Commit ea7789c1 authored by Damien Le Moal's avatar Damien Le Moal Committed by Keith Busch
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nvmet: pci-epf: Keep completion queues mapped 



Instead of mapping and unmapping the completion queues memory to the
host PCI address space whenever nvmet_pci_epf_cq_work() is called, map
a completion queue to the host PCI address space when the completion
queue is created with nvmet_pci_epf_create_cq() and unmap it when the
completion queue is deleted with nvmet_pci_epf_delete_cq().

This removes the completion queue mapping/unmapping from
nvmet_pci_epf_cq_work() and significantly increases performance. For
a single job 4K random read QD=1 workload, the IOPS is increased from
23 KIOPS to 25 KIOPS. Some significant throughput increasde for high
queue depth and large IOs workloads can also be seen.

Since the functions nvmet_pci_epf_map_queue() and
nvmet_pci_epf_unmap_queue() are called respectively only from
nvmet_pci_epf_create_cq() and nvmet_pci_epf_delete_cq(), these functions
are removed and open-coded in their respective call sites.

Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarKeith Busch <kbusch@kernel.org>
parent e3e68311

drivers/nvme/target/pci-epf.c

+25 −38
Original line number Diff line number Diff line
@@ -1264,6 +1264,7 @@ static u16 nvmet_pci_epf_create_cq(struct nvmet_ctrl *tctrl, 
	struct nvmet_pci_epf_ctrl *ctrl = tctrl->drvdata;

	struct nvmet_pci_epf_queue *cq = &ctrl->cq[cqid];

	u16 status;

	int ret;



	if (test_bit(NVMET_PCI_EPF_Q_LIVE, &cq->flags))

		return NVME_SC_QID_INVALID | NVME_STATUS_DNR;
@@ -1298,6 +1299,24 @@ static u16 nvmet_pci_epf_create_cq(struct nvmet_ctrl *tctrl, 
	if (status != NVME_SC_SUCCESS)

		goto err;



	/*

	 * Map the CQ PCI address space and since PCI endpoint controllers may

	 * return a partial mapping, check that the mapping is large enough.

	 */

	ret = nvmet_pci_epf_mem_map(ctrl->nvme_epf, cq->pci_addr, cq->pci_size,

				    &cq->pci_map);

	if (ret) {

		dev_err(ctrl->dev, "Failed to map CQ %u (err=%d)\n",

			cq->qid, ret);

		goto err_internal;

	}



	if (cq->pci_map.pci_size < cq->pci_size) {

		dev_err(ctrl->dev, "Invalid partial mapping of queue %u\n",

			cq->qid);

		goto err_unmap_queue;

	}



	set_bit(NVMET_PCI_EPF_Q_LIVE, &cq->flags);



	dev_dbg(ctrl->dev, "CQ[%u]: %u entries of %zu B, IRQ vector %u\n",
@@ -1305,6 +1324,10 @@ static u16 nvmet_pci_epf_create_cq(struct nvmet_ctrl *tctrl, 


	return NVME_SC_SUCCESS;



err_unmap_queue:

	nvmet_pci_epf_mem_unmap(ctrl->nvme_epf, &cq->pci_map);

err_internal:

	status = NVME_SC_INTERNAL | NVME_STATUS_DNR;

err:

	if (test_and_clear_bit(NVMET_PCI_EPF_Q_IRQ_ENABLED, &cq->flags))

		nvmet_pci_epf_remove_irq_vector(ctrl, cq->vector);
@@ -1322,6 +1345,7 @@ static u16 nvmet_pci_epf_delete_cq(struct nvmet_ctrl *tctrl, u16 cqid) 
	cancel_delayed_work_sync(&cq->work);

	nvmet_pci_epf_drain_queue(cq);

	nvmet_pci_epf_remove_irq_vector(ctrl, cq->vector);

	nvmet_pci_epf_mem_unmap(ctrl->nvme_epf, &cq->pci_map);



	return NVME_SC_SUCCESS;

}
@@ -1553,36 +1577,6 @@ static void nvmet_pci_epf_free_queues(struct nvmet_pci_epf_ctrl *ctrl) 
	ctrl->cq = NULL;

}



static int nvmet_pci_epf_map_queue(struct nvmet_pci_epf_ctrl *ctrl,

				   struct nvmet_pci_epf_queue *queue)

{

	struct nvmet_pci_epf *nvme_epf = ctrl->nvme_epf;

	int ret;



	ret = nvmet_pci_epf_mem_map(nvme_epf, queue->pci_addr,

				      queue->pci_size, &queue->pci_map);

	if (ret) {

		dev_err(ctrl->dev, "Failed to map queue %u (err=%d)\n",

			queue->qid, ret);

		return ret;

	}



	if (queue->pci_map.pci_size < queue->pci_size) {

		dev_err(ctrl->dev, "Invalid partial mapping of queue %u\n",

			queue->qid);

		nvmet_pci_epf_mem_unmap(nvme_epf, &queue->pci_map);

		return -ENOMEM;

	}



	return 0;

}



static inline void nvmet_pci_epf_unmap_queue(struct nvmet_pci_epf_ctrl *ctrl,

					     struct nvmet_pci_epf_queue *queue)

{

	nvmet_pci_epf_mem_unmap(ctrl->nvme_epf, &queue->pci_map);

}



static void nvmet_pci_epf_exec_iod_work(struct work_struct *work)

{

	struct nvmet_pci_epf_iod *iod =
@@ -1746,11 +1740,7 @@ static void nvmet_pci_epf_cq_work(struct work_struct *work) 
	struct nvme_completion *cqe;

	struct nvmet_pci_epf_iod *iod;

	unsigned long flags;

	int ret, n = 0;



	ret = nvmet_pci_epf_map_queue(ctrl, cq);

	if (ret)

		goto again;

	int ret = 0, n = 0;



	while (test_bit(NVMET_PCI_EPF_Q_LIVE, &cq->flags) && ctrl->link_up) {
@@ -1797,8 +1787,6 @@ static void nvmet_pci_epf_cq_work(struct work_struct *work) 
		n++;

	}



	nvmet_pci_epf_unmap_queue(ctrl, cq);



	/*

	 * We do not support precise IRQ coalescing time (100ns units as per

	 * NVMe specifications). So if we have posted completion entries without
@@ -1807,7 +1795,6 @@ static void nvmet_pci_epf_cq_work(struct work_struct *work) 
	if (n)

		nvmet_pci_epf_raise_irq(ctrl, cq, true);



again:

	if (ret < 0)

		queue_delayed_work(system_highpri_wq, &cq->work,

				   NVMET_PCI_EPF_CQ_RETRY_INTERVAL);