Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751332AbWHJABY (ORCPT ); Wed, 9 Aug 2006 20:01:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751421AbWHJABY (ORCPT ); Wed, 9 Aug 2006 20:01:24 -0400 Received: from ms-smtp-01.nyroc.rr.com ([24.24.2.55]:39322 "EHLO ms-smtp-01.nyroc.rr.com") by vger.kernel.org with ESMTP id S1751332AbWHJABX (ORCPT ); Wed, 9 Aug 2006 20:01:23 -0400 Date: Wed, 9 Aug 2006 20:00:51 -0400 (EDT) From: Steven Rostedt X-X-Sender: rostedt@gandalf.stny.rr.com To: Esben Nielsen cc: Bill Huey , Robert Crocombe , linux-kernel@vger.kernel.org, Ingo Molnar , Thomas Gleixner , Darren Hart Subject: Re: [Patch] restore the RCU callback to defer put_task_struct() Re: Problems with 2.6.17-rt8 In-Reply-To: Message-ID: References: <1154541079.25723.8.camel@localhost.localdomain> <1154615261.32264.6.camel@localhost.localdomain> <20060808025615.GA20364@gnuppy.monkey.org> <20060808030524.GA20530@gnuppy.monkey.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1047 Lines: 27 On Thu, 10 Aug 2006, Esben Nielsen wrote: > > I had a long discussion with Paul McKenney about this. I opposed the patch > from a latency point of view: Suddenly a high-priority RT task could be > made into releasing a task_struct. It would be better for latencies to > defer it to a low priority task. > > The conclusion we ended up with was that it is not a job for the RCU > system, but it ought to be deferred to some other low priority task to > free the task_struct. > Fair enough. But by removing the rcu code to do the dirty work, we ended up breaking the code completely. So although the rcu work is not the right method, it needs to be there until we have a better solution. This solution is better than what is there right now in -rt8, and that is, -rt8 is broken without it! -- Steve - 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/