Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 21 Mar 2001 04:06:02 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 21 Mar 2001 04:05:51 -0500 Received: from ppp0.ocs.com.au ([203.34.97.3]:24588 "HELO mail.ocs.com.au") by vger.kernel.org with SMTP id ; Wed, 21 Mar 2001 04:05:45 -0500 X-Mailer: exmh version 2.1.1 10/15/1999 From: Keith Owens To: george anzinger cc: nigel@nrg.org, Rusty Russell , linux-kernel@vger.kernel.org Subject: Re: [PATCH for 2.5] preemptible kernel In-Reply-To: Your message of "Wed, 21 Mar 2001 00:04:56 -0800." <3AB860A8.182A10C7@mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Wed, 21 Mar 2001 20:04:57 +1100 Message-ID: <22873.985165497@ocs3.ocs-net> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 21 Mar 2001 00:04:56 -0800, george anzinger wrote: >Exactly so. The method does not depend on the sum of preemption being >zip, but on each potential reader (writers take locks) passing thru a >"sync point". Your notion of waiting for each task to arrive >"naturally" at schedule() would work. It is, in fact, over kill as you >could also add arrival at sys call exit as a (the) "sync point". In >fact, for module unload, isn't this the real "sync point"? After all, a >module can call schedule, or did I miss a usage counter somewhere? A module can call schedule but it must do MOD_INC_USE_COUNT first. Sleeping in module code without incrementing the module use count first is a shooting offence. It is so full of races that you may as well call it Daytona. >By the way, there is a paper on this somewhere on the web. Anyone >remember where? http://www.rdrop.com/users/paulmck/paper/rclockpdcsproof.pdf - 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/