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From: James Bottomley <James.Bottomley@HansenPartnership•com>
To: Ingo Molnar <mingo@elte•hu>
Cc: Linus Torvalds <torvalds@linux-foundation•org>,
	Alan Cox <alan@lxorguk•ukuu.org.uk>,
	Thomas Gleixner <tglx@linutronix•de>,
	"H. Peter Anvin" <hpa@zytor•com>,
	Andrew Morton <akpm@linux-foundation•org>,
	Stephen Rothwell <sfr@canb•auug.org.au>,
	linux-next@vger•kernel.org
Subject: Re: Request for linux-next inclusion of the voyager tree
Date: Wed, 10 Jun 2009 14:23:31 +0000	[thread overview]
Message-ID: <1244643811.4109.13.camel@mulgrave.site> (raw)
In-Reply-To: <20090610003055.GA26492@elte.hu>

On Wed, 2009-06-10 at 02:30 +0200, Ingo Molnar wrote:
> * Linus Torvalds <torvalds@linux-foundation•org> wrote:
> 
> > On Wed, 10 Jun 2009, Ingo Molnar wrote:
> > 
> > > 
> > > * Alan Cox <alan@lxorguk•ukuu.org.uk> wrote:
> > > 
> > > > > This code has been NAK-ed by the x86 maintainers:
> > > > > 
> > > > >  - Due to the absurd irrelevance of Voyager/x86/Linux hardware
> > > > > 
> > > > >  - Due to the thousands of lines of of code it adds to arch/x86
> > > > >    to support a 486/P5 era piece of hardware
> > > > > 
> > > > >  - and due to its negative track record of:
> > > > > 
> > > > >     v2.6.27.0:   Voyager was broken - it did not even build. (!)
> > > > >     v2.6.28.0:   Voyager was broken - it did not even build. (!)
> > > > >     v2.6.29-rc5: Voyager was broken - it did not even build. (!)
> > > > 
> > > > So Ingo you are arguing "It didn't work in some releases so we 
> > > > want to make it continue not to work by trying to keep the fixes 
> > > > out" ?
> > > 
> > > No. This code is not in Linux right now, and that i see no reason to 
> > > put it back, for the (many) reasons outlined.
> > 
> > Ingo, "absurd irrelevance" is not a reason. If it was, we'd lose 
> > about half our filesystems etc.
> > 
> > Neither is "thousands of lines of code", or "it hasn't always 
> > worked". Again, if it was, then we'd have to get rid of just about 
> > all drivers out there.
> > 
> > So give some real reasons. "It's a maintenance nightmare because 
> > it does xyz" might be a reason. But then we really need to see the 
> > "xyz" part too.
> > 
> > Alan is definitely right that we're likely to see more of the 
> > "non-PC" platforms as x86 tries to do embedded.
> 
> That is true, and the whole painful conversion from the build-time 
> 32-bit sub-arch code to the unified runtime quirk code (which is 
> really 'non-PC platform driver' kind of thing) that i did a few 
> months ago was partly about that.
> 
> I dont dispute that aspect - in fact we merged a rare subarch as 
> well.
> 
> But Voyager has been the most painful subarchitecture by far - for 
> an extended period of time the code didnt even build in its 
> defconfig - and it is also the most useless one as well. So it was 
> just a token really.
> 
> The only action i got from James was when _I_ implemented the 
> proper, runtime subarch mechanism and when we actually _removed_ the 
> voyager code. Before it James resisted such changes, see this thread 
> almost a year ago, in the Nth "voyager breaks the build" discussion, 
> where i suggested:
> 
>   " btw., any chance to turn it into a quirk space thing? "
> 
>   http://lkml.org/lkml/2008/4/21/441
> 
> I got no action from James for my technical requests.

However, you did get a reply worrying about the technical aspects:

http://marc.info/?l=linux-kernel&m=120881937304045

And later on me worrying about the increase in pointer function
indirections.  When you forcibly did the conversion anyway the voyager
conversion was done within a couple of weeks.

>  Right now i 
> dont see any guarantee that this wont be repeated, once the code is 
> upstream again after meeting some threshold minimally.
> 
> Voyager was a painful experience to all x86 maintainers and i'd 
> expect pushers and supporters of rarely used code to do such work, 
> not maintainers.
> 
> Are the quality thresholds i outlined in the previous thread(s) 
> unreasonable? They were:
> 
>  " If the code is absolutely trouble-free out of tree, for an
>    equivalent amount of time (3 kernel releases or so), and gathers
>    users/testers/etc., then we might add it, after a thorough
>    technical review. "
> 
>   http://lkml.org/lkml/2009/4/19/181
> 
> Given that there are only two known boxes left (both James's, the 
> other one went missing in action somewhere in Brasil), the 'gather 
> testers' bit is unreasonable i guess. 'Prove you can stay trouble 
> free' is more realistic. Dunno.
> 
> See for example what happened in linux-next today: Voyager broke x86 
> and didnt even build, and Stephen had to keep it out of today's 
> linux-next build.

Integration testing in configurations I either can't build or don't have
the machine power to run over is one of the incredible values of
linux-next, and why stuff needs to be in there before being pulled into
mainline.  The bug was fixed within about an hour of being found, but I
need linux-next to help me find this and other problems.

James

  parent reply	other threads:[~2009-06-10 14:23 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-08 16:10 Request for linux-next inclusion of the voyager tree James Bottomley
2009-06-08 23:28 ` Tony Breeds
2009-06-10 14:45   ` James Bottomley
2009-06-09  9:45 ` Stephen Rothwell
2009-06-09 13:49   ` James Bottomley
2009-06-09 20:21 ` Ingo Molnar
2009-06-09 20:33   ` James Bottomley
2009-06-09 21:18     ` Ingo Molnar
2009-06-09 23:41   ` Alan Cox
2009-06-09 23:56     ` Ingo Molnar
2009-06-10  0:04       ` Linus Torvalds
2009-06-10  0:30         ` Ingo Molnar
2009-06-10  1:00           ` Ingo Molnar
2009-06-10 14:38             ` James Bottomley
2009-06-10 15:20               ` Linus Torvalds
2009-06-10 15:28                 ` James Bottomley
2009-06-10 15:33                   ` Linus Torvalds
2009-06-10 16:19                   ` Ingo Molnar
2009-06-10 16:42               ` Ingo Molnar
2009-06-10 14:23           ` James Bottomley [this message]
2009-06-10 15:13         ` Thomas Gleixner
2009-06-10 15:23           ` Linus Torvalds
2009-06-10 15:39             ` Ingo Molnar
2009-06-10 16:02               ` James Bottomley
2009-06-10 16:53                 ` Ingo Molnar
2009-06-11  1:35                   ` Stephen Rothwell
2009-06-11  1:39                     ` James Bottomley

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