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| author | Matthew Wilcox <matthew.r.wilcox@intel.com> | 2013-06-20 16:53:48 +0200 |
|---|---|---|
| committer | Matthew Wilcox <matthew.r.wilcox@intel.com> | 2013-06-20 17:09:23 +0200 |
| commit | 063a8096f3dbca7521d5918b3aea7ab46c5d2fe9 (patch) | |
| tree | 24007515e6df6c7b78a100508884a5889a8ff789 /drivers/block | |
| parent | NVMe: Use kzalloc instead of kmalloc+memset (diff) | |
| download | linux-063a8096f3dbca7521d5918b3aea7ab46c5d2fe9.tar.xz linux-063a8096f3dbca7521d5918b3aea7ab46c5d2fe9.zip | |
NVMe: Restructure MSI / MSI-X setup
The current code copies 'nr_io_queues' into 'q_count', modifies
'nr_io_queues' during MSI-X setup, then resets 'nr_io_queues' for
MSI setup. Instead, copy 'nr_io_queues' into 'vecs' and modify 'vecs'
during both MSI-X and MSI setup.
This lets us simplify the for-loops that set up MSI-X and MSI, and opens
the possibility of using more I/O queues than we have interrupt vectors,
should future benchmarking prove that to be a useful feature.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/nvme-core.c | 44 |
1 files changed, 23 insertions, 21 deletions
diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c index ce79a590b45b..de3a75978c56 100644 --- a/drivers/block/nvme-core.c +++ b/drivers/block/nvme-core.c @@ -1638,7 +1638,7 @@ static int set_queue_count(struct nvme_dev *dev, int count) static int nvme_setup_io_queues(struct nvme_dev *dev) { struct pci_dev *pdev = dev->pci_dev; - int result, cpu, i, nr_io_queues, db_bar_size, q_depth, q_count; + int result, cpu, i, vecs, nr_io_queues, db_bar_size, q_depth; nr_io_queues = num_online_cpus(); result = set_queue_count(dev, nr_io_queues); @@ -1647,7 +1647,6 @@ static int nvme_setup_io_queues(struct nvme_dev *dev) if (result < nr_io_queues) nr_io_queues = result; - q_count = nr_io_queues; /* Deregister the admin queue's interrupt */ free_irq(dev->entry[0].vector, dev->queues[0]); @@ -1659,39 +1658,42 @@ static int nvme_setup_io_queues(struct nvme_dev *dev) dev->queues[0]->q_db = dev->dbs; } - for (i = 0; i < nr_io_queues; i++) + vecs = nr_io_queues; + for (i = 0; i < vecs; i++) dev->entry[i].entry = i; for (;;) { - result = pci_enable_msix(pdev, dev->entry, nr_io_queues); - if (result == 0) { + result = pci_enable_msix(pdev, dev->entry, vecs); + if (result <= 0) break; - } else if (result > 0) { - nr_io_queues = result; - continue; - } else { - nr_io_queues = 0; - break; - } + vecs = result; } - if (nr_io_queues == 0) { - nr_io_queues = q_count; + if (result < 0) { + vecs = nr_io_queues; + if (vecs > 32) + vecs = 32; for (;;) { - result = pci_enable_msi_block(pdev, nr_io_queues); + result = pci_enable_msi_block(pdev, vecs); if (result == 0) { - for (i = 0; i < nr_io_queues; i++) + for (i = 0; i < vecs; i++) dev->entry[i].vector = i + pdev->irq; break; - } else if (result > 0) { - nr_io_queues = result; - continue; - } else { - nr_io_queues = 1; + } else if (result < 0) { + vecs = 1; break; } + vecs = result; } } + /* + * Should investigate if there's a performance win from allocating + * more queues than interrupt vectors; it might allow the submission + * path to scale better, even if the receive path is limited by the + * number of interrupts. + */ + nr_io_queues = vecs; + result = queue_request_irq(dev, dev->queues[0], "nvme admin"); /* XXX: handle failure here */ |