From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933127AbXCCWZo (ORCPT ); Sat, 3 Mar 2007 17:25:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933134AbXCCWZo (ORCPT ); Sat, 3 Mar 2007 17:25:44 -0500 Received: from mx1.redhat.com ([66.187.233.31]:60857 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933127AbXCCWZn (ORCPT ); Sat, 3 Mar 2007 17:25:43 -0500 Message-ID: <45E9F5DA.2070708@redhat.com> Date: Sat, 03 Mar 2007 17:25:30 -0500 From: Rik van Riel Organization: Red Hat, Inc User-Agent: Thunderbird 1.5.0.7 (X11/20061008) MIME-Version: 1.0 To: Andrew Morton CC: linux-kernel@vger.kernel.org Subject: Re: userspace pagecache management tool References: <20070303122935.f1ab0067.akpm@linux-foundation.org> <45E9DD4A.2060806@redhat.com> <20070303131204.6706a95c.akpm@linux-foundation.org> <45E9E910.2070804@redhat.com> <20070303140744.b22699dd.akpm@linux-foundation.org> In-Reply-To: <20070303140744.b22699dd.akpm@linux-foundation.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: > Well, backup programs are a unique case. Let's say instead that the user > has just generated a 600MB ISO image. > > The kernel *just doesn't know* whether the user will next try to read the > kernel tree or will next try to read that ISO image. > > That, Rik, is my point, and is the entire point of this work. I still don't understand why "the backup program flushed my data out of the cache with POSIX_FADV_DONTNEED" is an improvement over "the backup program flushed my data out of the cache by reading other files". Your code may be useful for a few specialized situations, but I don't see it actually fixing most of the examples you gave in your announcement, except for the DVD copying one. -- Politics is the struggle between those who want to make their country the best in the world, and those who believe it already is. Each group calls the other unpatriotic.