Return-Path: Received: from p3plsmtpa11-04.prod.phx3.secureserver.net ([68.178.252.105]:47884 "EHLO p3plsmtpa11-04.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751041AbdBWTub (ORCPT ); Thu, 23 Feb 2017 14:50:31 -0500 Subject: Re: [PATCH 1/4] sunrpc: flag transports as using IETF approved congestion control protocols To: Jeff Layton , bfields@fieldses.org, trond.myklebust@primarydata.com References: <20170223170337.10686-1-jlayton@redhat.com> <20170223170337.10686-2-jlayton@redhat.com> Cc: schumaker.anna@gmail.com, linux-nfs@vger.kernel.org From: Tom Talpey Message-ID: <2152dfdf-f847-2511-1600-6499b6ea9708@talpey.com> Date: Thu, 23 Feb 2017 14:42:24 -0500 MIME-Version: 1.0 In-Reply-To: <20170223170337.10686-2-jlayton@redhat.com> Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: On 2/23/2017 12:03 PM, Jeff Layton wrote: > Signed-off-by: Jeff Layton > --- > include/linux/sunrpc/svc_xprt.h | 1 + > net/sunrpc/svcsock.c | 1 + > net/sunrpc/xprtrdma/svc_rdma_transport.c | 2 ++ There's a possibly-important detail here. Not all RDMA transports have "IETF-approved congestion control", for example, RoCEv1. However, iWARP and (arguably) RoCEv2 do. On the other hand, as a nonroutable protocol, RoCEv1 may not fall under this restriction. Net-net, inspecting only the RDMA attribute of the transport may be insufficient here. It could be argued however that the xprtrdma layer, with its rpcrdma crediting, provides such congestion. But that needs to be made explicit, and perhaps, discussed in IETF. Initially, I think it would be important to flag this as a point for the future. For now, it may be best to flag RoCEv1 as not supporting congestion. Tom. > 3 files changed, 4 insertions(+) > > diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h > index 7440290f64ac..f8aa9452b63c 100644 > --- a/include/linux/sunrpc/svc_xprt.h > +++ b/include/linux/sunrpc/svc_xprt.h > @@ -67,6 +67,7 @@ struct svc_xprt { > #define XPT_CACHE_AUTH 11 /* cache auth info */ > #define XPT_LOCAL 12 /* connection from loopback interface */ > #define XPT_KILL_TEMP 13 /* call xpo_kill_temp_xprt before closing */ > +#define XPT_CONG_CTRL 14 /* IETF approved congestion control protocol */ > > struct svc_serv *xpt_server; /* service for transport */ > atomic_t xpt_reserved; /* space on outq that is rsvd */ > diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c > index de066acdb34e..1956b8b96b2d 100644 > --- a/net/sunrpc/svcsock.c > +++ b/net/sunrpc/svcsock.c > @@ -1306,6 +1306,7 @@ static void svc_tcp_init(struct svc_sock *svsk, struct svc_serv *serv) > svc_xprt_init(sock_net(svsk->sk_sock->sk), &svc_tcp_class, > &svsk->sk_xprt, serv); > set_bit(XPT_CACHE_AUTH, &svsk->sk_xprt.xpt_flags); > + set_bit(XPT_CONG_CTRL, &svsk->sk_xprt.xpt_flags); > if (sk->sk_state == TCP_LISTEN) { > dprintk("setting up TCP socket for listening\n"); > set_bit(XPT_LISTENER, &svsk->sk_xprt.xpt_flags); > diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c > index 39652d390a9c..96b4797c2c54 100644 > --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c > +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c > @@ -571,6 +571,8 @@ static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv, > spin_lock_init(&cma_xprt->sc_ctxt_lock); > spin_lock_init(&cma_xprt->sc_map_lock); > > + set_bit(XPT_CONG_CTRL, &cma_xprt->sc_xprt.xpt_flags); > + > if (listener) > set_bit(XPT_LISTENER, &cma_xprt->sc_xprt.xpt_flags); > >