[net-next][PATCH v2 12/13] RDS: IB: allocate extra space on queues for FRMR support

From: Santosh Shilimkar
Date: Sat Feb 27 2016 - 21:20:34 EST


Fastreg MR(FRMR) memory registration and invalidation makes use
of work request and completion queues for its operation. Patch
allocates extra queue space towards these operation(s).

Signed-off-by: Santosh Shilimkar <ssantosh@xxxxxxxxxx>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxxxxxx>
---
net/rds/ib.h | 4 ++++
net/rds/ib_cm.c | 16 ++++++++++++----
2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/net/rds/ib.h b/net/rds/ib.h
index c5eddc2..eeb0d6c 100644
--- a/net/rds/ib.h
+++ b/net/rds/ib.h
@@ -14,6 +14,7 @@

#define RDS_IB_DEFAULT_RECV_WR 1024
#define RDS_IB_DEFAULT_SEND_WR 256
+#define RDS_IB_DEFAULT_FR_WR 512

#define RDS_IB_DEFAULT_RETRY_COUNT 2

@@ -122,6 +123,9 @@ struct rds_ib_connection {
struct ib_wc i_send_wc[RDS_IB_WC_MAX];
struct ib_wc i_recv_wc[RDS_IB_WC_MAX];

+ /* To control the number of wrs from fastreg */
+ atomic_t i_fastreg_wrs;
+
/* interrupt handling */
struct tasklet_struct i_send_tasklet;
struct tasklet_struct i_recv_tasklet;
diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c
index 7f68abc..83f4673 100644
--- a/net/rds/ib_cm.c
+++ b/net/rds/ib_cm.c
@@ -363,7 +363,7 @@ static int rds_ib_setup_qp(struct rds_connection *conn)
struct ib_qp_init_attr attr;
struct ib_cq_init_attr cq_attr = {};
struct rds_ib_device *rds_ibdev;
- int ret;
+ int ret, fr_queue_space;

/*
* It's normal to see a null device if an incoming connection races
@@ -373,6 +373,12 @@ static int rds_ib_setup_qp(struct rds_connection *conn)
if (!rds_ibdev)
return -EOPNOTSUPP;

+ /* The fr_queue_space is currently set to 512, to add extra space on
+ * completion queue and send queue. This extra space is used for FRMR
+ * registration and invalidation work requests
+ */
+ fr_queue_space = (rds_ibdev->use_fastreg ? RDS_IB_DEFAULT_FR_WR : 0);
+
/* add the conn now so that connection establishment has the dev */
rds_ib_add_conn(rds_ibdev, conn);

@@ -384,7 +390,7 @@ static int rds_ib_setup_qp(struct rds_connection *conn)
/* Protection domain and memory range */
ic->i_pd = rds_ibdev->pd;

- cq_attr.cqe = ic->i_send_ring.w_nr + 1;
+ cq_attr.cqe = ic->i_send_ring.w_nr + fr_queue_space + 1;

ic->i_send_cq = ib_create_cq(dev, rds_ib_cq_comp_handler_send,
rds_ib_cq_event_handler, conn,
@@ -424,7 +430,7 @@ static int rds_ib_setup_qp(struct rds_connection *conn)
attr.event_handler = rds_ib_qp_event_handler;
attr.qp_context = conn;
/* + 1 to allow for the single ack message */
- attr.cap.max_send_wr = ic->i_send_ring.w_nr + 1;
+ attr.cap.max_send_wr = ic->i_send_ring.w_nr + fr_queue_space + 1;
attr.cap.max_recv_wr = ic->i_recv_ring.w_nr + 1;
attr.cap.max_send_sge = rds_ibdev->max_sge;
attr.cap.max_recv_sge = RDS_IB_RECV_SGE;
@@ -432,6 +438,7 @@ static int rds_ib_setup_qp(struct rds_connection *conn)
attr.qp_type = IB_QPT_RC;
attr.send_cq = ic->i_send_cq;
attr.recv_cq = ic->i_recv_cq;
+ atomic_set(&ic->i_fastreg_wrs, RDS_IB_DEFAULT_FR_WR);

/*
* XXX this can fail if max_*_wr is too large? Are we supposed
@@ -751,7 +758,8 @@ void rds_ib_conn_shutdown(struct rds_connection *conn)
*/
wait_event(rds_ib_ring_empty_wait,
rds_ib_ring_empty(&ic->i_recv_ring) &&
- (atomic_read(&ic->i_signaled_sends) == 0));
+ (atomic_read(&ic->i_signaled_sends) == 0) &&
+ (atomic_read(&ic->i_fastreg_wrs) == RDS_IB_DEFAULT_FR_WR));
tasklet_kill(&ic->i_send_tasklet);
tasklet_kill(&ic->i_recv_tasklet);

--
1.9.1