From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760266AbYDVQmc (ORCPT ); Tue, 22 Apr 2008 12:42:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754354AbYDVQmY (ORCPT ); Tue, 22 Apr 2008 12:42:24 -0400 Received: from relay1.sgi.com ([192.48.171.29]:57144 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753907AbYDVQmX (ORCPT ); Tue, 22 Apr 2008 12:42:23 -0400 Message-ID: <480E156D.4090100@sgi.com> Date: Tue, 22 Apr 2008 09:42:21 -0700 From: Mike Travis User-Agent: Thunderbird 2.0.0.6 (X11/20070801) MIME-Version: 1.0 To: Tony Luck CC: Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH 04/12] sched: Remove fixed NR_CPUS sized arrays in kernel_sched_c v2 References: <20080405011100.720014000@polaris-admin.engr.sgi.com> <20080405011101.534396000@polaris-admin.engr.sgi.com> <12c511ca0804220916i5c181202pecf8fee7153e54fc@mail.gmail.com> In-Reply-To: <12c511ca0804220916i5c181202pecf8fee7153e54fc@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Tony Luck wrote: > On Fri, Apr 4, 2008 at 6:11 PM, Mike Travis wrote: >> @@ -7297,6 +7287,11 @@ void __init sched_init_smp(void) >> #else >> void __init sched_init_smp(void) >> { >> +#if defined(CONFIG_NUMA) >> + sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **), >> + GFP_KERNEL); >> + BUG_ON(sched_group_nodes_bycpu == NULL); >> +#endif >> sched_init_granularity(); >> } >> #endif /* CONFIG_SMP */ > > This hunk is causing problems with one of my builds (generic, > uniprocessor). Note > that the #else at the start of this hunk is from a #ifdef CONFIG_SMP ... so I'm > wondering why we need #if defined(CONFIG_NUMA) inside uniprocessor code :-) > How can you have NUMA issues with only one cpu!!! > > [I'm also wondering why the config that has the compile problem has CONFIG_SMP=n > and CONFIG_NUMA=y ... but that weirdness exposed this silliness, so > perhaps it isn't > all bad] > > Error message is: > kernel/sched.c: In function `sched_init_smp': > kernel/sched.c:7994: error: `sched_group_nodes_bycpu' undeclared > (first use in this function) > kernel/sched.c:7994: error: (Each undeclared identifier is reported only once > kernel/sched.c:7994: error: for each function it appears in.) > > -Tony Hi Tony, Hmm, yes, good point. I guess you might have it when there's a single processor under a guest OS that's not on node 0, but I suspect there's plenty of other problems with that scenario. We could make CONFIG_NUMA dependent on CONFIG_SMP? Or define sched_group_nodes_bycpu for the non-SMP case? [I'll have to go back to that patch and research why I added this.] Thanks, Mike