From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH 7/8] readahead: basic support for backwards prefetching Date: Mon, 21 Nov 2011 15:33:09 -0800 Message-ID: <20111121153309.d2a410fb.akpm@linux-foundation.org> References: <20111121091819.394895091@intel.com> <20111121093846.887841399@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Linux Memory Management List , , Andi Kleen , Li Shaohua , LKML To: Wu Fengguang Return-path: In-Reply-To: <20111121093846.887841399@intel.com> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Mon, 21 Nov 2011 17:18:26 +0800 Wu Fengguang wrote: > Add the backwards prefetching feature. It's pretty simple if we don't > support async prefetching and interleaved reads. Well OK, but I wonder how many applications out there read files in reverse order. Is it common enough to bother special-casing in the kernel like this? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id C9C7E6B0069 for ; Mon, 21 Nov 2011 18:33:11 -0500 (EST) Date: Mon, 21 Nov 2011 15:33:09 -0800 From: Andrew Morton Subject: Re: [PATCH 7/8] readahead: basic support for backwards prefetching Message-Id: <20111121153309.d2a410fb.akpm@linux-foundation.org> In-Reply-To: <20111121093846.887841399@intel.com> References: <20111121091819.394895091@intel.com> <20111121093846.887841399@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Wu Fengguang Cc: Linux Memory Management List , linux-fsdevel@vger.kernel.org, Andi Kleen , Li Shaohua , LKML On Mon, 21 Nov 2011 17:18:26 +0800 Wu Fengguang wrote: > Add the backwards prefetching feature. It's pretty simple if we don't > support async prefetching and interleaved reads. Well OK, but I wonder how many applications out there read files in reverse order. Is it common enough to bother special-casing in the kernel like this? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755761Ab1KUXdP (ORCPT ); Mon, 21 Nov 2011 18:33:15 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:42959 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755585Ab1KUXdL (ORCPT ); Mon, 21 Nov 2011 18:33:11 -0500 Date: Mon, 21 Nov 2011 15:33:09 -0800 From: Andrew Morton To: Wu Fengguang Cc: Linux Memory Management List , , Andi Kleen , Li Shaohua , LKML Subject: Re: [PATCH 7/8] readahead: basic support for backwards prefetching Message-Id: <20111121153309.d2a410fb.akpm@linux-foundation.org> In-Reply-To: <20111121093846.887841399@intel.com> References: <20111121091819.394895091@intel.com> <20111121093846.887841399@intel.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 21 Nov 2011 17:18:26 +0800 Wu Fengguang wrote: > Add the backwards prefetching feature. It's pretty simple if we don't > support async prefetching and interleaved reads. Well OK, but I wonder how many applications out there read files in reverse order. Is it common enough to bother special-casing in the kernel like this?