From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D4A3C433EF for ; Wed, 2 Mar 2022 07:51:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239876AbiCBHwg (ORCPT ); Wed, 2 Mar 2022 02:52:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233208AbiCBHwg (ORCPT ); Wed, 2 Mar 2022 02:52:36 -0500 Received: from out30-54.freemail.mail.aliyun.com (out30-54.freemail.mail.aliyun.com [115.124.30.54]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 951651C133; Tue, 1 Mar 2022 23:51:49 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04423;MF=alibuda@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0V61jDA6_1646207506; Received: from localhost(mailfrom:alibuda@linux.alibaba.com fp:SMTPD_---0V61jDA6_1646207506) by smtp.aliyun-inc.com(127.0.0.1); Wed, 02 Mar 2022 15:51:47 +0800 Date: Wed, 2 Mar 2022 15:51:46 +0800 From: "D. Wythe" To: Wen Gu Cc: kgraul@linux.ibm.com, kuba@kernel.org, davem@davemloft.net, netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-rdma@vger.kernel.org Subject: Re: [PATCH net] net/smc: fix unexpected SMC_CLC_DECL_ERR_REGRMB error Message-ID: <20220302075146.GA29189@e02h04389.eu6sqa> Reply-To: "D. Wythe" References: <1646140644-121649-1-git-send-email-alibuda@linux.alibaba.com> <82bd43af-1d90-4395-b868-4a045bf4a47b@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=gb2312 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <82bd43af-1d90-4395-b868-4a045bf4a47b@linux.alibaba.com> User-Agent: Mutt/1.5.21 (2010-09-15) Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org On Wed, Mar 02, 2022 at 03:28:32PM +0800, Wen Gu wrote: > > > ÔÚ 2022/3/1 ÏÂÎç9:17, D. Wythe дµÀ: > >From: "D. Wythe" > > > >Remove connections from link group is not synchronous with handling > >SMC_LLC_DELETE_RKEY, which means that even the number of connections is > >less that SMC_RMBS_PER_LGR_MAX, it does not mean that the connection can > >register rtoken successfully later, in other words, the rtoken entry may > >have not been released. This will cause an unexpected > >SMC_CLC_DECL_ERR_REGRMB to be reported, and then ths smc connection have > >to fallback to TCP. > > > > > IMHO, if there are SMC_RMBS_PER_LGR_MAX connections in the link group now, > one of them is being removed and here comes a new connection at this moment, > then: > > (1) without this patch, the new connection will be added into the old link group > but fallback if the removing connection has not finished unregistering its rmb. > > (2) with this patch, a new link group will be created and the new connection > will be added into the new link group. > > I am wondering if (1) should be considered as a issue, or just a bydesign? > If it is a issue, I think this patch works, Thanks! We should always be willing to improve the success rate of the SMC connection, creating a new group is not a side effect of this patch, it actually dues to the state bewteen connections that can not achieve clock synchronization. In fact, it can happen in any times. Thanks.