Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756568AbZFVRIi (ORCPT ); Mon, 22 Jun 2009 13:08:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752335AbZFVRIb (ORCPT ); Mon, 22 Jun 2009 13:08:31 -0400 Received: from e1.ny.us.ibm.com ([32.97.182.141]:49430 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751299AbZFVRIa (ORCPT ); Mon, 22 Jun 2009 13:08:30 -0400 Date: Mon, 22 Jun 2009 10:08:31 -0700 From: "Paul E. McKenney" To: Darren Hart Cc: Andrew Morton , Ingo Molnar , David Howells , linux-kernel@vger.kernel.org, niv@us.ibm.com, lethal@linux-sh.org, kernel@wantstofly.org, matthew@wil.cx Subject: Re: [PATCH] v4 RCU: the bloatwatch edition Message-ID: <20090622170831.GF6754@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20090506112459.5edd0902.akpm@linux-foundation.org> <20090502163423.GA1633@linux.vnet.ibm.com> <12234.1241558327@redhat.com> <20090506120909.GR25203@elte.hu> <11979.1241648574@redhat.com> <26931.1245670998@redhat.com> <20090622124951.GB30553@elte.hu> <20090622082941.c5c8b3f3.akpm@linux-foundation.org> <20090622160753.GE6754@linux.vnet.ibm.com> <4A3FB1A5.3060805@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A3FB1A5.3060805@us.ibm.com> User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2348 Lines: 48 On Mon, Jun 22, 2009 at 09:30:29AM -0700, Darren Hart wrote: > Paul E. McKenney wrote: >> On Mon, Jun 22, 2009 at 08:29:41AM -0700, Andrew Morton wrote: >>> On Mon, 22 Jun 2009 14:49:51 +0200 Ingo Molnar wrote: >>> >>>> * David Howells wrote: >>>> >>>>> Hi Paul, >>>>> >>>>> Are you going to push your RCU patch for this merge window? >>>> Andrew needs to be convinced for that to happen. >>>> >>> whome? I rarely have firm opinions on anything. iirc the question >>> here was "is it worth adding another RCU implementation to save 900 >>> bytes"? >>> >>> I find it pretty hard to see how to come up with "yes" for that one but >>> it's hardly a huge issue. If you guys feel otherwise then go wild. >> Well, I do need to pull the "expedited" interface into the bloatwatch >> version, and my update of rcutorture made me realize that I can cut >> out a few more bytes, so I will submit an update. For what it is worth, >> here are the opinions expressed on LKML: >> + Ingo Molnar: good documentation, minimal RCU implementation. >> ? Andi Kleen: will there be !SMP systems in the future? >> + Lennert Buytenhek: there will be !SMP ARM for a long time. >> + Paul Mundt: good idea for more-constrained SH platforms. >> + David Howells: Acked-by. works on FRV board. >> ? Andrew Morton: do we really need another RCU implementation? >> Of course, I well remember programming systems with 4K of core memory >> back in the 1970s, and therefore feel a bit guilty about sticking deep >> embedded platforms with the increase in memory footprint represented >> by Hierarchical RCU compared to Classic RCU. And Bloatwatch RCU is much >> smaller and easier to understand/maintain than is Classic RCU. >> So, again, I will forward port, optimize, test, and resubmit. > > IIRC, in previous threads on this topic, the Bloatwatch edition was > expected to replace Classic RCU. If so, wouldn't that address Andrew's > concern of "adding" another implementation? Andrew expressed a preference for dropping Classic RCU without adding Bloatwatch RCU. ;-) Thanx, Paul -- 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/