Hi Keith
Thanks for your time and patch for this.
On 03/24/2018 06:19 AM, Keith Busch wrote:
> The PCI interrupt vectors intended to be associated with a queue may
> not start at 0. This patch adds an offset parameter so blk-mq may find
> the intended affinity mask. The default value is 0 so existing drivers
> that don't care about this parameter don't need to change.
>
> Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx>
> ---
> block/blk-mq-pci.c | 12 ++++++++++--
> include/linux/blk-mq-pci.h | 2 ++
> 2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/block/blk-mq-pci.c b/block/blk-mq-pci.c
> index 76944e3271bf..1040a7705c13 100644
> --- a/block/blk-mq-pci.c
> +++ b/block/blk-mq-pci.c
> @@ -21,6 +21,7 @@
> * blk_mq_pci_map_queues - provide a default queue mapping for PCI device
> * @set: tagset to provide the mapping for
> * @pdev: PCI device associated with @set.
> + * @offset: PCI irq starting vector offset
> *
> * This function assumes the PCI device @pdev has at least as many available
> * interrupt vectors as @set has queues. It will then query the vector
> @@ -28,13 +29,14 @@
> * that maps a queue to the CPUs that have irq affinity for the corresponding
> * vector.
> */
> -int blk_mq_pci_map_queues(struct blk_mq_tag_set *set, struct pci_dev *pdev)
> +int __blk_mq_pci_map_queues(struct blk_mq_tag_set *set, struct pci_dev *pdev,
> + int offset)
> {
> const struct cpumask *mask;
> unsigned int queue, cpu;
>
> for (queue = 0; queue < set->nr_hw_queues; queue++) {
> - mask = pci_irq_get_affinity(pdev, queue);
> + mask = pci_irq_get_affinity(pdev, queue + offset);
> if (!mask)
> goto fallback;
>
Maybe we could provide a callback parameter for __blk_mq_pci_map_queues which
give the mapping from hctx queue num to device-relative interrupt vector index.
Thanks
Jianchao
