From: Dave Chinner <david@fromorbit.com>
To: Martin Steigerwald <Martin@lichtvoll.de>
Cc: Daniel Poelzleithner <gmane@poelzi.org>, linux-fsdevel@vger.kernel.org
Subject: Re: The VFS hot tracking debacle
Date: Sun, 20 Jul 2014 10:02:28 +1000 [thread overview]
Message-ID: <20140720000228.GK4453@dastard> (raw)
In-Reply-To: <5288000.xmdEPgGx6M@merkaba>
On Fri, Jul 18, 2014 at 10:25:23AM +0200, Martin Steigerwald wrote:
> 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 <zwu.kernel <at> 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.
The tracking of the "hot data" was implemented for both btrfs and
XFS. There isn't a *consumer* of that data, however, and that's the
missing piece of the picture.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2014-07-20 0:02 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-06 13:45 [PATCH v6 00/11] VFS hot tracking Zhi Yong Wu
2013-11-06 13:45 ` [PATCH v6 01/11] VFS hot tracking: Define basic data structures and functions Zhi Yong Wu
2013-11-06 13:45 ` [PATCH v6 02/11] VFS hot tracking: Track IO and record heat information Zhi Yong Wu
2013-11-06 13:45 ` [PATCH v6 03/11] VFS hot tracking: Add a workqueue to move items between hot maps Zhi Yong Wu
2013-11-06 13:45 ` [PATCH v6 04/11] VFS hot tracking: Add shrinker functionality to curtail memory usage Zhi Yong Wu
2013-11-06 13:45 ` [PATCH v6 05/11] VFS hot tracking: Add an ioctl to get hot tracking information Zhi Yong Wu
2013-11-06 13:45 ` [PATCH v6 06/11] VFS hot tracking: Add a /proc interface to make the interval tunable Zhi Yong Wu
2013-11-06 13:45 ` [PATCH v6 07/11] VFS hot tracking: Add a /proc interface to control memory usage Zhi Yong Wu
2013-11-11 22:15 ` Dave Hansen
2013-11-11 22:45 ` Zhi Yong Wu
2013-11-12 17:05 ` Dave Hansen
2013-11-12 20:38 ` Zhi Yong Wu
2013-11-12 21:02 ` Dave Hansen
2013-11-12 21:56 ` Zhi Yong Wu
2013-12-11 15:44 ` Zhi Yong Wu
2013-11-06 13:45 ` [PATCH v6 08/11] VFS hot tracking: Add documentation Zhi Yong Wu
2013-11-06 13:45 ` [PATCH v6 09/11] VFS hot tracking, btrfs: Add hot tracking support Zhi Yong Wu
2013-11-06 13:45 ` [PATCH v6 10/11] VFS hot tracking, xfs: " Zhi Yong Wu
2013-11-06 13:45 ` [PATCH v6 11/11] MAINTAINERS: add the maintainers for VFS hot tracking Zhi Yong Wu
2013-11-11 15:43 ` [PATCH v6 00/11] " Zhi Yong Wu
2013-11-13 18:33 ` Zhi Yong Wu
2013-11-21 13:57 ` Zhi Yong Wu
2013-11-30 9:55 ` Zhi Yong Wu
2013-12-03 20:16 ` Zhi Yong Wu
2013-12-11 15:45 ` Zhi Yong Wu
2014-07-17 19:35 ` The VFS hot tracking debacle Daniel Poelzleithner
2014-07-17 21:34 ` Martin Steigerwald
2014-07-17 21:52 ` Dave Chinner
2014-07-18 8:25 ` Martin Steigerwald
2014-07-20 0:02 ` Dave Chinner [this message]
2014-07-25 8:43 ` Steven Whitehouse
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