.
>

Changes looks good and also verified that the high iops queue's IRQs
are affinitied to local numa node.

Reviewed-by: Sreekanth Reddy <[email protected]>
> Signed-off-by: Nitesh Narayan Lal <[email protected]>
> ---
> drivers/scsi/mpt3sas/mpt3sas_base.c | 21 ++++++++++-----------
> 1 file changed, 10 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
> index c39955239d1c..c1a11962f227 100644
> --- a/drivers/scsi/mpt3sas/mpt3sas_base.c
> +++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
> @@ -2991,6 +2991,7 @@ _base_check_enable_msix(struct MPT3SAS_ADAPTER *ioc)
> static void
> _base_free_irq(struct MPT3SAS_ADAPTER *ioc)
> {
> + unsigned int irq;
> struct adapter_reply_queue *reply_q, *next;
>
> if (list_empty(&ioc->reply_queue_list))
> @@ -2998,9 +2999,10 @@ _base_free_irq(struct MPT3SAS_ADAPTER *ioc)
>
> list_for_each_entry_safe(reply_q, next, &ioc->reply_queue_list, list) {
> list_del(&reply_q->list);
> - if (ioc->smp_affinity_enable)
> - irq_set_affinity_hint(pci_irq_vector(ioc->pdev,
> - reply_q->msix_index), NULL);
> + if (ioc->smp_affinity_enable) {
> + irq = pci_irq_vector(ioc->pdev, reply_q->msix_index);
> + irq_update_affinity_hint(irq, NULL);
> + }
> free_irq(pci_irq_vector(ioc->pdev, reply_q->msix_index),
> reply_q);
> kfree(reply_q);
> @@ -3056,16 +3058,13 @@ _base_request_irq(struct MPT3SAS_ADAPTER *ioc, u8 index)
> * @ioc: per adapter object
> *
> * The enduser would need to set the affinity via /proc/irq/#/smp_affinity
> - *
> - * It would nice if we could call irq_set_affinity, however it is not
> - * an exported symbol
> */
> static void
> _base_assign_reply_queues(struct MPT3SAS_ADAPTER *ioc)
> {
> - unsigned int cpu, nr_cpus, nr_msix, index = 0;
> + unsigned int cpu, nr_cpus, nr_msix, index = 0, irq;
> struct adapter_reply_queue *reply_q;
> - int local_numa_node;
> + const struct cpumask *mask;
>
> if (!_base_is_controller_msix_enabled(ioc))
> return;
> @@ -3088,11 +3087,11 @@ _base_assign_reply_queues(struct MPT3SAS_ADAPTER *ioc)
> * corresponding to high iops queues.
> */
> if (ioc->high_iops_queues) {
> - local_numa_node = dev_to_node(&ioc->pdev->dev);
> + mask = cpumask_of_node(dev_to_node(&ioc->pdev->dev));
> for (index = 0; index < ioc->high_iops_queues;
> index++) {
> - irq_set_affinity_hint(pci_irq_vector(ioc->pdev,
> - index), cpumask_of_node(local_numa_node));
> + irq = pci_irq_vector(ioc->pdev, index);
> + irq_set_affinity_and_hint(irq, mask);
> }
> }
>
> --
> 2.27.0
>

Attachments:

smime.p7s (4.12 kB)
S/MIME Cryptographic Signature