linux-kernel - Re: [PATCH 2/8] um: Do not use SUBARCH

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Message-ID: <52442108.1020304@nod.at>
Date:	Thu, 26 Sep 2013 13:56:56 +0200
From:	Richard Weinberger <richard@....at>
To:	Ramkumar Ramachandra <artagnon@...il.com>
CC:	linux-arch@...r.kernel.org, Michal Marek <mmarek@...e.cz>,
	geert@...ux-m68k.org, ralf@...ux-mips.org, lethal@...ux-sh.org,
	Jeff Dike <jdike@...toit.com>,
	Guan Xuetao <gxt@...c.pku.edu.cn>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	linux-kbuild@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
	linux-m68k@...ts.linux-m68k.org, linux-mips@...ux-mips.org,
	linux-sh@...r.kernel.org,
	user-mode-linux-devel@...ts.sourceforge.net
Subject: Re: [PATCH 2/8] um: Do not use SUBARCH

Am 26.09.2013 13:43, schrieb Ramkumar Ramachandra:
> Richard Weinberger wrote:
>>> Auto-detection of SUBARCH, which can be done with a simple call to
>>> uname -m (the 90% case). The second patch I submitted prevented
>>> spawning xterms unnecessarily, which we discussed was a good move.
>>
>> Covering only 90% of all cases is not enough.
>> We must not break existing setups.
>> That's also why my "Get rid of SUBARCH" series is not upstream.
> 
> Mine covers 100% of the cases. My series is about auto-detection of
> SUBARCH, not its removal: you can still set a SUBARCH from the
> command-line; existing setups don't break.

I told you already that "make defconfig ARCH=um SUBARCH=x86" will spuriously
create a x86_64 config on x86_64.
This breaks existing setups.

>> Your second patch changed CONFIG_CON_CHAN to pts, which is ok but not
>> a major issue.
> 
> "Major" or "minor" is purely your classification: don't impose your
> value judgement on reasonable patches. I am the user, and I demand a
> pleasant build process and ui. Moreover, how do you expect more
> contributions to come in until existing patches make it to upstream?
> 
>> The xterms are also not spawning unnecessarily they spawn upon a tty device is opened.
>> With your patch UML create another pts. Thus, the spawning is hidden...
> 
> It connects to an existing host pts device instead of spawning a new
> xterm and connecting to the console io on that. Why is that not
> desirable?
> 
>> I did not push it upstream because it depended on your first one and as I said, it's not critical.
>> This does not mean that I moved it to /dev/null.
> 
> ... and you still haven't told me what's wrong with my first patch.
> 
>> Again, the plan is to get rid of SUBARCH at all.
> 
> You've been harping about this plan for the last N months, and nothing
> has happened so far. It's time to stop planning, and accept good work.

I sent the series on Aug 21st.
Do the maths, it's not N months...

>>>> make defconfig ARCH=um SUBARCH=x86 (or SUBARCH=i386) will create a defconfig for 32bit.
>>>> make defconfig ARCH=um SUBARCH=x86_64 one for 64bit.
>>>
>>> Yes, that's how I prepared the patch in the first place.
>>
>> So, nothing is broken.
> 
> So the user is Ugly and Stupid for expecting:
> 
>   $ "
>   $ make -j 8 ARCH=um
> 
> to work? Stop denying problems, no matter how "major" or "minor" they are.

"make defconfig ARCH=um" creates a defconfig for x86 as it always did.
If you want to run a x86_64 bit user space, create a x86_64 defconfig.

>> If you want "make defconfig ARCH=um" creating a defconfig for the correct arch you need
>> more than your first patch.
> 
> No, you don't. Try it for yourself and see. Set a SUBARCH if you like,
> and it'll still work fine.
> 
>> Again, "Get rid of SUBARCH" series has the same goal.
> 
> For the last time, getting rid of SUBARCH is Wrong and Undesirable.

That's your opinion.

> -- 8< --
> Here's a transcript spoonfeeding you the impact of my first patch:
> 
>   $ make defconfig ARCH=um SUBARCH=i386
>   *** Default configuration is based on 'i386_defconfig'
>   #
>   # configuration written to .config
>   #
>   $ make defconfig ARCH=um SUBARCH=x86_64
>   *** Default configuration is based on 'x86_64_defconfig'
>   #
>   # configuration written to .config
>   #
>   $ make defconfig ARCH=um
>   *** Default configuration is based on 'x86_64_defconfig'
>   #
>   # configuration written to .config
>   #
> 
> In the last case, notice how defconfig automatically picks up
> x86_64_defconfig correctly: if I were on an i386 machine, it would
> have picked up i386_defconfig like in the first case. Without my
> patch, the last case would have incorrectly picked up an i386
> defconfig, which is Stupid and Wrong.

You missed SUBARCH=x86.

That said, if you cover all cases I'll happily merge that.
And honestly, your patches are minor stuff, they don't even touch C source files.
Acting up like you do just because of some default values is crazy.
We have more serious problems so solve.

Thanks,
//richard
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