Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261350AbVDZGNG (ORCPT ); Tue, 26 Apr 2005 02:13:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261356AbVDZGNF (ORCPT ); Tue, 26 Apr 2005 02:13:05 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:36524 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S261350AbVDZGMs (ORCPT ); Tue, 26 Apr 2005 02:12:48 -0400 Date: Tue, 26 Apr 2005 07:12:36 +0100 From: Christoph Hellwig To: Roland Dreier Cc: Andrew Morton , timur.tabi@ammasso.com, hch@infradead.org, hozer@hozed.org, linux-kernel@vger.kernel.org, openib-general@openib.org Subject: Re: [PATCH][RFC][0/4] InfiniBand userspace verbs implementation Message-ID: <20050426061236.GA27220@infradead.org> Mail-Followup-To: Christoph Hellwig , Roland Dreier , Andrew Morton , timur.tabi@ammasso.com, hozer@hozed.org, linux-kernel@vger.kernel.org, openib-general@openib.org References: <4263DEC5.5080909@ammasso.com> <20050418164316.GA27697@infradead.org> <4263E445.8000605@ammasso.com> <20050423194421.4f0d6612.akpm@osdl.org> <426BABF4.3050205@ammasso.com> <52is2bvvz5.fsf@topspin.com> <20050425135401.65376ce0.akpm@osdl.org> <521x8yv9vb.fsf@topspin.com> <20050425151459.1f5fb378.akpm@osdl.org> <52r7gytnfn.fsf@topspin.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52r7gytnfn.fsf@topspin.com> User-Agent: Mutt/1.4.1i X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1282 Lines: 24 On Mon, Apr 25, 2005 at 05:02:36PM -0700, Roland Dreier wrote: > The idea is that applications manage the lifetime of pinned memory > regions. They can do things like post multiple I/O operations without > any page-walking overhead, or pass a buffer descriptor to a remote > host who will send data at some indeterminate time in the future. In > addition, InfiniBand has the notion of atomic operations, so a cluster > application may be using some memory region to implement a global lock. > > This might not be the most kernel-friendly design but it is pretty > deeply ingrained in the design of RDMA transports like InfiniBand and > iWARP (RDMA over IP). Actuallky, no it isn't. All these transports would work just fine with the mmap a character device to hand out memory from the kernel approach I told you to use multiple times and Andrew mentioned in this thread aswell. What doesn't work with that design are the braindead designed by comittee APIs in the RDMA world - but I don't think we should care about them too much. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/