Re: [PATCH 2/3] jump_label: Provide static_key_slow_inc_nohp()

From: Thomas Gleixner
Date: Wed Apr 19 2017 - 05:09:15 EST


On Wed, 19 Apr 2017, Peter Zijlstra wrote:
> On Tue, Apr 18, 2017 at 10:50:43PM +0200, Thomas Gleixner wrote:
> > On Tue, 18 Apr 2017, Peter Zijlstra wrote:
> > > On Tue, Apr 18, 2017 at 12:46:29PM -0400, Steven Rostedt wrote:
> > > > On Tue, 18 Apr 2017 15:03:50 +0200
> > > > Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> > > >
> > > > > +++ b/kernel/padata.c
> > > > > @@ -1008,11 +1008,10 @@ static struct padata_instance *padata_al
> > > > > * parallel workers.
> > > > > *
> > > > > * @wq: workqueue to use for the allocated padata instance
> > > > > - *
> > > > > - * Must be called from a get_online_cpus() protected region
> > > >
> > > > Find the comment redundant?
> > >
> > > Once there's code that enforces it? Yes. Nobody reads comments
> > > ;-)
> >
> > Nobody enables lockdep either .....
>
> In the grand scheme of things, true. But there are more people running
> with lockdep enabled than there are people writing code, of which there
> are more than people reading relevant comments while writing code.
> Therefore having the lockdep annotation is two orders better than a
> comment ;-)
>
> Also, I would argue that an "assert" at the start of a function is a
> fairly readable 'comment' all by itself.
>
> In any case, I don't care too much. But I typically remove such comments
> when I stick a lockdep_assert_held() in.

I think that's wrong. We are striving for better documentation and the
kernel-doc comments above a function are part of that. Calling conventions
are definitely something which belongs there.

Thanks,

tglx