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nvmet: pci-epf: Keep completion queues mapped

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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: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
This commit is contained in:
Damien Le Moal
2025-03-13 17:22:18 +09:00
committed by Keith Busch
parent e3e68311ea
commit ea7789c154
1 changed files with 25 additions and 38 deletions
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63
drivers/nvme/target/pci-epf.c
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@@ -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);