Re: [GIT PULL] kdbus for 4.1-rc1

Richard Weinberger
2015-04-15T09:01:06Z

Am 15.04.2015 um 10:48 schrieb Greg Kroah-Hartman:
> On Wed, Apr 15, 2015 at 08:54:07AM +0200, Richard Weinberger wrote:
>> On Wed, Apr 15, 2015 at 3:36 AM, Andy Lutomirski <luto@amacapital.net> wrote:
>>>> We had been there before. To paraphrase another... meticulously honorable
>>>> person, "if you didn't want something relied upon, why have you put it into the
>>>> kernel?" Said person is on the record as having no problem whatsoever with
>>>> adding dependencies to the bottom of userland stack.
>>>
>>> It appears that, if kdbus is merged, upstream udev may end up requiring it:
>>>
>>> http://lists.freedesktop.org/archives/systemd-devel/2014-May/019657.html
>>
>> Why so surprised?
>> kdbus will be a major hard-dependency for every non-trivial userland.
>> Like cgroups...
>
> Maybe because things like cgroups, and kdbus in the future, solves a
> need that the developers in that area have to solve problems and
> provide functionality that their users require?

I agree that a high level bus is needed and dbus is not perfect.
But this does not mean that we need a in-kernel dbus in any case.

> Look, us kernel developers only work on one huge, multithreaded, global
> state binary. Our experience in multi-application interactions with
> shared state and permission requirements is usually quite limited. If
> you don't trust the developers of those programs outside the kernel,
> don't use them, there are still distros out there that don't require
> them.

We're all forced to use cgroups, systemd, udev unless we want to have busybox
as userland. That's a fact.
systemd and its dependencies are not a bad thing per se.
But we have to be very sure that new hard-dependencies are
in well shape before we push them into the kernel.
IMHO this is also Andy and Eris's point.

Thanks,
//richard