Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 5 Oct 2001 15:12:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 5 Oct 2001 15:12:10 -0400 Received: from ns.suse.de ([213.95.15.193]:15889 "HELO Cantor.suse.de") by vger.kernel.org with SMTP id ; Fri, 5 Oct 2001 15:12:08 -0400 Date: Fri, 5 Oct 2001 21:12:35 +0200 From: Andi Kleen To: Padraig Brady Cc: Andi Kleen , Alex Larsson , Ulrich Drepper , linux-kernel@vger.kernel.org Subject: Re: Finegrained a/c/mtime was Re: Directory notification problem Message-ID: <20011005211235.A16163@gruyere.muc.suse.de> In-Reply-To:

<20011003232609.A11804@gruyere.muc.suse.de> <3BBDAB24.7000909@antefacto.com> <20011005150144.A11810@gruyere.muc.suse.de> <3BBDB26D.2050705@antefacto.com> <20011005163807.A13524@gruyere.muc.suse.de> <3BBDCAF8.6070705@antefacto.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <3BBDCAF8.6070705@antefacto.com>; from padraig@antefacto.com on Fri, Oct 05, 2001 at 04:00:08PM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 05, 2001 at 04:00:08PM +0100, Padraig Brady wrote: > Andi Kleen wrote: > > >>>Another advantage of using the real time instead of a counter is that > >>>you can easily merge the both values into a single 64bit value and do > >>>arithmetic on it in user space. With a generation counter you would need > >>>to work with number pairs, which is much more complex. > >>> > >>?? > >>if (file->mtime != mtime || file->gen_count != gen_count) > >> file_changed=1; > >> > > > >And how would you implement "newer than" and "older than" with a generation > >count that doesn't reset in a always fixed time interval (=requiring > >additional timestamps in kernel)? > > > >-Andi > > > Well IMHO "newer than", "older than" applications have until now > done with second resolution, and that's all that's required? No they haven't. GNU make supports nsec mtime on Solaris and apparently some other OS too, because the second granuality mtime can be a big problem with make -j on a big SMP box. make has to distingush "is older" from "is newer"; "not equal" alone doesn't cut it. [If you think it is modify your make to replace the "is older" check for dependencies with "is not equal" and see what happens] -Andi - 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/