Commit c558d475 authored by Chuck Lever's avatar Chuck Lever
Browse files

svcrdma: Maintain a Receive water mark 



Post more Receives when the number of pending Receives drops below
a water mark. The batch mechanism is disabled if the underlying
device cannot support a reasonably-sized Receive Queue.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 7b748c30

include/linux/sunrpc/svc_rdma.h

+2 −0
Original line number Diff line number Diff line
@@ -94,6 +94,8 @@ struct svcxprt_rdma { 
	spinlock_t	     sc_rw_ctxt_lock;

	struct list_head     sc_rw_ctxts;



	u32		     sc_pending_recvs;

	u32		     sc_recv_batch;

	struct list_head     sc_rq_dto_q;

	spinlock_t	     sc_rq_dto_lock;

	struct ib_qp         *sc_qp;

net/sunrpc/xprtrdma/svc_rdma_recvfrom.c

+8 −2
Original line number Diff line number Diff line
@@ -285,6 +285,7 @@ static bool svc_rdma_refresh_recvs(struct svcxprt_rdma *rdma, 
		ctxt->rc_temp = temp;

		ctxt->rc_recv_wr.next = recv_chain;

		recv_chain = &ctxt->rc_recv_wr;

		rdma->sc_pending_recvs++;

	}

	if (!recv_chain)

		return false;
@@ -302,6 +303,8 @@ static bool svc_rdma_refresh_recvs(struct svcxprt_rdma *rdma, 
		bad_wr = bad_wr->next;

		svc_rdma_recv_ctxt_put(rdma, ctxt);

	}

	/* Since we're destroying the xprt, no need to reset

	 * sc_pending_recvs. */

	return false;

}
@@ -328,6 +331,8 @@ static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc) 
	struct ib_cqe *cqe = wc->wr_cqe;

	struct svc_rdma_recv_ctxt *ctxt;



	rdma->sc_pending_recvs--;



	/* WARNING: Only wc->wr_cqe and wc->status are reliable */

	ctxt = container_of(cqe, struct svc_rdma_recv_ctxt, rc_cqe);
@@ -344,7 +349,8 @@ static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc) 
	 * to reduce the likelihood of replayed requests once the

	 * client reconnects.

	 */

	if (!svc_rdma_refresh_recvs(rdma, 1, false))

	if (rdma->sc_pending_recvs < rdma->sc_max_requests)

		if (!svc_rdma_refresh_recvs(rdma, rdma->sc_recv_batch, false))

			goto flushed;



	/* All wc fields are now known to be valid */

net/sunrpc/xprtrdma/svc_rdma_transport.c

+4 −1
Original line number Diff line number Diff line
@@ -407,11 +407,14 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt) 
	newxprt->sc_max_req_size = svcrdma_max_req_size;

	newxprt->sc_max_requests = svcrdma_max_requests;

	newxprt->sc_max_bc_requests = svcrdma_max_bc_requests;

	rq_depth = newxprt->sc_max_requests + newxprt->sc_max_bc_requests;

	newxprt->sc_recv_batch = RPCRDMA_MAX_RECV_BATCH;

	rq_depth = newxprt->sc_max_requests + newxprt->sc_max_bc_requests +

		   newxprt->sc_recv_batch;

	if (rq_depth > dev->attrs.max_qp_wr) {

		pr_warn("svcrdma: reducing receive depth to %d\n",

			dev->attrs.max_qp_wr);

		rq_depth = dev->attrs.max_qp_wr;

		newxprt->sc_recv_batch = 1;

		newxprt->sc_max_requests = rq_depth - 2;

		newxprt->sc_max_bc_requests = 2;

	}