From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754044AbXH2SAt (ORCPT ); Wed, 29 Aug 2007 14:00:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751045AbXH2SAn (ORCPT ); Wed, 29 Aug 2007 14:00:43 -0400 Received: from pasmtpa.tele.dk ([80.160.77.114]:50860 "EHLO pasmtpA.tele.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750747AbXH2SAm (ORCPT ); Wed, 29 Aug 2007 14:00:42 -0400 Date: Wed, 29 Aug 2007 20:01:58 +0200 From: Sam Ravnborg To: Hugh Dickins Cc: Roman Zippel , linux-kernel@vger.kernel.org, kbuild-devel@lists.sourceforge.net Subject: Re: CONFIG_HOTPLUG_CPU: kconfig bug? Message-ID: <20070829180158.GA7849@uranus.ravnborg.org> References: <20070827172654.GA21871@uranus.ravnborg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > > I've noticed an oddity with CONFIG_HOTPLUG_CPU in 2.6.23-rc: > > > make oldconfig seems to turn it on even when nothing wants it, > > > increasing kernel size by about 10k; but if you then edit the > > > line out of .config and make oldconfig again, it correctly > > > offers the choice and lets it be turned off after all. I have tried to track down what is happening here. The culprint is: config SUSPEND_SMP bool depends on SUSPEND_SMP_POSSIBLE && PM_SLEEP select HOTPLUG_CPU default y It seems that due to the fact that SUSPEND_SMP is default y then kconfig enforce the "select HOTPLUG_CPU". And this happens despite the fact that PM_SLEEP is 'n' (but SUSPEND_SMP_POSSIBLE is 'y'). It is somewhere in sym_calc_value() or one of the childs that suddenly causes the change. But I find it hard to follow this part of the logic in kconfig. Roman - can you help here with what is going on? Sam