UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

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>
This commit is contained in:
Vu Pham 2013-11-11 19:04:29 +02:00 committed by Nicholas Bellinger
parent 4863e52565
commit f01b9f7339
1 changed files with 19 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
drivers/infiniband/ulp/isert/ib_isert.c
View File

@ -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;
/* 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;
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;