From owner-freebsd-arch@FreeBSD.ORG Fri Feb 20 09:46:03 2004 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 66C8916A4CE for ; Fri, 20 Feb 2004 09:46:03 -0800 (PST) Received: from carver.gumbysoft.com (carver.gumbysoft.com [66.220.23.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id 60A2C43D1F for ; Fri, 20 Feb 2004 09:46:03 -0800 (PST) (envelope-from dwhite@gumbysoft.com) Received: by carver.gumbysoft.com (Postfix, from userid 1000) id 5654472DBF; Fri, 20 Feb 2004 09:46:03 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by carver.gumbysoft.com (Postfix) with ESMTP id 5191572DB5; Fri, 20 Feb 2004 09:46:03 -0800 (PST) Date: Fri, 20 Feb 2004 09:46:03 -0800 (PST) From: Doug White To: Doug Rabson In-Reply-To: <1077208338.9856.1.camel@builder02.qubesoft.com> Message-ID: <20040220094342.W60703@carver.gumbysoft.com> References: <1077137806.28133.10.camel@herring.nlsystems.com> <1077208338.9856.1.camel@builder02.qubesoft.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII cc: Peter A Jonsson cc: freebsd-arch@freebsd.org Subject: Re: Read Copy Update X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Feb 2004 17:46:03 -0000 On Thu, 19 Feb 2004, Doug Rabson wrote: > On Thu, 2004-02-19 at 16:26, Peter A Jonsson wrote: > > > I imagine that a FreeBSD implementation of RCU wouldn't actually be too > > > hard and it might be well worth it as an alternative way of managing > > > concurrency, e.g. for the routing cache and the name cache (and probably > > > lots of other things). > > > > Alan Cox pointed out[1] that there was a patent problem (US Patent > > #05442758 [2]) with RCU which prevented inclusion in the Linux > > kernel. This was solved[3] by granting the right to use it in GPL > > software according to my understanding. Isn't this a problem for > > FreeBSD? > > That would be a problem unless the patent owner (Sequent, i.e. IBM) > could be encouraged to grant a similar license for BSD software. Note that SCO is trying to claim that RCU is derviative of SysV, so it might be a good idea to steer clear of this until that issue is resolved... which might be a while. :) -- Doug White | FreeBSD: The Power to Serve dwhite@gumbysoft.com | www.FreeBSD.org