On Tue, Mar 27, 2018 at 09:39:08AM -0600, Keith Busch wrote: > The admin and first IO queues shared the first irq vector, which has an > affinity mask including cpu0. If a system allows cpu0 to be offlined, > the admin queue may not be usable if no other CPUs in the affinity mask > are online. This is a problem since unlike IO queues, there is only > one admin queue that always needs to be usable. > > To fix, this patch allocates one pre_vector for the admin queue that > is assigned all CPUs, so will always be accessible. The IO queues are > assigned the remaining managed vectors. > > In case a controller has only one interrupt vector available, the admin > and IO queues will share the pre_vector with all CPUs assigned. > > Cc: Jianchao Wang <jianchao.w.wang@xxxxxxxxxx> > Cc: Ming Lei <ming.lei@xxxxxxxxxx> > Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx> > --- > v1 -> v2: > > Update to use new blk-mq API. > > Removed unnecessary braces, inline functions, and temp variables. > > Amended author (this has evolved significantly from the original). > > drivers/nvme/host/pci.c | 23 +++++++++++++++++------ > 1 file changed, 17 insertions(+), 6 deletions(-) > > diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c > index cc47fbe32ea5..50c8eaf51d92 100644 > --- a/drivers/nvme/host/pci.c > +++ b/drivers/nvme/host/pci.c > @@ -84,6 +84,7 @@ struct nvme_dev { > struct dma_pool *prp_small_pool; > unsigned online_queues; > unsigned max_qid; > + unsigned int num_vecs; > int q_depth; > u32 db_stride; > void __iomem *bar; > @@ -414,7 +415,8 @@ static int nvme_pci_map_queues(struct blk_mq_tag_set *set) > { > struct nvme_dev *dev = set->driver_data; > > - return blk_mq_pci_map_queues(set, to_pci_dev(dev->dev), 0); > + return blk_mq_pci_map_queues(set, to_pci_dev(dev->dev), > + dev->num_vecs > 1); > } > > /** > @@ -1455,7 +1457,11 @@ static int nvme_create_queue(struct nvme_queue *nvmeq, int qid) > nvmeq->sq_cmds_io = dev->cmb + offset; > } > > - nvmeq->cq_vector = qid - 1; > + /* > + * A queue's vector matches the queue identifier unless the controller > + * has only one vector available. > + */ > + nvmeq->cq_vector = dev->num_vecs == 1 ? 0 : qid; > result = adapter_alloc_cq(dev, qid, nvmeq); > if (result < 0) > goto release_vector; > @@ -1909,6 +1915,10 @@ static int nvme_setup_io_queues(struct nvme_dev *dev) > int result, nr_io_queues; > unsigned long size; > > + struct irq_affinity affd = { > + .pre_vectors = 1 > + }; > + > nr_io_queues = num_present_cpus(); > result = nvme_set_queue_count(&dev->ctrl, &nr_io_queues); > if (result < 0) > @@ -1944,11 +1954,12 @@ static int nvme_setup_io_queues(struct nvme_dev *dev) > * setting up the full range we need. > */ > pci_free_irq_vectors(pdev); > - nr_io_queues = pci_alloc_irq_vectors(pdev, 1, nr_io_queues, > - PCI_IRQ_ALL_TYPES | PCI_IRQ_AFFINITY); > - if (nr_io_queues <= 0) > + result = pci_alloc_irq_vectors_affinity(pdev, 1, nr_io_queues + 1, > + PCI_IRQ_ALL_TYPES | PCI_IRQ_AFFINITY, &affd); > + if (result <= 0) > return -EIO; > - dev->max_qid = nr_io_queues; > + dev->num_vecs = result; > + dev->max_qid = max(result - 1, 1); > > /* > * Should investigate if there's a performance win from allocating > -- > 2.14.3 > Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx> -- Ming