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Commit 124fa17d authored by Chuck Lever's avatar Chuck Lever Committed by Anna Schumaker
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xprtrdma: Pre-allocate Work Requests for backchannel 



Pre-allocate extra send and receive Work Requests needed to handle
backchannel receives and sends.

The transport doesn't know how many extra WRs to pre-allocate until
the xprt_setup_backchannel() call, but that's long after the WRs are
allocated during forechannel setup.

So, use a fixed value for now.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Reviewed-by: default avatarSagi Grimberg <sagig@mellanox.com>
Tested-By: default avatarDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent f531a5db

net/sunrpc/xprtrdma/backchannel.c

+4 −0
Original line number Diff line number Diff line
@@ -125,6 +125,9 @@ int xprt_rdma_bc_setup(struct rpc_xprt *xprt, unsigned int reqs) 
	 * Twice as many rpc_rqsts are prepared to ensure there is

	 * always an rpc_rqst available as soon as a reply is sent.

	 */

	if (reqs > RPCRDMA_BACKWARD_WRS >> 1)

		goto out_err;



	for (i = 0; i < (reqs << 1); i++) {

		rqst = kzalloc(sizeof(*rqst), GFP_KERNEL);

		if (!rqst) {
@@ -161,6 +164,7 @@ int xprt_rdma_bc_setup(struct rpc_xprt *xprt, unsigned int reqs) 
out_free:

	xprt_rdma_bc_destroy(xprt, reqs);



out_err:

	pr_err("RPC:       %s: setup backchannel transport failed\n", __func__);

	return -ENOMEM;

}

net/sunrpc/xprtrdma/verbs.c

+12 −2
Original line number Diff line number Diff line
@@ -568,6 +568,7 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia, 
	struct ib_device_attr *devattr = &ia->ri_devattr;

	struct ib_cq *sendcq, *recvcq;

	struct ib_cq_init_attr cq_attr = {};

	unsigned int max_qp_wr;

	int rc, err;



	if (devattr->max_sge < RPCRDMA_MAX_IOVS) {
@@ -576,18 +577,27 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia, 
		return -ENOMEM;

	}



	if (devattr->max_qp_wr <= RPCRDMA_BACKWARD_WRS) {

		dprintk("RPC:       %s: insufficient wqe's available\n",

			__func__);

		return -ENOMEM;

	}

	max_qp_wr = devattr->max_qp_wr - RPCRDMA_BACKWARD_WRS;



	/* check provider's send/recv wr limits */

	if (cdata->max_requests > devattr->max_qp_wr)

		cdata->max_requests = devattr->max_qp_wr;

	if (cdata->max_requests > max_qp_wr)

		cdata->max_requests = max_qp_wr;



	ep->rep_attr.event_handler = rpcrdma_qp_async_error_upcall;

	ep->rep_attr.qp_context = ep;

	ep->rep_attr.srq = NULL;

	ep->rep_attr.cap.max_send_wr = cdata->max_requests;

	ep->rep_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS;

	rc = ia->ri_ops->ro_open(ia, ep, cdata);

	if (rc)

		return rc;

	ep->rep_attr.cap.max_recv_wr = cdata->max_requests;

	ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;

	ep->rep_attr.cap.max_send_sge = RPCRDMA_MAX_IOVS;

	ep->rep_attr.cap.max_recv_sge = 1;

	ep->rep_attr.cap.max_inline_data = 0;

net/sunrpc/xprtrdma/xprt_rdma.h

+10 −0
Original line number Diff line number Diff line
@@ -101,6 +101,16 @@ struct rpcrdma_ep { 
 */

#define RPCRDMA_IGNORE_COMPLETION	(0ULL)



/* Pre-allocate extra Work Requests for handling backward receives

 * and sends. This is a fixed value because the Work Queues are

 * allocated when the forward channel is set up.

 */

#if defined(CONFIG_SUNRPC_BACKCHANNEL)

#define RPCRDMA_BACKWARD_WRS		(8)

#else

#define RPCRDMA_BACKWARD_WRS		(0)

#endif



/* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV

 *

 * The below structure appears at the front of a large region of kmalloc'd