Return-Path: Received: from p3plsmtpa11-10.prod.phx3.secureserver.net ([68.178.252.111]:55389 "EHLO p3plsmtpa11-10.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753215AbbGNTAy (ORCPT ); Tue, 14 Jul 2015 15:00:54 -0400 Message-ID: <55A55C63.50403@talpey.com> Date: Tue, 14 Jul 2015 15:00:51 -0400 From: Tom Talpey MIME-Version: 1.0 To: Chuck Lever , linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Subject: Re: [PATCH v2 07/14] xprtrdma: Remove logic that constructs RDMA_MSGP type calls References: <20150713160617.17630.97475.stgit@manet.1015granger.net> <20150713163048.17630.86326.stgit@manet.1015granger.net> In-Reply-To: <20150713163048.17630.86326.stgit@manet.1015granger.net> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: On 7/13/2015 12:30 PM, Chuck Lever wrote: > RDMA_MSGP type calls insert a zero pad in the middle of the RPC > message to align the RPC request's data payload to the server's > alignment preferences. A server can then "page flip" the payload > into place to avoid a data copy in certain circumstances. However: >... > > Clean up the marshaling code by removing the logic that constructs > RDMA_MSGP type calls. This also reduces the maximum send iovec size > from four to just two elements. > > diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h > index 8219011..0b50103 100644 > --- a/net/sunrpc/xprtrdma/xprt_rdma.h > +++ b/net/sunrpc/xprtrdma/xprt_rdma.h ...> > +#define RPCRDMA_MAX_IOVS (4) > + So, shouldn't this constant be "2"? The extra 2 iov's were used only for constructing the pad.