From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264085AbTFYBMe (ORCPT ); Tue, 24 Jun 2003 21:12:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263637AbTFYBKy (ORCPT ); Tue, 24 Jun 2003 21:10:54 -0400 Received: from mail-in-02.arcor-online.net ([151.189.21.42]:54184 "EHLO mail-in-02.arcor-online.net") by vger.kernel.org with ESMTP id S263462AbTFYBKl (ORCPT ); Tue, 24 Jun 2003 21:10:41 -0400 From: Daniel Phillips To: William Lee Irwin III Subject: Re: [RFC] My research agenda for 2.7 Date: Wed, 25 Jun 2003 03:25:47 +0200 User-Agent: KMail/1.5.2 Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <200306250111.01498.phillips@arcor.de> <200306250307.18291.phillips@arcor.de> <20030625011031.GP26348@holomorphy.com> In-Reply-To: <20030625011031.GP26348@holomorphy.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200306250325.47529.phillips@arcor.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 25 June 2003 03:10, William Lee Irwin III wrote: > On Wednesday 25 June 2003 02:47, William Lee Irwin III wrote: > >> Per struct address_space? This is an unnecessary limitation. > > On Wed, Jun 25, 2003 at 03:07:18AM +0200, Daniel Phillips wrote: > > It's a sensible limitation, it keeps the radix tree lookup simple. > > It severely limits its usefulness. Dropping in a more flexible data > structure should be fine. Eventually it could well make sense to do that, e.g., the radix tree eventually ought to evolve into a btree of extents (probably). But making things so complex in the first version, thus losing much of the incremental development advantage, would not be smart. With a single size of page per address_space, changes to the radix tree code are limited to a couple of lines, for example. But perhaps you'd like to supply some examples where more than one size of page in the same address space really matters? > On Wednesday 25 June 2003 02:47, William Lee Irwin III wrote: > >> This gives me the same data structure proliferation chills as bh's. > > On Wed, Jun 25, 2003 at 03:07:18AM +0200, Daniel Phillips wrote: > > It's not nearly as bad. There is no distinction between subpage and base > > struct page for almost all page operations, e.g., locking, IO, data > > access. > > But those are code sanitation issues. You need to make sure this > doesn't explode on PAE. Indeed, that is important. Good night, see you tomorrow. Daniel