From 22b5560195bd66bc43359b71821dc78cc9de56c6 Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Thu, 12 Apr 2018 09:16:10 -0600 Subject: [PATCH] nvme-pci: Separate IO and admin queue IRQ vectors 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 Cc: Ming Lei Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Reviewed-by: Ming Lei Signed-off-by: Jens Axboe --- 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 0b3b4d9fd423..fbc71fac6f1e 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 ? 1 /* admin queue */ : 0); } /** @@ -1456,7 +1458,11 @@ 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; @@ -1910,6 +1916,10 @@ 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_possible_cpus(); result = nvme_set_queue_count(&dev->ctrl, &nr_io_queues); if (result < 0) @@ -1945,11 +1955,12 @@ 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 -- 2.30.2