> On Jun 5, 2018, at 2:14 PM, Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Some devices have vastly different max sge depths for RQs vs SQs. So add
> queue-specific attributes so applications can take full advantage of
> hw capabilities.
:
:
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
> index 96cc8f6..cb3471b 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
> @@ -736,7 +736,8 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
>
> /* Qualify the transport resource defaults with the
> * capabilities of this particular device */
> - newxprt->sc_max_sge = min((size_t)dev->attrs.max_sge,
> + newxprt->sc_max_sge = min3((size_t)dev->attrs.max_send_sge,
> + (size_t)dev->attrs.max_recv_sge,
> (size_t)RPCSVC_MAXPAGES);
A patch coming in v4.18 replaces sc_max_sge with sc_max_send_sge.
Another patch changes the NFS server's Receive path to require
only a single SGE, so min3 won't be necessary here.
Shouldn't be difficult to sort out.
> newxprt->sc_max_req_size = svcrdma_max_req_size;
> newxprt->sc_max_requests = svcrdma_max_requests;
> diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
> index fe5eaca..7ffa388 100644
> --- a/net/sunrpc/xprtrdma/verbs.c
> +++ b/net/sunrpc/xprtrdma/verbs.c
> @@ -504,7 +504,7 @@
> struct ib_cq *sendcq, *recvcq;
> int rc;
>
> - max_sge = min_t(unsigned int, ia->ri_device->attrs.max_sge,
> + max_sge = min_t(unsigned int, ia->ri_device->attrs.max_send_sge,
> RPCRDMA_MAX_SEND_SGES);
That should work fine.
> if (max_sge < RPCRDMA_MIN_SEND_SGES) {
> pr_warn("rpcrdma: HCA provides only %d send SGEs\n", max_sge);
> --
> 1.8.3.1
>
--
Chuck Lever
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