Re: [PATCH 0/4] Allow schedulers to be selectable through Kconfig

[Ian Campbell <ian.campbell@citrix.com>]

On Thu, 2016-01-07 at 07:37 -0700, Jan Beulich wrote:
> > > > On 07.01.16 at 15:01, <jonathan.creekmore@gmail.com> wrote:
> 
> > Ian Campbell writes:
> > 
> > > I don't see this as contrary to your stated goals (e.g. ripping out all the
> > > other schedulers), but I consider you to be within the expert camp for
> > > wanting to do so (and having the chops to handle whatever pieces you find
> > > yourselves with). I have no objections at all to allowing experts such as
> > > yourselves to configure things and I applaud you for doing this in an
> > > upstream way (it is the right thing to do).
> > > 
> > > My concern is that while you rightly consider yourselves expert enough and
> > > are building something for a specific (and AIUI targeted) use case many
> > > normal users tend to think that if they are expert enough to find and flip
> > > the switch then they are expert enough to deal with the consequences, when
> > > they are not and/or they do not have the specific use case which the switch
> > > was added to support i.e. they want common or garden Xen and we want that
> > > to mean the same for everyone.
> > > 
> > > It's those people (including general purpose distro maintainers) who I
> > > think need to be strongly discouraged from messing with these options
> > > because there will be a strong gravity towards them doing so.
> > 
> > So, if I add a patch in a v3 of this series that introduces a
> > CONFIG_EXPERT option and hides all of the scheduler options behind that,
> > would that be acceptible? That is a proposal that was mentioned on this
> > thread before.

Thinking about it I think I'd avoid the specific name CONFIG_EXPERT due to
the expectations which Linux's use of the name has set.

If we invert the sense then we could call it e.g. CONFIG_STANDARD_PLATFORM
and default it to y, I expect it will be easier to discourage people from
turning such an option off than to discourage them from turning something
like CONFIG_EXPERT on.

> With me asking for that option to not have a visible prompt by default,
> but nevertheless being settable. I do realize that this may not be
> possible with the current kconfig tool, but that's imo the only way to
> keep people from playing with expert options just because they see
> there's a prompt. No textual warning will help this, I'm afraid.

While I have reasonably strong opinions about this issue, I do not think
they warrant forking Kconfig over.

With a suitably strong wording IMHO we have covered ourselves sufficiently.

Ian.