From 5aa54bd28ce2b066d82cdd515269b9d562bd6e66 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?H=C3=A5kon=20Bugge?= Date: Wed, 31 Mar 2021 20:43:14 +0200 Subject: rds: ib: Remove two ib_modify_qp() calls MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit For some HCAs, ib_modify_qp() is an expensive operation running virtualized. For both the active and passive side, the QP returned by the CM has the state set to RTS, so no need for this excess RTS -> RTS transition. With IB Core's ability to set the RNR Retry timer, we use this interface to shave off another ib_modify_qp(). Fixes: ec16227e1414 ("RDS/IB: Infiniband transport") Link: https://lore.kernel.org/r/1617216194-12890-3-git-send-email-haakon.bugge@oracle.com Signed-off-by: Håkon Bugge Signed-off-by: Jason Gunthorpe --- net/rds/ib_cm.c | 35 +---------------------------------- net/rds/rdma_transport.c | 1 + 2 files changed, 2 insertions(+), 34 deletions(-) (limited to 'net/rds') diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c index f5cbe963cd8f..26b069e1999d 100644 --- a/net/rds/ib_cm.c +++ b/net/rds/ib_cm.c @@ -67,31 +67,6 @@ static void rds_ib_set_flow_control(struct rds_connection *conn, u32 credits) } } -/* - * Tune RNR behavior. Without flow control, we use a rather - * low timeout, but not the absolute minimum - this should - * be tunable. - * - * We already set the RNR retry count to 7 (which is the - * smallest infinite number :-) above. - * If flow control is off, we want to change this back to 0 - * so that we learn quickly when our credit accounting is - * buggy. - * - * Caller passes in a qp_attr pointer - don't waste stack spacv - * by allocation this twice. - */ -static void -rds_ib_tune_rnr(struct rds_ib_connection *ic, struct ib_qp_attr *attr) -{ - int ret; - - attr->min_rnr_timer = IB_RNR_TIMER_000_32; - ret = ib_modify_qp(ic->i_cm_id->qp, attr, IB_QP_MIN_RNR_TIMER); - if (ret) - printk(KERN_NOTICE "ib_modify_qp(IB_QP_MIN_RNR_TIMER): err=%d\n", -ret); -} - /* * Connection established. * We get here for both outgoing and incoming connection. @@ -100,7 +75,6 @@ void rds_ib_cm_connect_complete(struct rds_connection *conn, struct rdma_cm_even { struct rds_ib_connection *ic = conn->c_transport_data; const union rds_ib_conn_priv *dp = NULL; - struct ib_qp_attr qp_attr; __be64 ack_seq = 0; __be32 credit = 0; u8 major = 0; @@ -168,14 +142,6 @@ void rds_ib_cm_connect_complete(struct rds_connection *conn, struct rdma_cm_even * the posted credit count. */ rds_ib_recv_refill(conn, 1, GFP_KERNEL); - /* Tune RNR behavior */ - rds_ib_tune_rnr(ic, &qp_attr); - - qp_attr.qp_state = IB_QPS_RTS; - err = ib_modify_qp(ic->i_cm_id->qp, &qp_attr, IB_QP_STATE); - if (err) - printk(KERN_NOTICE "ib_modify_qp(IB_QP_STATE, RTS): err=%d\n", err); - /* update ib_device with this local ipaddr */ err = rds_ib_update_ipaddr(ic->rds_ibdev, &conn->c_laddr); if (err) @@ -947,6 +913,7 @@ int rds_ib_cm_handle_connect(struct rdma_cm_id *cm_id, event->param.conn.responder_resources, event->param.conn.initiator_depth, isv6); + rdma_set_min_rnr_timer(cm_id, IB_RNR_TIMER_000_32); /* rdma_accept() calls rdma_reject() internally if it fails */ if (rdma_accept(cm_id, &conn_param)) rds_ib_conn_error(conn, "rdma_accept failed\n"); diff --git a/net/rds/rdma_transport.c b/net/rds/rdma_transport.c index 5f741e51b4ba..a9e4ff948a7d 100644 --- a/net/rds/rdma_transport.c +++ b/net/rds/rdma_transport.c @@ -87,6 +87,7 @@ static int rds_rdma_cm_event_handler_cmn(struct rdma_cm_id *cm_id, case RDMA_CM_EVENT_ADDR_RESOLVED: rdma_set_service_type(cm_id, conn->c_tos); + rdma_set_min_rnr_timer(cm_id, IB_RNR_TIMER_000_32); /* XXX do we need to clean up if this fails? */ ret = rdma_resolve_route(cm_id, RDS_RDMA_RESOLVE_TIMEOUT_MS); -- cgit v1.2.3