From owner-freebsd-arch@FreeBSD.ORG Thu Jan 6 21:30:31 2011 Return-Path: Delivered-To: arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C2EAF106564A; Thu, 6 Jan 2011 21:30:31 +0000 (UTC) (envelope-from wollman@hergotha.csail.mit.edu) Received: from hergotha.csail.mit.edu (wollman-1-pt.tunnel.tserv4.nyc4.ipv6.he.net [IPv6:2001:470:1f06:ccb::2]) by mx1.freebsd.org (Postfix) with ESMTP id 590328FC1E; Thu, 6 Jan 2011 21:30:31 +0000 (UTC) Received: from hergotha.csail.mit.edu (localhost [127.0.0.1]) by hergotha.csail.mit.edu (8.14.4/8.14.4) with ESMTP id p06LUUvp006270; Thu, 6 Jan 2011 16:30:30 -0500 (EST) (envelope-from wollman@hergotha.csail.mit.edu) Received: (from wollman@localhost) by hergotha.csail.mit.edu (8.14.4/8.14.4/Submit) id p06LUUmA006269; Thu, 6 Jan 2011 16:30:30 -0500 (EST) (envelope-from wollman) Date: Thu, 6 Jan 2011 16:30:30 -0500 (EST) From: Garrett Wollman Message-Id: <201101062130.p06LUUmA006269@hergotha.csail.mit.edu> To: zml@freebsd.org X-Newsgroups: mit.lcs.mail.freebsd-arch In-Reply-To: <20110106194030.GA27507@famine.west.isilon.com> References: <20110103220153.69cf59e0@kan.dnsalias.net> <20110104082252.45bb5e7f@kan.dnsalias.net> Organization: none X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.6 (hergotha.csail.mit.edu [127.0.0.1]); Thu, 06 Jan 2011 16:30:30 -0500 (EST) X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED autolearn=disabled version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on hergotha.csail.mit.edu Cc: arch@freebsd.org Subject: Re: Linux kernel compatability X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 06 Jan 2011 21:30:31 -0000 In article <20110106194030.GA27507@famine.west.isilon.com>, zml@freebsd.org writes: >Unlike 4 years ago, we now have staffed IB personnel that will be >working with the code in the FreeBSD tree. We have every incentive to >make sure IB stays working in head - it saves us so much time when we >merge. And, for those who heard of our recent acquisition by EMC, we >have a nod from our parent company to keep doing what we're doing. > >I hope this mitigates most of the non-technical concerns. I *hope* we are clear that we want Infiniband support in the tree. I don't think we agree about whether we want the compatibility layer to grow into a general "Linux KPI support layer" or simply part of the Infiniband stack in parallel with the adaptation layers used by lots of other vendor-supported drivers. So long as it remains what it currently is -- just the interfaces you need to make your code work -- then there is less chance of it becoming a maintenance problem in the future. On the other hand, we already have this issue with other bits of Linux kernel code that have been ported, more or less successfully, and their own (much thinner) compatibility glue layers. The argument that having only one such layer is better than having many is not unreasonable; it's just not clear to me that this is maintainable. -GAWollman