From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Chinner Subject: Re: The VFS hot tracking debacle Date: Fri, 18 Jul 2014 07:52:48 +1000 Message-ID: <20140717215248.GD20518@dastard> References: <1383745544-391-1-git-send-email-zwu.kernel@gmail.com> <2831755.nuyKSN0E6B@merkaba> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Daniel Poelzleithner , linux-fsdevel@vger.kernel.org To: Martin Steigerwald Return-path: Received: from ipmail06.adl2.internode.on.net ([150.101.137.129]:23966 "EHLO ipmail06.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754216AbaGQVww (ORCPT ); Thu, 17 Jul 2014 17:52:52 -0400 Content-Disposition: inline In-Reply-To: <2831755.nuyKSN0E6B@merkaba> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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.... Cheers, Dave. -- Dave Chinner david@fromorbit.com