From: Ingo Molnar <mingo@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Randy Dunlap <rdunlap@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
David Rientjes <rientjes@google.com>,
David Woodhouse <dwmw2@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Sasha Levin <levinsasha928@gmail.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Pekka Enberg <penberg@kernel.org>, Michal Marek <mmarek@suse.cz>,
Stephen Rothwell <sfr@canb.auug.org.au>
Subject: Re: kvmtool tree (Was: Re: [patch] config: fix make kvmconfig)
Date: Tue, 12 Feb 2013 10:52:49 +0100 [thread overview]
Message-ID: <20130212095249.GC20039@gmail.com> (raw)
In-Reply-To: <CA+55aFxpH2A5pTkeAt-bapN6Erac7SSEUhS9qaZ6jUhm_0EAtA@mail.gmail.com>
* Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Mon, Feb 11, 2013 at 9:58 AM, Ingo Molnar <mingo@kernel.org> wrote:
> >
> > So basically Pekka optimistically thought it's an eventual
> > 'tit for tat', a constant stream of benefits to the kernel,
> > in the hope of finding a home in the upstream kernel which
> > would further help both projects. The kernel wants to keep
> > the 'tit' only though.
>
> Ingo, stop this idiotic nonsense.
>
> You seem to think that "kvmtool is useful for kernel" is
> somehow relevant.
>
> IT IS TOTALLY IRRELEVANT.
Please stop misrepresenting my opinion. My argument continues to
be that it was useful to the kernel in significant part
*BECAUSE* tools/kvm/ was integrated into a kernel repository -
on the main developers' systems.
You seem to take it for granted that causality cannot possibly
go the way that these kernel enhancements came mainly because
the tool was integrated into a kernel repo and was developed
very consciously within a kernel repo, as a (foster-)sister
project.
Why are you making that assumption? It's totally debatable and
we, who experienced that development process first hand, are
fiercely debating it.
Check the list I gave (unmodified):
"- Pekka listed new virtio drivers that were done via tools/kvm.
- Pekka listed ARM KVM support which was written/prototyped
using tools/kvm.
- There's over a dozen bugfixes in your kernel which were found
via syscall fuzzing built into tools/kvm. (I can dig them all
out if you want.)
- There are several fixes in the kernel side KVM subsystem
itself that were unearthed via tools/kvm.
- I showed how it helped the kernel by creating user-space
lockdep: code used in more situations means more exposure,
more bugfixes and more contributors. (It also allowed
immediate lockdep coverage for all the user-space mutexes
that tools/perf/ itself uses.)"
All but the fourth item (KVM fixes) were benefits that arose
largely because the tool was integrated into a kernel repository
and the developers found it easy to work that way.
In at least 3 cases above I could describe the actual, specific
development process that involved a single code base, even
adding features to *BOTH* the tool and the kernel, in one work
flow.
The resulting patches were then rebased after the fact (mostly
by Pekka), to merge upstream separately while waiting for the
tool to prove itself for upstream - losing its origin,
motivation and its history.
Could it have been attempted separately? Yes, just like perf
could have been tried as a separate project - but that is not
how it happened, that is not how the development flow unfolded,
and that is not what motivated those enhancements.
Just because it _could_ have been done independently does not
change the plain fact that tools/kvm was immensely kernel
focused.
Yes, it was unsolicited, yes you objected early on and loud
enough, and the kernel did not ask for this integration to begin
with - so there's not a hint of obligation on your part
whatsoever, but that does not change development reality as it
happened. I refuse to accept the rewriting of history.
> "sparse" is useful for kernel development. "git" is useful for
> kernel development. "xterm" is useful for kernel development.
That argument is silly beyond belief. Read this list:
- tools/kvm
- sparse
- git
- xterm
- perf
Which two tools in this list:
- Use and focus on Linux specific system calls to provide Linux
specific functionality?
- Are never - and will conceivably never - run on any kernel
which is not extremely Linux compatible?
- Provide essential features that need serious, tool specific
kernel side support?
- Were used directly to create integrated features that add
features BOTH to the kernel and the tool, at once?
I know that this discussion is not about changing your mind
anymore - every further email probably does the opposite.
I would accept many other arguments from you:
- you feel uneasy about growing the kernel into any sort of
platform. I would disagree but it's a fair argument.
- you think kernel developers should not do user-space
development and there should be a 'chinese wall' of ignorance
and a project boundary or two between them. I would disagree
but it's a fair argument.
- you think Qemu is better and is the official kernel side KVM
tool, and even if it's not better, it's (much) more complete
and a schizm is bad. It's a fair argument that I'd somewhat
agree with.
- you feel that if a tool cannot survive in the harsh realities
of the sourceforge or github ghetto, succeeding in
establishing itself and then hurting generations of
users with inconsistent, uncoordinated tinkerware, no matter
how Linux kernel centric the tool is conceptually, then it
does not deserve to live at all. I would disagree but it
would be a fair argument.
- you feel the kernel should be fundamentally tool neutral,
even if the lack of coherence and elongated coordination is
hurting the kernel, tools, developers and users. I'd disagree
with that but it would be a fair argument.
but stop the "integration did not benefit the kernel" or
"integration did not benefit the tool" crap please, it's
insulting. Both claims are false even if you ignore the
tools/perf example that shows the possible.
Thanks,
Ingo
next prev parent reply other threads:[~2013-02-12 9:52 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-20 21:51 [PATCH] x86: Default to ARCH=x86 to avoid overriding CONFIG_64BIT David Woodhouse
2012-12-21 2:07 ` [tip:x86/build] x86: Default to ARCH= x86 " tip-bot for David Woodhouse
2012-12-26 6:32 ` David Rientjes
2012-12-26 8:43 ` David Woodhouse
2012-12-26 10:44 ` David Rientjes
2012-12-26 12:38 ` David Woodhouse
2012-12-26 22:00 ` David Rientjes
2012-12-26 22:19 ` David Woodhouse
2012-12-27 1:52 ` David Rientjes
2012-12-27 8:01 ` David Woodhouse
2012-12-26 22:30 ` Jesper Juhl
2012-12-26 23:07 ` David Woodhouse
2012-12-26 23:13 ` H. Peter Anvin
2012-12-26 23:32 ` [tip] config: Add 'make kvmconfig' David Woodhouse
2012-12-27 1:08 ` Randy Dunlap
2013-02-04 18:20 ` [patch] config: fix make kvmconfig David Rientjes
2013-02-04 18:44 ` Ingo Molnar
2013-02-04 18:57 ` David Rientjes
2013-02-04 19:11 ` Ingo Molnar
2013-02-04 19:14 ` Greg Kroah-Hartman
2013-02-04 19:13 ` Ingo Molnar
2013-02-06 18:25 ` Pekka Enberg
2013-02-06 20:12 ` David Rientjes
2013-02-06 20:45 ` Pekka Enberg
2013-02-06 21:02 ` kvmtool tree (Was: Re: [patch] config: fix make kvmconfig) Stephen Rothwell
2013-02-06 21:46 ` Ingo Molnar
2013-02-06 21:55 ` H. Peter Anvin
2013-02-07 21:44 ` Stephen Rothwell
2013-02-07 21:40 ` Stephen Rothwell
2013-02-08 14:55 ` Ingo Molnar
2013-02-08 21:14 ` Linus Torvalds
2013-02-08 23:57 ` Pekka Enberg
2013-02-09 0:45 ` Linus Torvalds
2013-02-09 10:01 ` Pekka Enberg
2013-02-09 18:07 ` Linus Torvalds
2013-02-09 19:39 ` Pekka Enberg
2013-02-09 19:57 ` Linus Torvalds
2013-02-09 21:06 ` Theodore Ts'o
2013-02-11 12:38 ` Ingo Molnar
2013-02-11 12:26 ` Ingo Molnar
2013-02-11 12:56 ` Ingo Molnar
2013-02-11 13:18 ` David Woodhouse
2013-02-11 13:58 ` Anca Emanuel
2013-02-11 16:34 ` Linus Torvalds
2013-02-11 17:34 ` H. Peter Anvin
2013-02-11 17:41 ` Ingo Molnar
2013-02-11 14:47 ` Pekka Enberg
2013-02-11 16:46 ` David Woodhouse
2013-02-11 17:26 ` Anca Emanuel
2013-02-11 16:32 ` Linus Torvalds
2013-02-11 17:28 ` Ingo Molnar
[not found] ` <CA+55aFx-0-qcYMqH2wnJJ7iAPhoEvD_EQ0xqVW3VGS3G9=_1_w@mail.gmail.com>
2013-02-11 17:58 ` Ingo Molnar
2013-02-11 23:32 ` Linus Torvalds
2013-02-12 9:52 ` Ingo Molnar [this message]
2013-02-13 8:23 ` Paolo Bonzini
2013-02-13 8:56 ` Pekka Enberg
2013-02-13 9:23 ` Ingo Molnar
2013-02-14 15:32 ` Anthony Liguori
2013-02-19 8:08 ` Ingo Molnar
2013-01-12 17:06 ` [tip:x86/build] x86: Default to ARCH= x86 to avoid overriding CONFIG_64BIT Borislav Petkov
2013-01-12 17:40 ` H. Peter Anvin
2013-01-12 18:08 ` Borislav Petkov
2013-01-12 18:10 ` H. Peter Anvin
2013-04-12 16:01 ` [PATCH] x86: Default to ARCH=x86 " richard -rw- weinberger
2013-04-12 16:38 ` David Woodhouse
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