[PATCH] NVMe: IRQ vector sharing depends on resources
Jon Derrick
jonathan.derrick at intel.com
Tue May 19 19:20:16 PDT 2015
If the number of io queues + admin queue is less than or equal
to the number of vectors, no IRQs will be shared. If there are more
io queues + admin queue than there are vectors, qid 0 (admin queue)
and qid 1 will share a vector
Signed-off-by: Jon Derrick <jonathan.derrick at intel.com>
---
May improve IRQ coalescing capabilities
drivers/block/nvme-core.c | 17 ++++++++++++-----
include/linux/nvme.h | 1 +
2 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index e23be20..a2e06eb 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -1457,7 +1457,8 @@ static int nvme_create_queue(struct nvme_queue *nvmeq, int qid)
struct nvme_dev *dev = nvmeq->dev;
int result;
- nvmeq->cq_vector = qid - 1;
+ nvmeq->cq_vector = qid - dev->shared_vec;
+
result = adapter_alloc_cq(dev, qid, nvmeq);
if (result < 0)
return result;
@@ -2265,11 +2266,12 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
if (!pdev->irq)
pci_disable_msix(pdev);
- for (i = 0; i < nr_io_queues; i++)
+ for (i = 0; i <= nr_io_queues; i++)
dev->entry[i].entry = i;
- vecs = pci_enable_msix_range(pdev, dev->entry, 1, nr_io_queues);
+ vecs = pci_enable_msix_range(pdev, dev->entry, 1, nr_io_queues + 1);
+
if (vecs < 0) {
- vecs = pci_enable_msi_range(pdev, 1, min(nr_io_queues, 32));
+ vecs = pci_enable_msi_range(pdev, 1, min(nr_io_queues + 1, 32));
if (vecs < 0) {
vecs = 1;
} else {
@@ -2278,6 +2280,9 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
}
}
+ if (vecs < nr_io_queues + 1)
+ dev->shared_vec = 1;
+
/*
* Should investigate if there's a performance win from allocating
* more queues than interrupt vectors; it might allow the submission
@@ -2285,6 +2290,8 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
* number of interrupts.
*/
nr_io_queues = vecs;
+ if (!dev->shared_vec)
+ --nr_io_queues;
dev->max_qid = nr_io_queues;
result = queue_request_irq(dev, adminq, adminq->irqname);
@@ -2971,7 +2978,7 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
dev = kzalloc_node(sizeof(*dev), GFP_KERNEL, node);
if (!dev)
return -ENOMEM;
- dev->entry = kzalloc_node(num_possible_cpus() * sizeof(*dev->entry),
+ dev->entry = kzalloc_node((num_possible_cpus() + 1) * sizeof(*dev->entry),
GFP_KERNEL, node);
if (!dev->entry)
goto free;
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 0adad4a..e5386e1 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -85,6 +85,7 @@ struct nvme_dev {
u32 db_stride;
u32 ctrl_config;
struct msix_entry *entry;
+ int shared_vec;
struct nvme_bar __iomem *bar;
struct list_head namespaces;
struct kref kref;
--
2.1.4
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