From: Chuck Lever <chuck.lever@oracle.com>
Date: Mon, 28 Aug 2017 15:06:06 -0400
Subject: svcrdma: Limit RQ depth
Patch-mainline: v4.14-rc1
Git-commit: 5a25bfd28c321e522dbe8083ad6219fa2a820610
References: bsc#1081515
Ensure that the chosen Receive Queue depth for a newly created
transport does not overrun the QP WR limit of the underlying device.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
net/sunrpc/xprtrdma/svc_rdma_transport.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -167,8 +167,8 @@ static bool svc_rdma_prealloc_ctxts(stru
{
unsigned int i;
- /* Each RPC/RDMA credit can consume a number of send
- * and receive WQEs. One ctxt is allocated for each.
+ /* Each RPC/RDMA credit can consume one Receive and
+ * one Send WQE at the same time.
*/
i = xprt->sc_sq_depth + xprt->sc_rq_depth;
@@ -909,13 +909,18 @@ static struct svc_xprt *svc_rdma_accept(
newxprt->sc_max_sge = min((size_t)dev->attrs.max_sge,
(size_t)RPCSVC_MAXPAGES);
newxprt->sc_max_req_size = svcrdma_max_req_size;
- newxprt->sc_max_requests = min_t(u32, dev->attrs.max_qp_wr,
- svcrdma_max_requests);
- newxprt->sc_fc_credits = cpu_to_be32(newxprt->sc_max_requests);
- newxprt->sc_max_bc_requests = min_t(u32, dev->attrs.max_qp_wr,
- svcrdma_max_bc_requests);
+ newxprt->sc_max_requests = svcrdma_max_requests;
+ newxprt->sc_max_bc_requests = svcrdma_max_bc_requests;
newxprt->sc_rq_depth = newxprt->sc_max_requests +
newxprt->sc_max_bc_requests;
+ if (newxprt->sc_rq_depth > dev->attrs.max_qp_wr) {
+ pr_warn("svcrdma: reducing receive depth to %d\n",
+ dev->attrs.max_qp_wr);
+ newxprt->sc_rq_depth = dev->attrs.max_qp_wr;
+ newxprt->sc_max_requests = newxprt->sc_rq_depth - 2;
+ newxprt->sc_max_bc_requests = 2;
+ }
+ newxprt->sc_fc_credits = cpu_to_be32(newxprt->sc_max_requests);
newxprt->sc_sq_depth = newxprt->sc_rq_depth;
atomic_set(&newxprt->sc_sq_avail, newxprt->sc_sq_depth);