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nvme-rdma: support up to 4 segments of inline data

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Allow up to 4 segments of inline data for NVMF WRITE operations. This
reduces latency for small WRITEs by removing the need for the target to
issue a READ WR for IB, or a REG_MR + READ WR chain for iWarp.

Also cap the inline segments used based on the limitations of the
device.

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Steve Wise 2018-06-20 07:15:05 -07:00 committed by Christoph Hellwig
parent 55eb942eda
commit 64a741c1ea
1 changed files with 27 additions and 11 deletions
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38
drivers/nvme/host/rdma.c
View file

@ -40,13 +40,14 @@
#define NVME_RDMA_MAX_SEGMENTS 256
#define NVME_RDMA_MAX_INLINE_SEGMENTS 1
#define NVME_RDMA_MAX_INLINE_SEGMENTS 4
struct nvme_rdma_device {
struct ib_device *dev;
struct ib_pd *pd;
struct kref ref;
struct list_head entry;
unsigned int num_inline_segments;
};
struct nvme_rdma_qe {
@ -117,6 +118,7 @@ struct nvme_rdma_ctrl {
struct sockaddr_storage src_addr;
struct nvme_ctrl ctrl;
bool use_inline_data;
};
static inline struct nvme_rdma_ctrl *to_rdma_ctrl(struct nvme_ctrl *ctrl)
@ -249,7 +251,7 @@ static int nvme_rdma_create_qp(struct nvme_rdma_queue *queue, const int factor)
/* +1 for drain */
init_attr.cap.max_recv_wr = queue->queue_size + 1;
init_attr.cap.max_recv_sge = 1;
init_attr.cap.max_send_sge = 1 + NVME_RDMA_MAX_INLINE_SEGMENTS;
init_attr.cap.max_send_sge = 1 + dev->num_inline_segments;
init_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
init_attr.qp_type = IB_QPT_RC;
init_attr.send_cq = queue->ib_cq;
@ -374,6 +376,8 @@ nvme_rdma_find_get_device(struct rdma_cm_id *cm_id)
goto out_free_pd;
}
ndev->num_inline_segments = min(NVME_RDMA_MAX_INLINE_SEGMENTS,
ndev->dev->attrs.max_sge - 1);
list_add(&ndev->entry, &device_list);
out_unlock:
mutex_unlock(&device_list_mutex);
@ -925,6 +929,9 @@ static void nvme_rdma_reconnect_ctrl_work(struct work_struct *work)
if (ret)
goto requeue;
if (ctrl->ctrl.sgls & (1 << 20))
ctrl->use_inline_data = true;
if (ctrl->ctrl.queue_count > 1) {
ret = nvme_rdma_configure_io_queues(ctrl, false);
if (ret)
@ -1090,19 +1097,27 @@ static int nvme_rdma_set_sg_null(struct nvme_command *c)
}
static int nvme_rdma_map_sg_inline(struct nvme_rdma_queue *queue,
struct nvme_rdma_request *req, struct nvme_command *c)
struct nvme_rdma_request *req, struct nvme_command *c,
int count)
{
struct nvme_sgl_desc *sg = &c->common.dptr.sgl;
struct scatterlist *sgl = req->sg_table.sgl;
struct ib_sge *sge = &req->sge[1];
u32 len = 0;
int i;
req->sge[1].addr = sg_dma_address(req->sg_table.sgl);
req->sge[1].length = sg_dma_len(req->sg_table.sgl);
req->sge[1].lkey = queue->device->pd->local_dma_lkey;
for (i = 0; i < count; i++, sgl++, sge++) {
sge->addr = sg_dma_address(sgl);
sge->length = sg_dma_len(sgl);
sge->lkey = queue->device->pd->local_dma_lkey;
len += sge->length;
}
sg->addr = cpu_to_le64(queue->ctrl->ctrl.icdoff);
sg->length = cpu_to_le32(sg_dma_len(req->sg_table.sgl));
sg->length = cpu_to_le32(len);
sg->type = (NVME_SGL_FMT_DATA_DESC << 4) | NVME_SGL_FMT_OFFSET;
req->num_sge++;
req->num_sge += count;
return 0;
}
@ -1195,15 +1210,16 @@ static int nvme_rdma_map_data(struct nvme_rdma_queue *queue,
goto out_free_table;
}
if (count == 1) {
if (count <= dev->num_inline_segments) {
if (rq_data_dir(rq) == WRITE && nvme_rdma_queue_idx(queue) &&
queue->ctrl->use_inline_data &&
blk_rq_payload_bytes(rq) <=
nvme_rdma_inline_data_size(queue)) {
ret = nvme_rdma_map_sg_inline(queue, req, c);
ret = nvme_rdma_map_sg_inline(queue, req, c, count);
goto out;
}
if (dev->pd->flags & IB_PD_UNSAFE_GLOBAL_RKEY) {
if (count == 1 && dev->pd->flags & IB_PD_UNSAFE_GLOBAL_RKEY) {
ret = nvme_rdma_map_sg_single(queue, req, c);
goto out;
}