Patch(2.5.54): devfs shrink - integration candidate

Patch(2.5.54): devfs shrink - integration candidate

[Adam J. Richter]

 	The sixth iteration of my devfs code shink is available here:

ftp://ftp.yggdrasil.com/pub/dist/device_control/devfs/smalldevfs-2.5.54-v6.patch
	I believe the deletions make the patch so big that the
linux-kernel mailing list filters prevent me from submit an email that
includes it.

	This patch reduces include/linux/devfs*.h and fs/devfs from
3655 lines to 1239, a reduction of 2450 lines, nearly a factor three.
That may not be as impressive as the original 5X reduction, but that
is mostly because I've restored a bunch of functionality that I hope
to eliminate in the future.

	I'd like to thank Richard Gooch for writing devfs.  I think it
was a great idea and the effort involved in implementing it,
especially when it was not clear that it could work well, was probably
about 30-100 times my effort in shrinking it.  I immediately became a
convert within a day of trying it.  I'd be happy for Richard to take
over this code and continue maintaining devfs.  If he doesn't want to,
I'm willing to and I'm also happy to let someone else do it if they
want.

	This is nearly the same patch that I attempted to post on
January 2, but apparently some well intentioned spam filter blocked
it.  I had this problem once before, also when submitting a big patch
with a lot of deletions sent as a MIME attachment.  This time I'm
submitting the patch as part of the text of my message.

	The there are no code changes between this version and the one
that I tried to post on January 2.  In the meantime, I've used it and
stared at it more, and now I'm posting this as a candiate for
integration into Linus's kernel.

	The January 2 version introduced two significant changes:
isolating the filesystem driver to a separate file that only exports
two symbols (devfs_vfsmount and init_devfs_fs), and making that patch
a change to fs/devfs rather than a new filesystem.  (If anyone would
prefer that I submit this as a separate file system, please let me
know.)

        If you want devfsd functionality (well, at least the
"REGISTER" and "LOOKUP" events), you can get my user level program
devfs_helper, which is a reduced functionality replacement program for
devfsd from the following URL.

ftp://ftp.yggdrasil.com/pub/dist/device_control/devfs_helper/devfs_helper-0.1.tar.gz

	devfs_helper is program that is exec'ed on each event rather
than being a daemon that waits on events.  When the new module_param
code is further developed, I will default the devfs_helper to be
turned off until a user level program sets the name of the program.

	Finally, I'd like to move forward toward getting this into
Linus's kernel.  Any blessings, curses, requests for changes or advice
on the best way to proceed would be appreciated.

-- 
Adam J. Richter     __     ______________   575 Oroville Road
adam@yggdrasil.com     \ /                  Milpitas, California 95035
+1 408 309-6081         | g g d r a s i l   United States of America
                         "Free Software For The Rest Of Us."

Re: Patch(2.5.54): devfs shrink - integration candidate

[Andi Kleen]

"Adam J. Richter" <adam@yggdrasil.com> writes:
> 
> 	Finally, I'd like to move forward toward getting this into
> Linus's kernel.  Any blessings, curses, requests for changes or advice
> on the best way to proceed would be appreciated.

Me thinks you're two to three months too late for 2.5. This looks definitely not like
a good idea to merge in a feature/code freeze, when the main goal should be to
finally get 2.6 out. Submit it when 2.7 opens.

-Andi

Re: Patch(2.5.54): devfs shrink - integration candidate

[Andrew Walrond]

> Me thinks you're two to three months too late for 2.5. This looks definitely not like
> a good idea to merge in a feature/code freeze, when the main goal should be to
> finally get 2.6 out. Submit it when 2.7 opens
> 
> -Andi

This would be a shame as it's excellent work and really just an tidy up 
of existing code rather than a new feature?

Re: Patch(2.5.54): devfs shrink - integration candidate

[John Bradford]

> > Me thinks you're two to three months too late for 2.5. This looks
> > definitely not like a good idea to merge in a feature/code freeze,
> > when the main goal should be to finally get 2.6 out. Submit it
> > when 2.7 opens
> 
> This would be a shame as it's excellent work and really just an tidy up 
> of existing code rather than a new feature?

Especially as we are not in a code freeze yet.

John.

Re: Patch(2.5.54): devfs shrink - integration candidate

[Andrew Morton]

"Adam J. Richter" wrote:
> 
>         The sixth iteration of my devfs code shink is available here:
> 
> ftp://ftp.yggdrasil.com/pub/dist/device_control/devfs/smalldevfs-2.5.54-v6.patch

That diff removes fs/namei.c.

Re: Patch(2.5.54): devfs shrink - integration candidate

[H. Peter Anvin]

Followup to:  <20030105203725.A10808@adam.yggdrasil.com>
By author:    "Adam J. Richter" <adam@yggdrasil.com>
In newsgroup: linux.dev.kernel
> 
> 	This patch reduces include/linux/devfs*.h and fs/devfs from
> 3655 lines to 1239, a reduction of 2450 lines, nearly a factor three.
> That may not be as impressive as the original 5X reduction, but that
> is mostly because I've restored a bunch of functionality that I hope
> to eliminate in the future.
> 

Do we have any idea what the impact of this is on runtime data size?
I seem to remember devfs playing lots of tricks to reduce its working
set.  If this code size reduction ends up pinning large data
structures like dentries and inodes which wouldn't otherwise have been
pinned, this could be a significant lose.

	-hpa
-- 
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
http://www.zytor.com/~hpa/puzzle.txt	<amsp@zytor.com>

Re: Patch(2.5.54): devfs shrink - integration candidate

[Adam J. Richter]

Andrew Morton caught writes:
>That diff removes fs/namei.c.

	Grr.  Thanks for catching that.  I obviously botched the diff.
I've removed the old patch.  Here is a corrected version:

ftp://ftp.yggdrasil.com/pub/dist/device_control/devfs/smalldevfs-2.5.54-v7.patch
Adam J. Richter     __     ______________   575 Oroville Road
adam@yggdrasil.com     \ /                  Milpitas, California 95035
+1 408 309-6081         | g g d r a s i l   United States of America
                         "Free Software For The Rest Of Us."