Thread (26 messages) flat view 26 messages, 9 authors, 2021-08-30

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

From: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Date: 2021-08-06 08:55:07
Also in: intel-wired-lan, linux-api, linux-pci, linux-scsi, lkml

On Wed, Jul 21, 2021 at 4:57 AM Nitesh Narayan Lal [off-list ref] 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 <sreekanth.reddy@broadcom.com>
quoted hunk ↗ jump to hunk
Signed-off-by: Nitesh Narayan Lal <redacted>
---
 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

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