From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Steigerwald Subject: Re: The VFS hot tracking debacle Date: Fri, 18 Jul 2014 10:25:23 +0200 Message-ID: <5288000.xmdEPgGx6M@merkaba> References: <1383745544-391-1-git-send-email-zwu.kernel@gmail.com> <2831755.nuyKSN0E6B@merkaba> <20140717215248.GD20518@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: Daniel Poelzleithner , linux-fsdevel@vger.kernel.org To: Dave Chinner Return-path: Received: from mondschein.lichtvoll.de ([194.150.191.11]:46966 "EHLO mail.lichtvoll.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754762AbaGRIZZ (ORCPT ); Fri, 18 Jul 2014 04:25:25 -0400 In-Reply-To: <20140717215248.GD20518@dastard> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Am Freitag, 18. Juli 2014, 07:52:48 schrieb Dave Chinner: > On Thu, Jul 17, 2014 at 11:34:49PM +0200, Martin Steigerwald wrote: > > Am Donnerstag, 17. Juli 2014, 19:35:53 schrieb Daniel Poelzleithner: > > > Zhi Yong Wu gmail.com> writes: > > > > Ping ^ 7 > > > > > > I'm following this patch now for quite some time and I have to say that > > > this thread+patch is one of the most disappointing experiences I had > > > with kernel development. > > > > > > I can't understand why such a patch is simply ignored from the > > > maintainers > > > of the subsystem, no comment, no review, no checkin. > > > > I always wanted to try this one out, but never got around doing it. > > > > I really like the general approach of it to put the general stuff into VFS > > and only the special stuff into filesystems like BTRFS. > > And that's the core issue here: there are no applications that use > the information. i.e. it's a solution looking for a problem. > > I spent a lot of time reviewing and helping on this, and I made > repeated suggestions that applications like xfs_fsr could make use > of the information to do optimised file layout during > defragmentation, but nothing like that has ever been implemented. > > So, really, until there is an application that actually demonstrates > the usefulness of the specific information that is tracked and > exported, we can't verify that the code as it stands is actually > useful. We can verify that the code doesn't have problems, but we > can't verify whether it is fit for purpose because it currently has > no purpose.... So this needs an example implementation for one filesystem? I thought there is one for BTRFS. Ciao, -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7