Allow up to 2 pages of inline for NVMF WRITE operations. This reduces
latency for 8K WRITEs by removing the need to issue a READ WR for IB,
or a REG_MR+READ WR chain for iWarp.
Signed-off-by: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/nvme/host/rdma.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index 1eb4438..9b8af98 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -40,7 +40,7 @@
#define NVME_RDMA_MAX_SEGMENTS 256
-#define NVME_RDMA_MAX_INLINE_SEGMENTS 1
+#define NVME_RDMA_MAX_INLINE_SEGMENTS 2
struct nvme_rdma_device {
struct ib_device *dev;
@@ -1086,19 +1086,28 @@ 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, int count,
+ struct nvme_command *c)
{
struct nvme_sgl_desc *sg = &c->common.dptr.sgl;
+ u32 len;
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;
+ len = req->sge[1].length;
+ if (count == 2) {
+ req->sge[2].addr = sg_dma_address(req->sg_table.sgl+1);
+ req->sge[2].length = sg_dma_len(req->sg_table.sgl+1);
+ req->sge[2].lkey = queue->device->pd->local_dma_lkey;
+ len += req->sge[2].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;
}
@@ -1191,13 +1200,13 @@ static int nvme_rdma_map_data(struct nvme_rdma_queue *queue,
return -EIO;
}
- if (count == 1) {
+ if (count <= 2) {
if (rq_data_dir(rq) == WRITE && nvme_rdma_queue_idx(queue) &&
blk_rq_payload_bytes(rq) <=
nvme_rdma_inline_data_size(queue))
return nvme_rdma_map_sg_inline(queue, req, c);
- if (dev->pd->flags & IB_PD_UNSAFE_GLOBAL_RKEY)
+ if (count == 1 && dev->pd->flags & IB_PD_UNSAFE_GLOBAL_RKEY)
return nvme_rdma_map_sg_single(queue, req, c);
}
--
1.8.3.1
--
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