From: Chuck Lever <chuck.lever@xxxxxxxxxx>
For upper layer protocols that request rw_ctxs, ib_create_qp()
adjusts ib_qp_init_attr::max_send_wr to accommodate the WQEs those
rw_ctxs will consume. See rdma_rw_init_qp() for details.
To actually use those additional WQEs, svc_rdma_accept() needs to
retrieve the corrected SQ depth after calling rdma_create_qp() and
set newxprt->sc_sq_depth and newxprt->sc_sq_avail so that
svc_rdma_send() and svc_rdma_post_chunk_ctxt() can utilize those
WQEs.
The NVMe target driver, for example, already does this properly.
Fixes: 26fb2254dd33 ("svcrdma: Estimate Send Queue depth properly")
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
net/sunrpc/xprtrdma/svc_rdma_transport.c | 39 +++++++++++++++++++-----------
1 file changed, 25 insertions(+), 14 deletions(-)
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 0541aa54674c..790841864153 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -369,12 +369,12 @@ static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
*/
static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
{
+ unsigned int ctxts, rq_depth, sq_depth;
struct svcxprt_rdma *listen_rdma;
struct svcxprt_rdma *newxprt = NULL;
struct rdma_conn_param conn_param;
struct rpcrdma_connect_private pmsg;
struct ib_qp_init_attr qp_attr;
- unsigned int ctxts, rq_depth;
struct ib_device *dev;
int ret = 0;
RPC_IFDEBUG(struct sockaddr *sap);
@@ -421,24 +421,32 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
newxprt->sc_max_requests = rq_depth - 2;
newxprt->sc_max_bc_requests = 2;
}
+
ctxts = rdma_rw_mr_factor(dev, newxprt->sc_port_num, RPCSVC_MAXPAGES);
ctxts *= newxprt->sc_max_requests;
- newxprt->sc_sq_depth = rq_depth + ctxts;
- if (newxprt->sc_sq_depth > dev->attrs.max_qp_wr)
- newxprt->sc_sq_depth = dev->attrs.max_qp_wr;
- atomic_set(&newxprt->sc_sq_avail, newxprt->sc_sq_depth);
+
+ sq_depth = newxprt->sc_max_requests + newxprt->sc_max_bc_requests + 1;
+ if (sq_depth > dev->attrs.max_qp_wr)
+ sq_depth = dev->attrs.max_qp_wr;
newxprt->sc_pd = ib_alloc_pd(dev, 0);
if (IS_ERR(newxprt->sc_pd)) {
trace_svcrdma_pd_err(newxprt, PTR_ERR(newxprt->sc_pd));
goto errout;
}
- newxprt->sc_sq_cq = ib_alloc_cq_any(dev, newxprt, newxprt->sc_sq_depth,
+
+ /* The Completion Queue depth is the maximum number of signaled
+ * WRs expected to be in flight. Every Send WR is signaled, and
+ * each rw_ctx has a chain of WRs, but only one WR in each chain
+ * is signaled.
+ */
+ newxprt->sc_sq_cq = ib_alloc_cq_any(dev, newxprt, sq_depth + ctxts,
IB_POLL_WORKQUEUE);
if (IS_ERR(newxprt->sc_sq_cq))
goto errout;
- newxprt->sc_rq_cq =
- ib_alloc_cq_any(dev, newxprt, rq_depth, IB_POLL_WORKQUEUE);
+ /* Every Receive WR is signaled. */
+ newxprt->sc_rq_cq = ib_alloc_cq_any(dev, newxprt, rq_depth,
+ IB_POLL_WORKQUEUE);
if (IS_ERR(newxprt->sc_rq_cq))
goto errout;
@@ -447,7 +455,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
qp_attr.qp_context = &newxprt->sc_xprt;
qp_attr.port_num = newxprt->sc_port_num;
qp_attr.cap.max_rdma_ctxs = ctxts;
- qp_attr.cap.max_send_wr = newxprt->sc_sq_depth - ctxts;
+ qp_attr.cap.max_send_wr = sq_depth;
qp_attr.cap.max_recv_wr = rq_depth;
qp_attr.cap.max_send_sge = newxprt->sc_max_send_sges;
qp_attr.cap.max_recv_sge = 1;
@@ -455,17 +463,20 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
qp_attr.qp_type = IB_QPT_RC;
qp_attr.send_cq = newxprt->sc_sq_cq;
qp_attr.recv_cq = newxprt->sc_rq_cq;
- dprintk(" cap.max_send_wr = %d, cap.max_recv_wr = %d\n",
- qp_attr.cap.max_send_wr, qp_attr.cap.max_recv_wr);
- dprintk(" cap.max_send_sge = %d, cap.max_recv_sge = %d\n",
- qp_attr.cap.max_send_sge, qp_attr.cap.max_recv_sge);
-
ret = rdma_create_qp(newxprt->sc_cm_id, newxprt->sc_pd, &qp_attr);
if (ret) {
trace_svcrdma_qp_err(newxprt, ret);
goto errout;
}
+ dprintk("svcrdma: cap.max_send_wr = %d, cap.max_recv_wr = %d\n",
+ qp_attr.cap.max_send_wr, qp_attr.cap.max_recv_wr);
+ dprintk(" cap.max_send_sge = %d, cap.max_recv_sge = %d\n",
+ qp_attr.cap.max_send_sge, qp_attr.cap.max_recv_sge);
+ dprintk(" send CQ depth = %d, recv CQ depth = %d\n",
+ sq_depth, rq_depth);
newxprt->sc_qp = newxprt->sc_cm_id->qp;
+ newxprt->sc_sq_depth = qp_attr.cap.max_send_wr;
+ atomic_set(&newxprt->sc_sq_avail, qp_attr.cap.max_send_wr);
if (!(dev->attrs.device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS))
newxprt->sc_snd_w_inv = false;
