From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268378AbUJTETj (ORCPT ); Wed, 20 Oct 2004 00:19:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266034AbUJTETg (ORCPT ); Wed, 20 Oct 2004 00:19:36 -0400 Received: from mustang.oldcity.dca.net ([216.158.38.3]:6571 "HELO mustang.oldcity.dca.net") by vger.kernel.org with SMTP id S269503AbUJTES2 (ORCPT ); Wed, 20 Oct 2004 00:18:28 -0400 Subject: Re: Linux v2.6.9 and GPL Buyout From: Lee Revell To: Ryan Anderson Cc: "Jeff V. Merkey" , Dax Kelson , Linus Torvalds , Kernel Mailing List In-Reply-To: <20041020034524.GD10638@michonline.com> References: <417550FB.8020404@drdos.com> <1098218286.8675.82.camel@mentorng.gurulabs.com> <41757478.4090402@drdos.com> <20041020034524.GD10638@michonline.com> Content-Type: text/plain Message-Id: <1098245904.23628.84.camel@krustophenia.net> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Wed, 20 Oct 2004 00:18:25 -0400 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2004-10-19 at 23:45, Ryan Anderson wrote: > RCU - originally a paper, implemented in Dynix and in other operating > systems from the paper (and patent), implemented in Linux as well. You could also make a strong argument that that patent is invalid because RCU is obvious. I was doing this with perl and SQL before I ever heard of RCU. If you don't want to lock a table (or didn't realize SQL had such a thing as table locking :-) you just fetch a value, make some calculation on it, then do the update iff that value has not changed. If it has changed you fetch the new value and go back to step 1. It's just the obvious way to update a shared data structure if you have cmpxchg but no locking. Lee