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: Chuck Lever <[email protected]> --- net/sunrpc/xprtrdma/backchannel.c | 4 ++++ net/sunrpc/xprtrdma/verbs.c | 14 ++++++++++++-- net/sunrpc/xprtrdma/xprt_rdma.h | 10 ++++++++++ 3 files changed, 26 insertions(+), 2 deletions(-) diff --git a/net/sunrpc/xprtrdma/backchannel.c b/net/sunrpc/xprtrdma/backchannel.c index c0a42ad..f5c7122 100644 --- a/net/sunrpc/xprtrdma/backchannel.c +++ b/net/sunrpc/xprtrdma/backchannel.c @@ -123,6 +123,9 @@ 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) { @@ -159,6 +162,7 @@ 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; } diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index 1e4a948..133c720 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -614,6 +614,7 @@ 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) { @@ -622,18 +623,27 @@ 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; diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index 2ca0567..37d0d7f 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -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 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
