2020-11-27 04:16:39

by Laurent Vivier

Subject: [PATCH v4 2/2] powerpc/pseries: Pass MSI affinity to irq_create_mapping()

With virtio multiqueue, normally each queue IRQ is mapped to a CPU.

Commit 0d9f0a52c8b9f ("virtio_scsi: use virtio IRQ affinity") exposed
an existing shortcoming of the arch code by moving virtio_scsi to
the automatic IRQ affinity assignment.

The affinity is correctly computed in msi_desc but this is not applied
to the system IRQs.

It appears the affinity is correctly passed to rtas_setup_msi_irqs() but
lost at this point and never passed to irq_domain_alloc_descs()
(see commit 06ee6d571f0e ("genirq: Add affinity hint to irq allocation"))
because irq_create_mapping() doesn't take an affinity parameter.

As the previous patch has added the affinity parameter to
irq_create_mapping() we can forward the affinity from rtas_setup_msi_irqs()
to irq_domain_alloc_descs().

With this change, the virtqueues are correctly dispatched between the CPUs
on pseries.

Signed-off-by: Laurent Vivier <[email protected]>
Reviewed-by: Greg Kurz <[email protected]>
Acked-by: Michael Ellerman <[email protected]>
---
arch/powerpc/platforms/pseries/msi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/msi.c b/arch/powerpc/platforms/pseries/msi.c
index 133f6adcb39c..b3ac2455faad 100644
--- a/arch/powerpc/platforms/pseries/msi.c
+++ b/arch/powerpc/platforms/pseries/msi.c
@@ -458,7 +458,8 @@ static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec_in, int type)
return hwirq;
}

- virq = irq_create_mapping(NULL, hwirq);
+ virq = irq_create_mapping_affinity(NULL, hwirq,
+ entry->affinity);

if (!virq) {
pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq);
--
2.28.0

2020-11-30 11:32:51

by tip-bot2 for Haifeng Xu

Subject: [tip: irq/urgent] powerpc/pseries: Pass MSI affinity to irq_create_mapping()

The following commit has been merged into the irq/urgent branch of tip:

Commit-ID: 9ea69a55b3b9a71cded9726af591949c1138f235
Gitweb: https://git.kernel.org/tip/9ea69a55b3b9a71cded9726af591949c1138f235
Author: Laurent Vivier <[email protected]>
AuthorDate: Thu, 26 Nov 2020 09:28:52 +01:00
Committer: Thomas Gleixner <[email protected]>
CommitterDate: Mon, 30 Nov 2020 12:22:04 +01:00

powerpc/pseries: Pass MSI affinity to irq_create_mapping()

With virtio multiqueue, normally each queue IRQ is mapped to a CPU.

Commit 0d9f0a52c8b9f ("virtio_scsi: use virtio IRQ affinity") exposed
an existing shortcoming of the arch code by moving virtio_scsi to
the automatic IRQ affinity assignment.

The affinity is correctly computed in msi_desc but this is not applied
to the system IRQs.

It appears the affinity is correctly passed to rtas_setup_msi_irqs() but
lost at this point and never passed to irq_domain_alloc_descs()
(see commit 06ee6d571f0e ("genirq: Add affinity hint to irq allocation"))
because irq_create_mapping() doesn't take an affinity parameter.

Use the new irq_create_mapping_affinity() function, which allows to forward
the affinity setting from rtas_setup_msi_irqs() to irq_domain_alloc_descs().

With this change, the virtqueues are correctly dispatched between the CPUs
on pseries.

Fixes: e75eafb9b039 ("genirq/msi: Switch to new irq spreading infrastructure")
Signed-off-by: Laurent Vivier <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Greg Kurz <[email protected]>
Acked-by: Michael Ellerman <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
---
arch/powerpc/platforms/pseries/msi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/msi.c b/arch/powerpc/platforms/pseries/msi.c
index 133f6ad..b3ac245 100644
--- a/arch/powerpc/platforms/pseries/msi.c
+++ b/arch/powerpc/platforms/pseries/msi.c
@@ -458,7 +458,8 @@ again:
return hwirq;
}

- virq = irq_create_mapping(NULL, hwirq);
+ virq = irq_create_mapping_affinity(NULL, hwirq,
+ entry->affinity);

if (!virq) {
pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq);