Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759137AbXELVnP (ORCPT ); Sat, 12 May 2007 17:43:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754888AbXELVnD (ORCPT ); Sat, 12 May 2007 17:43:03 -0400 Received: from mail.screens.ru ([213.234.233.54]:51212 "EHLO mail.screens.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754797AbXELVnC (ORCPT ); Sat, 12 May 2007 17:43:02 -0400 Date: Sun, 13 May 2007 01:42:57 +0400 From: Oleg Nesterov To: Andi Kleen Cc: Andrew Morton , Christoph Lameter , Peter Zijlstra , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Ingo Molnar , Thomas Gleixner , Nick Piggin Subject: Re: [PATCH 1/2] scalable rw_mutex Message-ID: <20070512214257.GA389@tv-sign.ru> References: <20070511131541.992688403@chello.nl> <20070511132321.895740140@chello.nl> <20070511093108.495feb70.akpm@linux-foundation.org> <20070511110522.ed459635.akpm@linux-foundation.org> <20070512181254.GA331@tv-sign.ru> <20070512192130.GA8833@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070512192130.GA8833@one.firstfloor.org> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 994 Lines: 28 On 05/12, Andi Kleen wrote: > > > This also allows us to de-uglify workqueue.c a little bit, it uses > > a home-grown cpu_populated_map. > > It might be obsolete iff more and more architecture don't use NR_CPUS filled > possible_map anymore (haven't checked them all to know if it's true or not) > > If not there are a couple of more optimizations that can be done, e.g. > in networking by converting more code to hotplug notifier. As for workqueue.c, it is not an optimization. It is a documentation. For example, if CPU-hotplug use freezer, we can just do s/cpu_populated_map/cpu_online_map/ workqueue.c has a hotplug notifier, but we can't migrate work_structs currently in a race-free manner. So I vote for your patch in any case. Oleg. - 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/