From e5ce53799932c240b1c5ddcdd95b7fb8fcf0917a Mon Sep 17 00:00:00 2001 From: Jim Harris Date: Wed, 8 Apr 2015 21:46:18 +0000 Subject: [PATCH] nvme: fall back to a smaller MSI-X vector allocation if necessary Previously, if per-CPU MSI-X vectors could not be allocated, nvme(4) would fall back to INTx with a single I/O queue pair. This change will still fall back to a single I/O queue pair, but allocate MSI-X vectors instead of reverting to INTx. MFC after: 1 week Sponsored by: Intel --- sys/dev/nvme/nvme_ctrlr.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/sys/dev/nvme/nvme_ctrlr.c b/sys/dev/nvme/nvme_ctrlr.c index cf3b3b21583..6b0d6f3451f 100644 --- a/sys/dev/nvme/nvme_ctrlr.c +++ b/sys/dev/nvme/nvme_ctrlr.c @@ -1144,9 +1144,17 @@ nvme_ctrlr_construct(struct nvme_controller *ctrlr, device_t dev) /* One vector per IO queue, plus one vector for admin queue. */ num_vectors = ctrlr->num_io_queues + 1; - if (pci_msix_count(dev) < num_vectors) { + /* + * If we cannot even allocate 2 vectors (one for admin, one for + * I/O), then revert to INTx. + */ + if (pci_msix_count(dev) < 2) { ctrlr->msix_enabled = 0; goto intx; + } else if (pci_msix_count(dev) < num_vectors) { + ctrlr->per_cpu_io_queues = FALSE; + ctrlr->num_io_queues = 1; + num_vectors = 2; /* one for admin, one for I/O */ } if (pci_alloc_msix(dev, &num_vectors) != 0) {