Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760502AbZCZTA1 (ORCPT ); Thu, 26 Mar 2009 15:00:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758411AbZCZTAG (ORCPT ); Thu, 26 Mar 2009 15:00:06 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:40850 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758859AbZCZTAF (ORCPT ); Thu, 26 Mar 2009 15:00:05 -0400 Date: Thu, 26 Mar 2009 18:59:00 +0000 From: Alan Cox To: Linus Torvalds Cc: 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 (was: Linux 2.6.29) Message-ID: <20090326185900.166a1097@lxorguk.ukuu.org.uk> In-Reply-To: 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> X-Mailer: Claws Mail 3.7.0 (GTK+ 2.14.7; x86_64-redhat-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 Content-Length: 975 Lines: 25 > 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 - there are users with systems out there using atime and dependant on proper atime So we can't change the ABI on them any more than we can decide that next week write() should return short values on writes to disk interrupted by signals... Letting distros flip to relatime means new installs and gradual migration occurs and nobody gets spectacularly blown up when their archiving system, their usage profiling and disk balancing tools and the like go wrong. -- 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/