[PATCH v3 11/15] nvme-pci: use block layer helpers to calculate num of queues

Daniel Wagner
2024-08-06T12:07:37Z

Multiqueue devices should only allocate queues for the housekeeping CPUs
when isolcpus=io_queue is set. This avoids that the isolated CPUs get
disturbed with OS workload.

Use helpers which calculates the correct number of queues which should
be used when isolcpus is used.

Signed-off-by: Daniel Wagner <dwagner@suse.de>
---
drivers/nvme/host/pci.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 5d509405a3e4..50ff2cef3d4f 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -81,7 +81,7 @@ static int io_queue_count_set(const char *val, const struct kernel_param *kp)
int ret;

ret = kstrtouint(val, 10, &n);
- if (ret != 0 || n > num_possible_cpus())
+ if (ret != 0 || n > blk_mq_num_possible_queues(0))
return -EINVAL;
return param_set_uint(val, kp);
}
@@ -2300,7 +2300,8 @@ static unsigned int nvme_max_io_queues(struct nvme_dev *dev)
*/
if (dev->ctrl.quirks & NVME_QUIRK_SHARED_TAGS)
return 1;
- return num_possible_cpus() + dev->nr_write_queues + dev->nr_poll_queues;
+ return blk_mq_num_possible_queues(0) + dev->nr_write_queues +
+ dev->nr_poll_queues;
}

static int nvme_setup_io_queues(struct nvme_dev *dev)

--
2.46.0