From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763795AbZEHTP3 (ORCPT ); Fri, 8 May 2009 15:15:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754254AbZEHTPS (ORCPT ); Fri, 8 May 2009 15:15:18 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:54763 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753910AbZEHTPR (ORCPT ); Fri, 8 May 2009 15:15:17 -0400 Date: Fri, 8 May 2009 21:13:55 +0200 From: Ingo Molnar To: Jeff Garzik Cc: Peter Zijlstra , LKML , viro@zeniv.linux.org.uk, Andrew Morton , roland@redhat.com Subject: Re: [PATCH 1/2] kernel/{sched,smp}.c: fix static decl prior to struct declaration Message-ID: <20090508191355.GC12130@elte.hu> References: <20090508184838.GA11157@havoc.gtf.org> <20090508190409.GA12130@elte.hu> <4A04833B.1010209@garzik.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A04833B.1010209@garzik.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jeff Garzik wrote: > Ingo Molnar wrote: >> * Jeff Garzik wrote: >> >>> According to C99 6.9.2p3, any declaration "static struct foo my_foo;" >>> must follow the definition of struct foo. >>> >>> Apparently, gcc's lack of warning is a bug. >>> >>> Signed-off-by: Jeff Garzik >> >> good spotting, i'll apply this fix, but: >> >>> */ >>> struct task_group root_task_group; >>> -#ifdef CONFIG_FAIR_GROUP_SCHED >>> -/* Default task group's sched entity on each cpu */ >>> -static DEFINE_PER_CPU(struct sched_entity, init_sched_entity); >>> -/* Default task group's cfs_rq on each cpu */ >>> -static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp; >>> -#endif /* CONFIG_FAIR_GROUP_SCHED */ >>> - >>> -#ifdef CONFIG_RT_GROUP_SCHED >>> -static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity); >>> -static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp; >>> -#endif /* CONFIG_RT_GROUP_SCHED */ >>> -#else /* !CONFIG_USER_SCHED */ >>> -#define root_task_group init_task_group >>> -#endif /* CONFIG_USER_SCHED */ >>> - >>> /* task_group_lock serializes add/remove of task groups and also changes to >> >> This block has a visible imbalance of preprocessor directives - >> there's a #else you moved, without moving the outermost #ifdef. My >> guess is that this will go down in a fireball with CONFIG_GROUP_SCHED >> disabled? > > It seems you are correct, I missed it in my 'allmodconfig' and > 'jeffs hw config' builds. > > Are you fixing this up, or should I regen the patch? Please resend it. That area of the code is a bit of an #ifdef maze, hard to move around. (And i'd rather let you mess it up than mess it up myself - then i can blame it on you and bounce it back to you for fixing ;-) Also, a style cleanup there might help a bit: adding a bit more geometric structure to the #ifdefs there might make the hierarchy stand out a bit more: # ifdef CONFIG_RT_GROUP_SCHED static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity); static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp; # endif /* CONFIG_RT_GROUP_SCHED */ #else /* !CONFIG_USER_SCHED */ # define root_task_group init_task_group #endif /* CONFIG_USER_SCHED */ in such a lineup it's more apparent at a glance when a piece of code gets snatched in an incomplete way. Thanks, Ingo