Re: [PATCH v2 RFC 1/3] documentation: Add needed ACCESS_ONCE() calls to memory-barriers.txt

Paul E. McKenney
2013-11-22T18:54:30Z

On Fri, Nov 22, 2013 at 12:17:23PM +0100, Peter Zijlstra wrote:
> On Thu, Nov 21, 2013 at 02:32:30PM -0800, Paul E. McKenney wrote:
>
> > > > We could, but at the moment I would prefer the decrease in readability
> > > > to the copy-and-paste bugs that omit needed ACCESS_ONCE() calls.
> > > >
> > > > Is there some way to get both ACCESS_ONCE() and readability? An
> > > > abbreviation such as AO()? More easily distinguished variable names?
> > > > Something else?
> > >
> > > Use a form that looks less like C and thus defeats copy/paste?
> >
> > My concern with that approach is that there is likely to be a large
> > number of people who are likely to be willing and able to transcribe
> > from any reasonable non-C form to ACCESS_ONCE()-free C code. :-/
> >
> > But maybe you have something specific in mind?
>
> No, that was pretty much it. My issues is though that the subject matter
> is difficult enough without actively obfuscating the examples.
>
> Furthermore, people will find ways to get it wrong anyhow, if all they
> do is copy/paste without thought, then getting it wrong is pretty much
> guaranteed in this case. Memory ordering isn't something you can do
> without thinking.

One could argue that parsing the ACCESS_ONCE() calls will help them
realize that they actually need to think. ;-)

Thanx, Paul