> This is the wrong direction as it does not allow to do initial affinity
> assignement for the non-managed interrupts on allocation time. And
that's
> what Kashyap and Sumit are looking for.
>
> The trivial fix for the possible breakage when irq_default_affinity !=
> cpu_possible_mask is to set the affinity for the pre/post vectors to
> cpu_possible_mask and be done with it.
>
> One other thing I noticed while staring at that is the fact, that the
PCI
> code does not care about the return value of irq_create_affinity_masks()
at
> all. It just proceeds if masks is NULL as if the stuff was requested
with
> the affinity descriptor pointer being NULL. I don't think that's a
> brilliant idea because the drivers might rely on the interrupt being
> managed, but it might be a non-issue and just result in bad locality.
>
> Christoph?
>
> So back to the problem at hand. We need to change the affinity
management
> scheme in a way which lets us differentiate between managed and
> unmanaged
> interrupts, so it allows to automatically assign (initial) affinity to
all
> of them.
>
> Right now everything is bound to the cpumasks array, which does not
allow
> to convey more information. So we need to come up with something
> different.
>
> Something like the below (does not compile and is just for reference)
> should do the trick. I'm not sure whether we want to convey the
information
> (masks and bitmap) in a single data structure or not, but that's an
> implementation detail.
Dou - Do you want me to test your patch or shall I wait for next version
?
>
> Thanks,
>
> tglx
>
> 8<---------
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -535,15 +535,16 @@ static struct msi_desc *
> msi_setup_entry(struct pci_dev *dev, int nvec, const struct
irq_affinity *affd)
> {
> struct cpumask *masks = NULL;
> + unsigned long managed = 0;
> struct msi_desc *entry;
> u16 control;
>
> if (affd)
> - masks = irq_create_affinity_masks(nvec, affd);
> + masks = irq_create_affinity_masks(nvec, affd, &managed);
>
>
> /* MSI Entry Initialization */
> - entry = alloc_msi_entry(&dev->dev, nvec, masks);
> + entry = alloc_msi_entry(&dev->dev, nvec, masks, managed);
> if (!entry)
> goto out;
>
> @@ -672,15 +673,22 @@ static int msix_setup_entries(struct pci
> struct msix_entry *entries, int nvec,
> const struct irq_affinity *affd)
> {
> + /*
> + * MSIX_MAX_VECTORS = 2048, i.e. 256 bytes. Might need runtime
> + * allocation. OTOH, are 2048 vectors realistic?
> + */
> + DECLARE_BITMAP(managed, MSIX_MAX_VECTORS);
> struct cpumask *curmsk, *masks = NULL;
> struct msi_desc *entry;
> int ret, i;
>
> if (affd)
> - masks = irq_create_affinity_masks(nvec, affd);
> + masks = irq_create_affinity_masks(nvec, affd, managed);
>
> for (i = 0, curmsk = masks; i < nvec; i++) {
> - entry = alloc_msi_entry(&dev->dev, 1, curmsk);
> + unsigned long m = test_bit(i, managed) ? 1 : 0;
> +
> + entry = alloc_msi_entry(&dev->dev, 1, curmsk, m);
> if (!entry) {
> if (!i)
> iounmap(base);
> --- a/kernel/irq/msi.c
> +++ b/kernel/irq/msi.c
> @@ -27,7 +27,8 @@
> * and the affinity masks from @affinity are copied.
> */
> struct msi_desc *
> -alloc_msi_entry(struct device *dev, int nvec, const struct cpumask
*affinity)
> +alloc_msi_entry(struct device *dev, int nvec, const struct cpumask
*affinity,
> + unsigned long managed)
> {
> struct msi_desc *desc;
>
> @@ -38,6 +39,7 @@ alloc_msi_entry(struct device *dev, int
> INIT_LIST_HEAD(&desc->list);
> desc->dev = dev;
> desc->nvec_used = nvec;
> + desc->managed = managed;
> if (affinity) {
> desc->affinity = kmemdup(affinity,
> nvec * sizeof(*desc->affinity), GFP_KERNEL);
> @@ -416,7 +418,7 @@ int msi_domain_alloc_irqs(struct irq_dom
>
> virq = __irq_domain_alloc_irqs(domain, -1,
desc->nvec_used,
> dev_to_node(dev), &arg,
false,
> - desc->affinity);
> + desc->affinity,
desc->managed);
> if (virq < 0) {
> ret = -ENOSPC;
> if (ops->handle_error)
