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[PATCH 7/8] pci: spread interrupt vectors in pci_alloc_irq_vectors

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  [PATCH 7/8] pci: spread interrupt vectors in pci_alloc_irq_vectors Christoph Hellwig <hch@lst.de> - 2016-04-16 03:40 +0200
    Re: [PATCH 7/8] pci: spread interrupt vectors in  pci_alloc_irq_vectors Thomas Gleixner <tglx@linutronix.de> - 2016-04-18 10:40 +0200

#1380463 — [PATCH 7/8] pci: spread interrupt vectors in pci_alloc_irq_vectors

Set the affinity_mask before allocating vectors.  And for now we also
need a little hack after allocation, hopefully someone smarter than me
can move this into the core code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/pci/irq.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/irq.c b/drivers/pci/irq.c
index b683465..d26df69 100644
--- a/drivers/pci/irq.c
+++ b/drivers/pci/irq.c
@@ -55,9 +55,14 @@ int pci_alloc_irq_vectors(struct pci_dev *pdev, int nr_vecs)
 
 	nr_vecs = min(nr_vecs, pci_nr_irq_vectors(pdev));
 
+	ret = irq_create_affinity_mask(&pdev->dev.irq_affinity, nr_vecs);
+	if (ret)
+		return ret;
+
+	ret = -ENOMEM;
 	irqs = kcalloc(nr_vecs, sizeof(u32), GFP_KERNEL);
 	if (!irqs)
-		return -ENOMEM;
+		goto out_free_affinity;
 
 	vecs = pci_enable_msix_range_wrapper(pdev, irqs, nr_vecs);
 	if (vecs <= 0) {
@@ -75,11 +80,20 @@ int pci_alloc_irq_vectors(struct pci_dev *pdev, int nr_vecs)
 			irqs[i] = pdev->irq + i;
 	}
 
+	/* XXX: this should really move into the core IRQ allocation code.. */
+	if (vecs > 1) {
+		for (i = 0; i < vecs; i++)
+			irq_program_affinity(irqs[i]);
+	}
+
 	pdev->irqs = irqs;
 	return vecs;
 
 out_free_irqs:
 	kfree(irqs);
+out_free_affinity:
+	kfree(pdev->dev.irq_affinity);
+	pdev->dev.irq_affinity = NULL;
 	return ret;
 }
 EXPORT_SYMBOL(pci_alloc_irq_vectors);
-- 
2.1.4

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#1381372 — Re: [PATCH 7/8] pci: spread interrupt vectors in pci_alloc_irq_vectors

On Fri, 15 Apr 2016, Christoph Hellwig wrote:
> Set the affinity_mask before allocating vectors.  And for now we also
> need a little hack after allocation, hopefully someone smarter than me
> can move this into the core code.
> 
>  
> +	/* XXX: this should really move into the core IRQ allocation code.. */
> +	if (vecs > 1) {
> +		for (i = 0; i < vecs; i++)
> +			irq_program_affinity(irqs[i]);

No. We don't want to do that at allocation time. The problem here is that we
set the IRQF_NOBALANCING flag for the allocated interrupts and therefor the
affinity is not set from request_irq(). We'll fix it there.

Thanks,

	tglx

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