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Commit 22b55601 authored by Keith Busch's avatar Keith Busch Committed by Jens Axboe
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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 <jianchao.w.wang@oracle.com>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: default avatarKeith Busch <keith.busch@intel.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a6ff7262

drivers/nvme/host/pci.c

+17 −6
Original line number Diff line number Diff line
@@ -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