diff options
| author | Vu Pham <vu@mellanox.com> | 2013-11-11 19:04:29 +0200 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2013-11-12 13:07:52 -0800 |
| commit | f01b9f73392b48c6cda7c2c66594c73137c776da (patch) | |
| tree | e673d3361ccb1a79de47609dc36d9760411084c9 | |
| parent | 4863e525659abbc903aacc67fd916f12914f6c1d (diff) | |
iser-target: Avoid using FRMR for single dma entry requests
This patch changes isert_reg_rdma_frwr() to not use FRMR for single
dma entry requests from small I/Os, in order to avoid the associated
memory registration overhead.
Using DMA MR is sufficient here for the single dma entry requests,
and addresses a >= v3.12 performance regression.
Signed-off-by: Vu Pham <vu@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.12+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
| -rw-r--r-- | drivers/infiniband/ulp/isert/ib_isert.c | 32 |
1 files changed, 20 insertions, 12 deletions
diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c index 27708c3430d..bbd86e82e04 100644 --- a/drivers/infiniband/ulp/isert/ib_isert.c +++ b/drivers/infiniband/ulp/isert/ib_isert.c @@ -2297,18 +2297,26 @@ isert_reg_rdma_frwr(struct iscsi_conn *conn, struct iscsi_cmd *cmd, data_len = min(data_left, rdma_write_max); wr->cur_rdma_length = data_len; - spin_lock_irqsave(&isert_conn->conn_lock, flags); - fr_desc = list_first_entry(&isert_conn->conn_frwr_pool, - struct fast_reg_descriptor, list); - list_del(&fr_desc->list); - spin_unlock_irqrestore(&isert_conn->conn_lock, flags); - wr->fr_desc = fr_desc; - - ret = isert_fast_reg_mr(fr_desc, isert_cmd, isert_conn, - ib_sge, offset, data_len); - if (ret) { - list_add_tail(&fr_desc->list, &isert_conn->conn_frwr_pool); - goto unmap_sg; + /* if there is a single dma entry, dma mr is sufficient */ + if (count == 1) { + ib_sge->addr = ib_sg_dma_address(ib_dev, &sg_start[0]); + ib_sge->length = ib_sg_dma_len(ib_dev, &sg_start[0]); + ib_sge->lkey = isert_conn->conn_mr->lkey; + wr->fr_desc = NULL; + } else { + spin_lock_irqsave(&isert_conn->conn_lock, flags); + fr_desc = list_first_entry(&isert_conn->conn_frwr_pool, + struct fast_reg_descriptor, list); + list_del(&fr_desc->list); + spin_unlock_irqrestore(&isert_conn->conn_lock, flags); + wr->fr_desc = fr_desc; + + ret = isert_fast_reg_mr(fr_desc, isert_cmd, isert_conn, + ib_sge, offset, data_len); + if (ret) { + list_add_tail(&fr_desc->list, &isert_conn->conn_frwr_pool); + goto unmap_sg; + } } return 0; |