From mboxrd@z Thu Jan 1 00:00:00 1970 From: Randy Dunlap Subject: Re: [PATCH] mm: add config NUMA stub to all architectures Date: Sun, 19 Feb 2012 10:12:29 -0800 Message-ID: <4F413B8D.5080307@xenotime.net> References: <4F3E42E0.4030108@openvz.org> <20120217120815.25909.15632.stgit@zurg> <20120217123037.ecfc5dd9.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kbuild-owner@vger.kernel.org To: Geert Uytterhoeven Cc: Andrew Morton , Konstantin Khlebnikov , Stephen Rothwell , linux-next@vger.kernel.org, LKML , Sam Ravnborg , Michal Marek , linux-kbuild@vger.kernel.org List-Id: linux-next.vger.kernel.org On 02/19/2012 09:01 AM, Geert Uytterhoeven wrote: > On Fri, Feb 17, 2012 at 21:30, Andrew Morton wrote: >> On Fri, 17 Feb 2012 16:08:15 +0400 >> Konstantin Khlebnikov wrote: >> >>> Config NUMA must be defined for all architectures, >>> otherwise IS_ENABLED(CONFIG_NUMA) does not work. >>> Some arch-specific Kconfig already has this stub. >>> This patch adds it to all remaining. >> >> It would be better to teach IS_ENABLED() to handle this situation. I >> don't think there's a way of doing this with cpp :( >> >> This limitation makes IS_ENABLED pretty dangerous, doesn't it? It >> makes it very easy to introduce build breakage with unexpected Kconfig >> combinations. > > Indeed. Recently I discovered IS_ENABLED() and started recommending it > to people for new code. But now I've seen the CONFIG_NUMA breakage, > I no longer think this is a good recommendation. adding Michal & linux-kbuild to cc: list. -- ~Randy