Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 5 Oct 2001 08:50:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 5 Oct 2001 08:50:00 -0400 Received: from eventhorizon.antefacto.net ([193.120.245.3]:30091 "EHLO eventhorizon.antefacto.net") by vger.kernel.org with ESMTP id ; Fri, 5 Oct 2001 08:49:46 -0400 Message-ID: <3BBDAB24.7000909@antefacto.com> Date: Fri, 05 Oct 2001 13:44:20 +0100 From: Padraig Brady User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.4) Gecko/20010913 X-Accept-Language: en-us MIME-Version: 1.0 To: Andi Kleen CC: Alex Larsson , Ulrich Drepper , linux-kernel@vger.kernel.org Subject: Re: Finegrained a/c/mtime was Re: Directory notification problem In-Reply-To:

<20011003232609.A11804@gruyere.muc.suse.de> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andi Kleen wrote: >On Wed, Oct 03, 2001 at 11:15:04AM -0400, Alex Larsson wrote: > >>Is a nanoseconds field the right choice though? In reality you might not >>have a nanosecond resolution timer, so you would miss changes that appear >>on shorter timescale than the timer resolution. Wouldn't a generation >>counter, increased when ctime was updated, be a better solution? >> > >Near any CPU has a cycle counter builtin now, which gives you ns like >resolution. In theory you could still get collisions on MP systems, >but window is small enough that it can be ignored in practice. > >-Andi > But the point is you, only ever would want nano second resolution to make sure you notice all changes to a file. A more general (and much simpler) solution would be to gen_count++ every time a file's modified. What other applications would require better than second resolution on files? Padraig. - 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/