Re: Development tree, PLEASE?

[Marc Koschewski]

* Michael Loftis <mloftis@xxxxxxxxx> [2006-01-20 09:07:16 -0700]:

> 
> 
> --On January 20, 2006 4:59:19 PM +0100 Marc Koschewski 
> <marc@xxxxxxxxxxxxxxx> wrote:
> 
> >For my daily work I use the -git kernels on my production machines. And I
> >didn't have probs for a long time due to stuff being tested in -mm. -mm
> >is mostly broken for me (psmouse, now reiserfs, ...) but I tend to say
> >that 2.6 is rock-stable.
> >
> >When it comes to API stability people are encouraged to stay up-to-date
> >when when developing stuff out of the kernel tree, ain't they? A more
> >convenient way would be to create a new in-kernel-tree wrapper module
> >that wraps some functions no longer available anymore and which are
> >possible to be wrapped in the meaning of all needed data is provided to
> >the 'old' method and can be easyily wrapped into the new function.
> >
> >It could a Kconfig option so that the 'wrapper module' is only activated
> >on demand. Thus, having the option to port driver directly to the new API
> >or just silenty use the 'wrapper module' to translate the call while
> >being noisy at compile time.
> >
> >You're free to write the module... ;)
> 
> I know this, but the in-kernel stuff is far less painful than when all this 
> stuff bleeds to userland.  Besides, can you imagine such a beast of a 
> module? :D  I mean yeouch, the maintenance.  And it'd encourage the sort of 
> thing we as kernel developers in general want to discourage, which is the 
> use of deprecated APIs.

I know. But you we're the one who started this off. The 'beast' should be
maintained by people that need it. And it was just a brainstorm, moreover.

> 
> Lots of things still out there depend on devfs.  So now if I want to 
> develop my kmod on recent kernels I have to be in the business of 
> maintaining a lot more userland stuff, like mkinitrd, installers, etc. that 
> have come to rely on devfs.

What exactly relies on _devfs_?

> 
> The point is this is happening in what is being called a stable kernel. 
> Stable it isn't.  The whole devfs thing is likely to cause me a lot of 
> work, I'd stay with 2.4 in the worst affected things, but I can't.  devfs 
> is newish for and already been deprecated and killed before a major release 
> even, that just seems not right.

As far as I remember the devfs maintainer didn't do just a one-liner of changes
plus he was not to be reached by mail. No reply, no list acitivity, ... nothing.
Just out of the town.

> 
> Anyway hopefully this thread wills tart some constructive thought on this 
> rather than being pointless, but I had to get it out there.  I know I have 
> a habit of showing up every other year or so. :)

This thread will start something, yes. But I don't think we will have a decision
in the end. The kernel grows. In size, in features, in just about anything. And
from a developers point of view it's always wise to re-write a subsystem with a
new API and the freedom to do _whatever_ one thinks she could do than re-write a
subsystem due to maintaining the interface for compatibility.

The two cases exactly are:

	* _new_ code with all new features planned

	or

	* _partly new_ code with some new features due to API incompatibility a la
	  'what we have to do is to get the best we can from what we have'

And the latter is definitely the wrong way to go. Just my 2 cents...

Marc
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