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 X-Spam-Level: X-Spam-Status: No, score=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9236EC34047 for ; Wed, 19 Feb 2020 14:36:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6886124670 for ; Wed, 19 Feb 2020 14:36:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="AkRPBfR4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727912AbgBSOgI (ORCPT ); Wed, 19 Feb 2020 09:36:08 -0500 Received: from smtp-fw-6001.amazon.com ([52.95.48.154]:6359 "EHLO smtp-fw-6001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727875AbgBSOgI (ORCPT ); Wed, 19 Feb 2020 09:36:08 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1582122967; x=1613658967; h=subject:to:cc:references:from:message-id:date: mime-version:in-reply-to:content-transfer-encoding; bh=U4Itg1zQSSKKkGlXvowm/SO5w3sG0Q/ehdfK+NfvOdY=; b=AkRPBfR4/IjTy0SAGkP4fjryISotKEudJAuHycFmlspoXQcjhsc63oSw EzUZvkg5iUVnd40AkyCnLS75x5jIp9pmQ5Au284Jmf5lXntogUrKGXQZ8 n0NIzrIAZ/qpL55RYN6zOg0LcAosaP9VAyuRt851Ogsx1LcGe8cmkdptG s=; IronPort-SDR: bTXKQ0aeAh7xfJHeQNjyyRZXCZf2PJdPW4aG80UqUrbQu4RBsCpiBN8NS+mHLh7MTVK1BoW4eO 4VID/r+OYo2A== X-IronPort-AV: E=Sophos;i="5.70,459,1574121600"; d="scan'208";a="18577484" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-1d-9ec21598.us-east-1.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-6001.iad6.amazon.com with ESMTP; 19 Feb 2020 14:35:54 +0000 Received: from EX13MTAUEA002.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan3.iad.amazon.com [10.40.159.166]) by email-inbound-relay-1d-9ec21598.us-east-1.amazon.com (Postfix) with ESMTPS id 119CAA2B1E; Wed, 19 Feb 2020 14:35:52 +0000 (UTC) Received: from EX13D19EUB003.ant.amazon.com (10.43.166.69) by EX13MTAUEA002.ant.amazon.com (10.43.61.77) with Microsoft SMTP Server (TLS) id 15.0.1236.3; Wed, 19 Feb 2020 14:35:52 +0000 Received: from 8c85908914bf.ant.amazon.com (10.43.162.50) by EX13D19EUB003.ant.amazon.com (10.43.166.69) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Wed, 19 Feb 2020 14:35:45 +0000 Subject: Re: RDMA device renames and node description To: Dennis Dalessandro , Leon Romanovsky CC: "linux-rdma@vger.kernel.org" , Jason Gunthorpe , Honggang LI , Gal Pressman References: <5ae69feb-5543-b203-2f1b-df5fe3bdab2b@intel.com> <20200218140444.GB8816@unreal> <1fcc873b-3f67-2325-99cc-21d90edd2058@intel.com> <20200219071129.GD15239@unreal> From: Gal Pressman Message-ID: <67915d24-149a-e940-1f0b-a173eb4aca84@amazon.com> Date: Wed, 19 Feb 2020 16:35:40 +0200 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.43.162.50] X-ClientProxiedBy: EX13D36UWA002.ant.amazon.com (10.43.160.24) To EX13D19EUB003.ant.amazon.com (10.43.166.69) Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 19/02/2020 16:14, Dennis Dalessandro wrote: > On 2/19/2020 2:11 AM, Leon Romanovsky wrote: >> On Tue, Feb 18, 2020 at 12:11:47PM -0500, Dennis Dalessandro wrote: >>> On 2/18/2020 9:04 AM, Leon Romanovsky wrote: >>>> On Fri, Feb 14, 2020 at 01:13:53PM -0500, Dennis Dalessandro wrote: >> ABI breakage is a strong word, luckily enough it is not defined at all. >> We never considered dmesg prints, device names, device ordering as an >> ABI. You can't rely on debug features too, they can disappear too. > > Agree, it is a strong word and we can call it what you want. The point is you > should be able to rely on the node description not being changed out from under > you unnecessarily though. We aren't talking about a debug feature here but a > core feature to real world deployments. > > Could you envision a patch to a user space library that just changes a devices > hostname to something that was HW specific because it makes scripting easier? I > contend that in some cases the node description remaining constant is just as > important. > >> So the bottom line, the expectation that distro should fix all broken >> software before enabling device renaming and their bugs are not excuse >> to declare ABI breakage. > > Again, call it what you want, but you can't deny this change to force the rename > by default has not broken things. For the record I'm not even talking about PSM2 > here. There are other, more far reaching implications. It's not just PSM2, it broke our libfabric provider and apparently MVAPICH as well: http://mailman.cse.ohio-state.edu/pipermail/mvapich-discuss/2020-January/006960.html Regarding the issue you described, why not disable the rename on the upgrade path and only enable it for fresh installations?