Re: [PATCH -tip] Convert CONFIG_SMP=y powerpc defconfigs to TREE_RCU.

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

On Wed, Apr 08, 2009 at 02:46:23PM +0200, Ingo Molnar wrote:
> 
> * Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:
> 
> > On Sun, Apr 05, 2009 at 12:17:56PM +0200, Ingo Molnar wrote:
> > > 
> > > * Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:
> > > 
> > > > On Sat, Apr 04, 2009 at 09:21:58AM -0400, Josh Boyer wrote:
> > > > > On Fri, Apr 3, 2009 at 8:27 PM, Paul E. McKenney
> > > > > <paulmck@linux.vnet.ibm.com> wrote:
> > > > > > From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > > > > 
> > > > > Why would one want to do this?  The commit log doesn't explain the
> > > > > switch and why it's great.  Mostly because the commit log doesn't
> > > > > exist.  (I'll stop channeling Andrew now)
> > > > 
> > > > Indeed, I am sure that I will get the hang the relevant git 
> > > > commands at some point, but clearly am not yet there.
> > > > 
> > > > The thing that is great about this patch is that it is a step on 
> > > > the way to retiring Classic RCU entirely.
> > > 
> > > I'd suggest you dont do these dozens of defconfig updates at all - 
> > > arch maintainers can do this themselves, once the core kernel 
> > > default has been flipped.
> > 
> > I am of course personally quite happy with this approach in the 
> > short term, as I would only need to worry about one patch.
> > 
> > My one concern would be that we cannot retire Classic RCU until 
> > all the arch maintainers remove CONFIG_CLASSIC_RCU=y from their 
> > defconfig files. However, given that the attached script suffices, 
> > I am not too worried about that.
> 
> ah, that's not a real concern. Most defconfigs are stale all the 
> time, and arch maintainers typically refresh them at around rc7.
> (if at all) Kconfig will warn about (and ignore) stale entries.
> 
> So no, there's no requirement to touch defconfigs - to the contrary: 
> it has way too wide of a cross section with other trees to be really 
> practical to carry in the RCU tree.

Sounds good to me!!!  So, is http://lkml.org/lkml/2009/4/3/561
sufficient, or should I repost?

							Thanx, Paul