From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263996AbTDYVAl (ORCPT ); Fri, 25 Apr 2003 17:00:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263997AbTDYVAl (ORCPT ); Fri, 25 Apr 2003 17:00:41 -0400 Received: from neon-gw-l3.transmeta.com ([63.209.4.196]:11278 "EHLO neon-gw.transmeta.com") by vger.kernel.org with ESMTP id S263996AbTDYVAk (ORCPT ); Fri, 25 Apr 2003 17:00:40 -0400 Message-ID: <3EA9A4B8.2030304@zytor.com> Date: Fri, 25 Apr 2003 14:12:24 -0700 From: "H. Peter Anvin" Organization: Zytor Communications User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20030225 X-Accept-Language: en, sv MIME-Version: 1.0 To: "Martin J. Bligh" CC: linux-kernel@vger.kernel.org Subject: Re: TASK_UNMAPPED_BASE & stack location References: <459930000.1051302738@[10.10.2.4]> <1750000.1051305030@[10.10.2.4]> In-Reply-To: <1750000.1051305030@[10.10.2.4]> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Martin J. Bligh wrote: >>>Is there any good reason we can't remove TASK_UNMAPPED_BASE, and just >>>shove libraries directly above the program text? Red Hat seems to have >>>patches to dynamically tune it on a per-processes basis anyway ... >>> >>>Moreover, can we put the stack back where it's meant to be, below the >>>program text, in that wasted 128MB of virtual space? Who really wants >>> >>>>128MB of stack anyway (and can't fix their app)? >> >>That space is NULL pointer trap zone. NULL pointer trapping -> good. > > > 128Mb of it? The bottom page, or even a few Mb, sure ... > but 128Mb seems somewhat excessive ... > Perhaps, but large data structures can easily generate reasonably large values when indirected. -hpa