From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765815AbYA2UB1 (ORCPT ); Tue, 29 Jan 2008 15:01:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758929AbYA2UBC (ORCPT ); Tue, 29 Jan 2008 15:01:02 -0500 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:37024 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758375AbYA2UA7 (ORCPT ); Tue, 29 Jan 2008 15:00:59 -0500 Message-ID: <479F85F9.3040104@sgi.com> Date: Tue, 29 Jan 2008 12:00:57 -0800 From: Mike Travis User-Agent: Thunderbird 2.0.0.6 (X11/20070801) MIME-Version: 1.0 To: Ingo Molnar CC: Andrew Morton , Andi Kleen , Christoph Lameter , jeremy@goop.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] percpu: Optimize percpu accesses References: <20080123044924.508382000@sgi.com> <20080124224613.GA24855@elte.hu> In-Reply-To: <20080124224613.GA24855@elte.hu> 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 Ingo Molnar wrote: ... > > tried it on x86.git and 1/3 did not build and 2/3 causes a boot hang > with the attached .config. > > Ingo > I've tracked down the failure to an early printk that when CONFIG_PRINTK_TIME is enabled, any early printks cause cpu_clock to be called, which accesses cpu_rq which is defined as: 595 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) Since the zero-based patch is changing the offset from one based on __per_cpu_start to zero, it's causing the function to access a different area. I'm working on a fix now. Thanks, Mike