Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932444AbXARPXg (ORCPT ); Thu, 18 Jan 2007 10:23:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932445AbXARPXg (ORCPT ); Thu, 18 Jan 2007 10:23:36 -0500 Received: from caramon.arm.linux.org.uk ([217.147.92.249]:4400 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932444AbXARPXf (ORCPT ); Thu, 18 Jan 2007 10:23:35 -0500 Date: Thu, 18 Jan 2007 15:23:26 +0000 From: Russell King To: Tomas Carnecky Cc: Bernhard Walle , linux-kernel@vger.kernel.org, Alon Bar-Lev Subject: Re: [patch 03/26] Dynamic kernel command-line - arm Message-ID: <20070118152326.GC31418@flint.arm.linux.org.uk> Mail-Followup-To: Tomas Carnecky , Bernhard Walle , linux-kernel@vger.kernel.org, Alon Bar-Lev References: <20070118125849.441998000@strauss.suse.de> <20070118130028.719472000@strauss.suse.de> <20070118141359.GB31418@flint.arm.linux.org.uk> <45AF92E7.50901@dbservice.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <45AF92E7.50901@dbservice.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1361 Lines: 36 On Thu, Jan 18, 2007 at 04:31:51PM +0100, Tomas Carnecky wrote: > Russell King wrote: > > On Thu, Jan 18, 2007 at 01:58:52PM +0100, Bernhard Walle wrote: > >> -static char command_line[COMMAND_LINE_SIZE]; > >> +static char __initdata command_line[COMMAND_LINE_SIZE]; > > > > Uninitialised data is placed in the BSS. Adding __initdata to BSS > > data causes grief. > > > > Static variables are implicitly initialized to zero. Does that also > count as initialization? No. As I say, they're placed in the BSS. The BSS is zeroed as part of the C runtime initialisation. If you want to place a variable in a specific section, it must be explicitly initialised. Eg, static char __initdata command_line[COMMAND_LINE_SIZE] = ""; However, there is a bigger question here: that is the tradeoff between making this variable part of the on-disk kernel image, but throw away the memory at runtime, or to leave it in the BSS where it will not be part of the on-disk kernel image, but will not be thrown away at runtime. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/