From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S940398AbXGTQDR (ORCPT ); Fri, 20 Jul 2007 12:03:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932355AbXGTQDB (ORCPT ); Fri, 20 Jul 2007 12:03:01 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:44140 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934489AbXGTQC6 (ORCPT ); Fri, 20 Jul 2007 12:02:58 -0400 Date: Fri, 20 Jul 2007 09:02:32 -0700 (PDT) From: Linus Torvalds To: Fengguang Wu cc: Andi Kleen , Andrew Morton , linux-kernel Subject: Re: [PATCH 1/6] compacting file_ra_state In-Reply-To: <384933499.09699@ustc.edu.cn> Message-ID: References: <20070720100740.106917381@mail.ustc.edu.cn> <384926279.42287@ustc.edu.cn> <384933499.09699@ustc.edu.cn> 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 Fri, 20 Jul 2007, Fengguang Wu wrote: > On Fri, Jul 20, 2007 at 01:34:42PM +0200, Andi Kleen wrote: > > > > This would add a new limit to 64bit architectures. Surely keeping > > start at pgoff_t will not be a big issue? The other fields can be > > 32bit. > > Yeah, it counts for about 4MB memory for 1M opened files. I'd suggest keeping "start" as pgoff_t, and doing what Peter Zijlstra suggested about prev_offset / prev_index and turning that combination into a "loff_t". The latter will cause some more 64-bit operations, but by now I think we can start thinking of 64 bits as the norm, and it will be more logical, methinks. Then, when/if we add a config option to turn pgoff_t into a 32-bit entry for us normal people who think that 16TB is plenty (and would rather have smaller and faster harddisks than go beyond it), that will also solve the "start" issue. Does that sound like a plan? So I'm going to ignore the current series in the hopes that we'll have a new one soon enough. Linus