Messages in this thread | | | Date | Sun, 7 Oct 2012 18:04:11 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] make CONFIG_EXPERIMENTAL invisible and default |
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On Sun, Oct 07, 2012 at 04:18:54PM -0400, Dave Jones wrote: > On Sun, Oct 07, 2012 at 09:30:29AM -0700, Paul E. McKenney wrote: > > > > I think Kconfig is mostly what distro would like to use the thing is > > > the Kconfig text needs to be there upfront when its merged, not two > > > months later, since then it too late for a distro to notice. > > > > > > I'd bet most distros would read the warnings, but in a lot of cases > > > the warning don't exist until its too late. > > > > In the case of CONFIG_RCU_USER_QS you are quite right, the warning > > should have been there from the beginning and was not. I suppose you > > could argue that the warning was not sufficiently harsh in the case of > > CONFIG_RCU_FAST_NO_HZ, but either way it did get ignored: > > Maybe if we had a universally agreed upon tag for kconfig, like > "distro recommendation: N" that would make things obvious, and also allow > those of us unfortunate enough to maintain distro kernels to have something > to easily grep for. This would also catch the case when you eventually (hopefully) > flip from an N to a Y. > > There will likely still be some distros that will decide they know better > (and I'm pretty sure eventually I'll find reason to do so myself), but it at least > gives the feature maintainer the "I told you so" clause. > > Something we do quite often for our in-development kernels is enable something > that's shiny, new and unproven, and then when we branch for a release, we turn > it back off. It would be great if a lot of this kind of thing could be more automated.
One approach would be to have CONFIG_DISTRO, so that experimental features could use "depends on !DISTRO", but also to have multiple "BLEEDING" symbols. For example, given a CONFIG_DISTRO_BLEEDING_HPC and CONFIG_DISTRO_BLEEDING_RT, CONFIG_RCU_USER_QS might eventually use the following clause:
depends on !DISTRO || DISTRO_BLEEDING_HPC || DISTRO_BLEEDING_RT
A normal distro would define DISTRO, a distro looking to provide bleeding-edge HPC or real-time features would also define DISTRO_BLEEDING_HPC or DISTRO_BLEEDING_RT, respectively.
Does that make sense, or am I being overly naive?
Thanx, Paul
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