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From: Laurent Vivier <lvivier@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: linux-block@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
	linux-pci@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
	Marc Zyngier <maz@kernel.org>,
	linuxppc-dev@lists.ozlabs.org,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	"Michael S . Tsirkin" <mst@redhat.com>,
	Greg Kurz <groug@kaod.org>, Christoph Hellwig <hch@lst.de>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Laurent Vivier <lvivier@redhat.com>
Subject: [PATCH v2 2/2] powerpc/pseries: pass MSI affinity to irq_create_mapping()
Date: Wed, 25 Nov 2020 12:16:57 +0100	[thread overview]
Message-ID: <20201125111657.1141295-3-lvivier@redhat.com> (raw)
In-Reply-To: <20201125111657.1141295-1-lvivier@redhat.com>

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

But since commit 0d9f0a52c8b9f ("virtio_scsi: use virtio IRQ affinity")
this is broken on pseries.

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 <lvivier@redhat.com>
---
 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


  parent reply	other threads:[~2020-11-25 11:17 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-25 11:16 [PATCH v2 0/2] powerpc/pseries: fix MSI/X IRQ affinity on pseries Laurent Vivier
2020-11-25 11:16 ` [PATCH v2 1/2] genirq: add an irq_create_mapping_affinity() function Laurent Vivier
2020-11-25 12:45   ` Greg Kurz
2020-11-25 13:20   ` Thomas Gleixner
2020-11-25 14:09     ` Laurent Vivier
2020-11-25 14:54       ` Marc Zyngier
2020-11-25 15:00         ` Laurent Vivier
2020-11-25 11:16 ` Laurent Vivier [this message]
2020-11-25 12:51   ` [PATCH v2 2/2] powerpc/pseries: pass MSI affinity to irq_create_mapping() Greg Kurz

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