From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264639AbUE0O5n (ORCPT ); Thu, 27 May 2004 10:57:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264625AbUE0O5c (ORCPT ); Thu, 27 May 2004 10:57:32 -0400 Received: from fw.osdl.org ([65.172.181.6]:48327 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S264639AbUE0O4L (ORCPT ); Thu, 27 May 2004 10:56:11 -0400 Date: Thu, 27 May 2004 07:55:36 -0700 (PDT) From: Linus Torvalds To: Andrea Arcangeli cc: Brian Gerst , Ingo Molnar , =?iso-8859-1?Q?J=F6rn?= Engel , Arjan van de Ven , Rik van Riel , linux-kernel@vger.kernel.org Subject: Re: 4k stacks in 2.6 In-Reply-To: <20040527145033.GF3889@dualathlon.random> Message-ID: References: <20040525211522.GF29378@dualathlon.random> <20040526103303.GA7008@elte.hu> <20040526125014.GE12142@wohnheim.fh-wedel.de> <20040526125300.GA18028@devserv.devel.redhat.com> <20040526130047.GF12142@wohnheim.fh-wedel.de> <20040526130500.GB18028@devserv.devel.redhat.com> <20040526164129.GA31758@wohnheim.fh-wedel.de> <20040527124551.GA12194@elte.hu> <20040527135930.GC3889@dualathlon.random> <40B5F8C0.2010005@didntduck.org> <20040527145033.GF3889@dualathlon.random> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 27 May 2004, Andrea Arcangeli wrote: > > On Thu, May 27, 2004 at 10:18:40AM -0400, Brian Gerst wrote: > > The problem on i386 (unlike x86-64) is that the thread_info struct sits > > at the bottom of the stack and is referenced by masking bits off %esp. > > So the stack size must be constant whether in process context or IRQ > > context. > > so what, that's a minor implementation detail, pda is a software thing. "minor implementation detail"? You need to get to the thread info _some_ way, and you need to get to it _fast_. There are really no sane alternatives. I certainly do not want to play games with segments. Linus