[PATCH 1/1] IB/isert: allocate RW ctxs according to max IO size

[PATCH 1/1] IB/isert: allocate RW ctxs according to max IO size

[Max Gurtovoy]

Current iSER target code allocates MR pool budget based on queue size.
Since there is no handshake between iSER initiator and target on max IO
size, we'll set the iSER target to support upto 16MiB IO operations and
allocate the correct number of RDMA ctxs according to the factor of MR's
per IO operation. This would guaranty sufficient size of the MR pool for
the required IO queue depth and IO size.

Reported-by: Krishnamraju Eraparaju <krishna2@chelsio.com>
Tested-by: Krishnamraju Eraparaju <krishna2@chelsio.com>
Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
---
 drivers/infiniband/ulp/isert/ib_isert.c | 6 ++++--
 drivers/infiniband/ulp/isert/ib_isert.h | 3 ++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index b7df38e..49f5f05 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -119,7 +119,7 @@
 {
 	struct isert_device *device = isert_conn->device;
 	struct ib_qp_init_attr attr;
-	int ret;
+	int ret, factor;
 
 	memset(&attr, 0, sizeof(struct ib_qp_init_attr));
 	attr.event_handler = isert_qp_event_callback;
@@ -128,7 +128,9 @@
 	attr.recv_cq = comp->cq;
 	attr.cap.max_send_wr = ISERT_QP_MAX_REQ_DTOS + 1;
 	attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS + 1;
-	attr.cap.max_rdma_ctxs = ISCSI_DEF_XMIT_CMDS_MAX;
+	factor = rdma_rw_mr_factor(device->ib_device, cma_id->port_num,
+				   ISCSI_ISER_MAX_SG_TABLESIZE);
+	attr.cap.max_rdma_ctxs = ISCSI_DEF_XMIT_CMDS_MAX * factor;
 	attr.cap.max_send_sge = device->ib_device->attrs.max_send_sge;
 	attr.cap.max_recv_sge = 1;
 	attr.sq_sig_type = IB_SIGNAL_REQ_WR;
diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h
index 3b296ba..c9ccf1d 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.h
+++ b/drivers/infiniband/ulp/isert/ib_isert.h
@@ -63,7 +63,8 @@
 		(ISER_RX_PAYLOAD_SIZE + sizeof(u64) + sizeof(struct ib_sge) + \
 		 sizeof(struct ib_cqe) + sizeof(bool)))
 
-#define ISCSI_ISER_SG_TABLESIZE		256
+/* Maximum support is 16MB I/O size */
+#define ISCSI_ISER_MAX_SG_TABLESIZE	4096
 
 enum isert_desc_type {
 	ISCSI_TX_CONTROL,
-- 
1.8.3.1

Re: [PATCH 1/1] IB/isert: allocate RW ctxs according to max IO size

[Sagi Grimberg]

Looks good to me Max, thanks

Acked-by: Sagi Grimberg <sagi@grimberg.me>

Re: [PATCH 1/1] IB/isert: allocate RW ctxs according to max IO size

[Jason Gunthorpe]

On Wed, Jul 08, 2020 at 12:19:08PM +0300, Max Gurtovoy wrote:
> Current iSER target code allocates MR pool budget based on queue size.
> Since there is no handshake between iSER initiator and target on max IO
> size, we'll set the iSER target to support upto 16MiB IO operations and
> allocate the correct number of RDMA ctxs according to the factor of MR's
> per IO operation. This would guaranty sufficient size of the MR pool for
> the required IO queue depth and IO size.
> 
> Reported-by: Krishnamraju Eraparaju <krishna2@chelsio.com>
> Tested-by: Krishnamraju Eraparaju <krishna2@chelsio.com>
> Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
> Acked-by: Sagi Grimberg <sagi@grimberg.me>
> ---
>  drivers/infiniband/ulp/isert/ib_isert.c | 6 ++++--
>  drivers/infiniband/ulp/isert/ib_isert.h | 3 ++-
>  2 files changed, 6 insertions(+), 3 deletions(-)

Applied to for-next, thanks

Jason