Return-Path: Received: from mail-oi0-f44.google.com ([209.85.218.44]:34662 "EHLO mail-oi0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752211AbbKXBgC (ORCPT ); Mon, 23 Nov 2015 20:36:02 -0500 Received: by oies6 with SMTP id s6so1560937oie.1 for ; Mon, 23 Nov 2015 17:36:01 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <5653BB2C.4040209@talpey.com> References: <20151123221738.13040.26277.stgit@klimt.1015granger.net> <20151123222030.13040.19373.stgit@klimt.1015granger.net> <5653B1A6.3010707@talpey.com> <5653BB2C.4040209@talpey.com> Date: Mon, 23 Nov 2015 20:36:01 -0500 Message-ID: Subject: Re: [PATCH v1 2/8] svcrdma: Define maximum number of backchannel requests From: Trond Myklebust To: Tom Talpey Cc: Chuck Lever , Linux RDMA Mailing List , Linux NFS Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, Nov 23, 2015 at 8:19 PM, Tom Talpey wrote: > On 11/23/2015 8:09 PM, Chuck Lever wrote: >> >> >>> On Nov 23, 2015, at 7:39 PM, Tom Talpey wrote: >>> >>> On 11/23/2015 5:20 PM, Chuck Lever wrote: >>>> >>>> Extra resources for handling backchannel requests have to be >>>> pre-allocated when a transport instance is created. Set a limit. >>>> >>>> Signed-off-by: Chuck Lever >>>> --- >>>> include/linux/sunrpc/svc_rdma.h | 5 +++++ >>>> net/sunrpc/xprtrdma/svc_rdma_transport.c | 6 +++++- >>>> 2 files changed, 10 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/include/linux/sunrpc/svc_rdma.h >>>> b/include/linux/sunrpc/svc_rdma.h >>>> index f869807..478aa30 100644 >>>> --- a/include/linux/sunrpc/svc_rdma.h >>>> +++ b/include/linux/sunrpc/svc_rdma.h >>>> @@ -178,6 +178,11 @@ struct svcxprt_rdma { >>>> #define RPCRDMA_SQ_DEPTH_MULT 8 >>>> #define RPCRDMA_MAX_REQUESTS 32 >>>> #define RPCRDMA_MAX_REQ_SIZE 4096 >>>> +#if defined(CONFIG_SUNRPC_BACKCHANNEL) >>> >>> >>> Why is this a config option? Why wouldn't you always want >>> this? It's needed for any post-1990 NFS dialect. >> >> >> I think some distros want to be able to compile out NFSv4.x >> on small systems, and take all the backchannel cruft with it. > > > So shouldn't it follow the NFSv4.x config options then? It does. Why the question?