On 11/23/2015 5:20 PM, Chuck Lever wrote:
Extra resources for handling backchannel requests have to be
pre-allocated when a transport instance is created. Set a limit.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
include/linux/sunrpc/svc_rdma.h | 5 +++++
net/sunrpc/xprtrdma/svc_rdma_transport.c | 6 +++++-
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index f869807..478aa30 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -178,6 +178,11 @@ struct svcxprt_rdma {
#define RPCRDMA_SQ_DEPTH_MULT 8
#define RPCRDMA_MAX_REQUESTS 32
#define RPCRDMA_MAX_REQ_SIZE 4096
+#if defined(CONFIG_SUNRPC_BACKCHANNEL)
Why is this a config option? Why wouldn't you always want
this? It's needed for any post-1990 NFS dialect.
+#define RPCRDMA_MAX_BC_REQUESTS 8
Why a constant 8? The forward channel value is apparently
configurable, just a few lines down.
+#else
+#define RPCRDMA_MAX_BC_REQUESTS 0
+#endif
#define RPCSVC_MAXPAYLOAD_RDMA RPCSVC_MAXPAYLOAD
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index b348b4a..01c7b36 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -923,8 +923,10 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
(size_t)RPCSVC_MAXPAGES);
newxprt->sc_max_sge_rd = min_t(size_t, devattr.max_sge_rd,
RPCSVC_MAXPAGES);
+ /* XXX: what if HCA can't support enough WRs for bc operation? */
newxprt->sc_max_requests = min((size_t)devattr.max_qp_wr,
- (size_t)svcrdma_max_requests);
+ (size_t)(svcrdma_max_requests +
+ RPCRDMA_MAX_BC_REQUESTS));
newxprt->sc_sq_depth = RPCRDMA_SQ_DEPTH_MULT * newxprt->sc_max_requests;
/*
@@ -964,7 +966,9 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
qp_attr.event_handler = qp_event_handler;
qp_attr.qp_context = &newxprt->sc_xprt;
qp_attr.cap.max_send_wr = newxprt->sc_sq_depth;
+ qp_attr.cap.max_send_wr += RPCRDMA_MAX_BC_REQUESTS;
qp_attr.cap.max_recv_wr = newxprt->sc_max_requests;
+ qp_attr.cap.max_recv_wr += RPCRDMA_MAX_BC_REQUESTS;
qp_attr.cap.max_send_sge = newxprt->sc_max_sge;
qp_attr.cap.max_recv_sge = newxprt->sc_max_sge;
qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
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