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authorVu Pham <vu@mellanox.com>2013-11-11 19:04:29 +0200
committerNicholas Bellinger <nab@linux-iscsi.org>2013-11-12 13:07:52 -0800
commitf01b9f73392b48c6cda7c2c66594c73137c776da (patch)
treee673d3361ccb1a79de47609dc36d9760411084c9 /drivers/infiniband
parent4863e525659abbc903aacc67fd916f12914f6c1d (diff)
downloadop-kernel-dev-f01b9f73392b48c6cda7c2c66594c73137c776da.zip
op-kernel-dev-f01b9f73392b48c6cda7c2c66594c73137c776da.tar.gz
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>
Diffstat (limited to 'drivers/infiniband')
-rw-r--r--drivers/infiniband/ulp/isert/ib_isert.c32
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 27708c3..bbd86e8 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;
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