Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753417AbZC0MGo (ORCPT ); Fri, 27 Mar 2009 08:06:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751175AbZC0MGf (ORCPT ); Fri, 27 Mar 2009 08:06:35 -0400 Received: from fornax.pixelized.ch ([88.198.8.169]:60460 "EHLO fornax.pixelized.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750996AbZC0MGf (ORCPT ); Fri, 27 Mar 2009 08:06:35 -0400 X-Greylist: delayed 378 seconds by postgrey-1.27 at vger.kernel.org; Fri, 27 Mar 2009 08:06:34 EDT Message-ID: <49CCBFC4.7070707@cateee.net> Date: Fri, 27 Mar 2009 13:00:04 +0100 From: "Giacomo A. Catenazzi" User-Agent: Thunderbird 2.0.0.21 (Windows/20090302) MIME-Version: 1.0 To: Alan Cox CC: Linus Torvalds , Theodore Tso , Ingo Molnar , Jan Kara , Andrew Morton , Arjan van de Ven , Peter Zijlstra , Nick Piggin , Jens Axboe , David Rees , Jesper Krogh , Linux Kernel Mailing List , Oleg Nesterov , Roland McGrath Subject: Re: ext3 IO latency measurements References: <20090325185824.GO32307@mit.edu> <20090325215137.GQ32307@mit.edu> <20090325235041.GA11024@duck.suse.cz> <20090326090630.GA9369@elte.hu> <20090326113705.GV32307@mit.edu> <20090326140312.GB14822@elte.hu> <20090326144707.GA6239@mit.edu> <20090326170714.GF6239@mit.edu> <20090326185900.166a1097@lxorguk.ukuu.org.uk> In-Reply-To: <20090326185900.166a1097@lxorguk.ukuu.org.uk> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1060 Lines: 34 Alan Cox wrote: >> And what's the argument for not doing it in the kernel? >> >> The fact is, "atime" by default is just wrong. > > It probably was a wrong default - twenty years ago. Actually it may well > have been a wrong default in Unix v6 8) > > However > - atime behaviour is SuS required so I propose an other mount option along to strictatime: nowatime: it give the actual time as atime: it is totally useless, but fast *and* POSIX compatible: - no disk writes on accesses - POSIX doesn't mandate the behaviour of other processes, so we simulate that fs are scanned at every fs-tick. - IMHO more programs break, but in this case only the POSIX incompatible programs. > - there are users with systems out there using atime and dependant on > proper atime This is the real problem. ciao cate -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/