Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:46121 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752229AbaKJPFe (ORCPT ); Mon, 10 Nov 2014 10:05:34 -0500 Date: Mon, 10 Nov 2014 10:05:29 -0500 From: "J. Bruce Fields" To: Chuck Lever Cc: Anna Schumaker , linux-rdma@vger.kernel.org, Linux NFS Mailing List Subject: Re: [PATCH v2 06/10] xprtrdma: Enable pad optimization Message-ID: <20141110150529.GB32702@fieldses.org> References: <20141109010328.8806.5861.stgit@manet.1015granger.net> <20141109011453.8806.31817.stgit@manet.1015granger.net> <5460CD53.1080301@Netapp.com> <89410A6C-693C-4FB2-A0AB-5698803F3AFC@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <89410A6C-693C-4FB2-A0AB-5698803F3AFC@oracle.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, Nov 10, 2014 at 08:54:27AM -0600, Chuck Lever wrote: > > On Nov 10, 2014, at 8:36 AM, Anna Schumaker wrote: > > > Hey Chuck, > > > > > > On 11/08/2014 08:14 PM, Chuck Lever wrote: > >> The Linux NFS/RDMA server used to reject NFSv3 WRITE requests when > >> pad optimization was enabled. That bug was fixed by commit > >> e560e3b510d2 ("svcrdma: Add zero padding if the client doesn't send > >> it"). > > > > Do we need to worry about backwards compatibility with servers that don't have this patch? > > My impression is that we have a window where the server is assumed not > to work and thus is not enabled in distributions, and that therefore > changes like this are allowed. I could be wrong. Bruce, any guidance > on this? > > In any event, if things break, they break immediately, and the fix is > simply to set this feature flag via /proc. I don't think there's any hard-and-fast rule here, but my impression is that nfs/rdma still isn't widely used, even less so with linux knfsd, so on balance it's probably not worth much to humor older servers. --b. > > > > > > Anna > > > >> > >> We can now enable pad optimization on the client, which helps > >> performance and is supported now by both Linux and Solaris servers. > >> > >> Signed-off-by: Chuck Lever > >> --- > >> net/sunrpc/xprtrdma/transport.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c > >> index cfe9a81..8ed2576 100644 > >> --- a/net/sunrpc/xprtrdma/transport.c > >> +++ b/net/sunrpc/xprtrdma/transport.c > >> @@ -73,7 +73,7 @@ static unsigned int xprt_rdma_max_inline_read = RPCRDMA_DEF_INLINE; > >> static unsigned int xprt_rdma_max_inline_write = RPCRDMA_DEF_INLINE; > >> static unsigned int xprt_rdma_inline_write_padding; > >> static unsigned int xprt_rdma_memreg_strategy = RPCRDMA_FRMR; > >> - int xprt_rdma_pad_optimize = 0; > >> + int xprt_rdma_pad_optimize = 1; > >> > >> #ifdef RPC_DEBUG > >> > >> > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > >> the body of a message to majordomo@vger.kernel.org > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > Chuck Lever > chuck[dot]lever[at]oracle[dot]com > > >