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virtio: allow drivers to request IRQ affinity when creating VQs

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Add a struct irq_affinity pointer to the find_vqs methods, which if set
is used to tell the PCI layer to create the MSI-X vectors for our I/O
virtqueues with the proper affinity from the start.  Compared to after
the fact affinity hints this gives us an instantly working setup and
allows to allocate the irq descritors node-local and avoid interconnect
traffic.  Last but not least this will allow blk-mq queues are created
based on the interrupt affinity for storage drivers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Christoph Hellwig
2017-02-05 18:15:22 +01:00
committed by Michael S. Tsirkin
parent 52a6151612
commit fb5e31d970
20 changed files with 48 additions and 34 deletions
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19
drivers/virtio/virtio_pci_common.c
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@@ -143,22 +143,28 @@ void vp_del_vqs(struct virtio_device *vdev)
static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
struct virtqueue *vqs[], vq_callback_t *callbacks[],
const char * const names[])
const char * const names[], struct irq_affinity *desc)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
const char *name = dev_name(&vp_dev->vdev.dev);
int i, err = -ENOMEM, allocated_vectors, nvectors;
unsigned flags = PCI_IRQ_MSIX;
bool shared = false;
u16 msix_vec;
if (desc) {
flags |= PCI_IRQ_AFFINITY;
desc->pre_vectors++; /* virtio config vector */
}
nvectors = 1;
for (i = 0; i < nvqs; i++)
if (callbacks[i])
nvectors++;
/* Try one vector per queue first. */
err = pci_alloc_irq_vectors(vp_dev->pci_dev, nvectors, nvectors,
PCI_IRQ_MSIX);
err = pci_alloc_irq_vectors_affinity(vp_dev->pci_dev, nvectors,
nvectors, flags, desc);
if (err < 0) {
/* Fallback to one vector for config, one shared for queues. */
shared = true;
@@ -308,13 +314,12 @@ out_remove_vqs:
/* the config->find_vqs() implementation */
int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs,
struct virtqueue *vqs[],
vq_callback_t *callbacks[],
const char * const names[])
struct virtqueue *vqs[], vq_callback_t *callbacks[],
const char * const names[], struct irq_affinity *desc)
{
int err;
err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names);
err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names, desc);
if (!err)
return 0;
return vp_find_vqs_intx(vdev, nvqs, vqs, callbacks, names);