svn commit: r263424 - head/sys/arm/conf

[Ian Lepore]

On Fri, 2014-03-21 at 12:04 -0700, John-Mark Gurney wrote:
> Ian Lepore wrote this message on Fri, Mar 21, 2014 at 08:27 -0600:
> > On Fri, 2014-03-21 at 09:43 +0000, Andrew Turner wrote:
> > > On Thu, 20 Mar 2014 17:01:21 +0000 (UTC)
> > > Ruslan Bukin <br at FreeBSD.org> wrote:
> > > 
> > > > Author: br
> > > > Date: Thu Mar 20 17:01:21 2014
> > > > New Revision: 263424
> > > > URL: http://svnweb.freebsd.org/changeset/base/263424
> > > > 
> > > > Log:
> > > >   Disable debugging by default.
> > > 
> > > I don't like this on head. I have found a number of issues that were
> > > hidden because the kernel config most people were using for development
> > > had WITNESS, INVARIANTS and DIAGNOSTIC disabled.
> 
> I agree...  HEAD needs these to make sure they are production ready...
> 
> > I disagree.  Witness is essentially useless anymore, because there are
> > so many known LORs that nobody cares about when you report them that all
> > it does is spews noise.  Maybe it's useful when you're looking for a
> > particular problem, but leaving it on all the time has just lost its
> > value.
> 
> I wouldn't be tracking down an AVILA bug if it wasn't for INVARIANTS..
> 
> Also, your complaint is solely about WITNESS not the other ones...
> 
> Considering how many people are writing new drivers for ARM, and might
> be introducing locking issues w/ those new drivers, WITNESS should be
> included, plus, if you disable INVARIANTS, it means that all the
> lock assert functions will be turned off, and we might miss an odd
> calling stack which doesn't hold a lock or something...
> 
> If you're using HEAD for performance, it's easy to turn these off..
> 

My complaint is only about witness.

But... about being easy to turn off... how do they get turned off on
non-head branches?  Does re@ really have to go grovel through 77 config
files turning off diagnostic options?  Do we have to handle that
difference when merging things to stable branches?

Last time I tried to put something into arm/conf/DEFAULTS I got my hand
slapped, but... putting the diagnostic options in there on head and not
on stable branches would make the "touch 77 config files" problem go
away.

-- Ian