From: Chuck Lever <chuck.lever@xxxxxxxxxx> The original rationale for handling Receive completions in process context was to eliminate the use of a bottom-half-disabled spin lock. This was intended to simplify assumptions made in the Receive code paths and reduce lock contention. However, a completion handled during soft IRQ is considerably lower in average latency than taking a spin lock that disables bottom halves, since with soft IRQ, the completion interrupt no longer has to get scheduled onto a workqueue. Now that Receive contexts are pre-allocated and the RPC service thread scheduler is constant time, moving Receive completion processing to soft IRQ is safe and simple. Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> --- net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 4 ++-- net/sunrpc/xprtrdma/svc_rdma_transport.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c index 6191ce20f89e..4ee219924433 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c @@ -810,14 +810,14 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp) rqstp->rq_xprt_ctxt = NULL; ctxt = NULL; - spin_lock(&rdma_xprt->sc_rq_dto_lock); + spin_lock_bh(&rdma_xprt->sc_rq_dto_lock); ctxt = svc_rdma_next_recv_ctxt(&rdma_xprt->sc_rq_dto_q); if (ctxt) list_del(&ctxt->rc_list); else /* No new incoming requests, terminate the loop */ clear_bit(XPT_DATA, &xprt->xpt_flags); - spin_unlock(&rdma_xprt->sc_rq_dto_lock); + spin_unlock_bh(&rdma_xprt->sc_rq_dto_lock); /* Unblock the transport for the next receive */ svc_xprt_received(xprt); diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c index 2abd895046ee..7bd50efeeb4e 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c @@ -433,8 +433,8 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt) 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); + newxprt->sc_rq_cq = ib_alloc_cq_any(dev, newxprt, rq_depth, + IB_POLL_SOFTIRQ); if (IS_ERR(newxprt->sc_rq_cq)) goto errout;
