[PATCHv2 2/4] nvme-pci: Distribute io queue types after creation

Ming Lei
2019-01-04T02:31:22Z

On Thu, Jan 03, 2019@03:50:31PM -0700, Keith Busch wrote:
> The dev->io_queues types were set based on the results of the nvme set
> feature "number of queues" and the IRQ allocation. This result does not
> mean we're going to successfully allocate and create those IO queues,
> though. A failure there will cause blk-mq to have NULL hctx's because the
> map's nr_hw_queues accounts for more queues than were actually created.
>
> Adjust the io_queue types after we've created them when we have less than
> originally desired.
>
> Fixes: 3b6592f70ad7b ("nvme: utilize two queue maps, one for reads and one for writes")
> Signed-off-by: Keith Busch <keith.busch at intel.com>
> ---
> drivers/nvme/host/pci.c | 46 ++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 40 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 98332d0a80f0..1481bb6d9c42 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -1733,6 +1733,30 @@ static int nvme_pci_configure_admin_queue(struct nvme_dev *dev)
> return result;
> }
>
> +static void nvme_distribute_queues(struct nvme_dev *dev, unsigned int io_queues)
> +{
> + unsigned int irq_queues, this_p_queues = dev->io_queues[HCTX_TYPE_POLL],
> + this_w_queues = dev->io_queues[HCTX_TYPE_DEFAULT];
> +
> + if (!io_queues) {
> + dev->io_queues[HCTX_TYPE_POLL] = 0;
> + dev->io_queues[HCTX_TYPE_DEFAULT] = 0;
> + dev->io_queues[HCTX_TYPE_READ] = 0;
> + return;
> + }
> +
> + if (this_p_queues >= io_queues)
> + this_p_queues = io_queues - 1;
> + irq_queues = io_queues - this_p_queues;
> +
> + if (this_w_queues > irq_queues)
> + this_w_queues = irq_queues;
> +
> + dev->io_queues[HCTX_TYPE_POLL] = this_p_queues;
> + dev->io_queues[HCTX_TYPE_DEFAULT] = this_w_queues;
> + dev->io_queues[HCTX_TYPE_READ] = irq_queues - this_w_queues;
> +}
> +
> static int nvme_create_io_queues(struct nvme_dev *dev)
> {
> unsigned i, max, rw_queues;
> @@ -1761,6 +1785,13 @@ static int nvme_create_io_queues(struct nvme_dev *dev)
> break;
> }
>
> + /*
> + * If we've created less than expected io queues, redistribute the
> + * dev->io_queues[] types accordingly.
> + */
> + if (dev->online_queues - 1 != dev->max_qid)
> + nvme_distribute_queues(dev, dev->online_queues - 1);
> +
> /*
> * Ignore failing Create SQ/CQ commands, we can continue with less
> * than the desired amount of queues, and even a controller without
> @@ -2185,11 +2216,6 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
> result = max(result - 1, 1);
> dev->max_qid = result + dev->io_queues[HCTX_TYPE_POLL];
>
> - dev_info(dev->ctrl.device, "%d/%d/%d default/read/poll queues\n",
> - dev->io_queues[HCTX_TYPE_DEFAULT],
> - dev->io_queues[HCTX_TYPE_READ],
> - dev->io_queues[HCTX_TYPE_POLL]);
> -
> /*
> * Should investigate if there's a performance win from allocating
> * more queues than interrupt vectors; it might allow the submission
> @@ -2203,7 +2229,15 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
> return result;
> }
> set_bit(NVMEQ_ENABLED, &adminq->flags);
> - return nvme_create_io_queues(dev);
> + result = nvme_create_io_queues(dev);
> +
> + if (!result)
> + dev_info(dev->ctrl.device, "%d/%d/%d default/read/poll queues\n",
> + dev->io_queues[HCTX_TYPE_DEFAULT],
> + dev->io_queues[HCTX_TYPE_READ],
> + dev->io_queues[HCTX_TYPE_POLL]);
> + return result;
> +
> }
>
> static void nvme_del_queue_end(struct request *req, blk_status_t error)
> --
> 2.14.4
>

This way should be better given it covers irq allocation failure and
queue creating/initialization failure.

Reviewed-by: Ming Lei <ming.lei at redhat.com>

Thanks,
Ming