From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762642AbYBMNDY (ORCPT ); Wed, 13 Feb 2008 08:03:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752572AbYBMNDK (ORCPT ); Wed, 13 Feb 2008 08:03:10 -0500 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:51408 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1761606AbYBMNDJ (ORCPT ); Wed, 13 Feb 2008 08:03:09 -0500 Date: Wed, 13 Feb 2008 05:03:40 -0800 (PST) Message-Id: <20080213.050340.64342037.davem@davemloft.net> To: mingo@elte.hu Cc: rdreier@cisco.com, linux-kernel@vger.kernel.org Subject: Re: Strange hang on ia64 with CONFIG_PRINTK_TIME=y From: David Miller In-Reply-To: <20080213125725.GC6344@elte.hu> References: <20080212.230156.33759433.davem@davemloft.net> <20080213125725.GC6344@elte.hu> X-Mailer: Mew version 5.2 on Emacs 22.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ingo Molnar Date: Wed, 13 Feb 2008 13:57:25 +0100 > so .. how about the patch below? Note that we already had an "early > bootup" special (the rq->idle check), it's now just made explicit via > the scheduler_running flag. I don't see what the problem is. It is legal to access per-cpu data as early as you like, it just evaluates to the static copy in the per-cpu section of the kernel image until the per-cpu areas are setup. rq->idle should also be zero this early as well, that's also legal to rely upon I see nothing illegal in what cpu_clock() is doing, that's why I fixed the sparc64 per-cpu problem I ran into since sparc64 was doing the wrong thing when booted on a non-zero cpu.