Re: [GIT PULL tools] Linux kernel memory model

From: Paul E. McKenney
Date: Fri Feb 02 2018 - 03:41:29 EST


On Fri, Feb 02, 2018 at 12:46:03PM +0800, Boqun Feng wrote:
> On Wed, Jan 31, 2018 at 05:17:28PM -0800, Paul E. McKenney wrote:
> [...]
> > > - A long term question: have you considered and would it make sense to generate a
> > > memory-barriers.txt like file directly into Documentation/locking/, using the
> > > formal description? That way any changes/extensions/fixes to the model could be
> > > tracked on a high level, without readers having to understand the formal
> > > representation.
> >
> > I hadn't considered this at all, actually. ;-)
> >
> > The sections of memory-barriers.txt dealing with MMIO ordering would need
> > to stay hand-generated, but they are a very small fraction of the total.
> > The herd7 tool is capable of generating cool diagrams sort of like
> > this one: https://static.lwn.net/images/2017/mm-model/rmo-acyclic.png,
> > which might replace at least some of the hand-generated ASCII-art
> > diagrams.
>
> Which reminds me, one thing we could start with is to try to convert all
> the examples with litmus tests. Has this been done somewhere (e.g. in
> your litmus github repo)? If not, I can try if you think that's a good
> idea.

That would be very helpful, thank you!

There are probably some that are already in the litmus-tests directory,
but I suspect that most are not yet converted. So please do!

Thanx, Paul

> Regards,
> Boqun
>
> > Although I do confess harboring some skepticism about being able to
> > generated high-quality text, there is no denying that it would be
> > valuable to be able to do so.
> >
> > > In any case, the base commit is certainly nice and clean and I've pulled it into
> > > tip:locking/core for a v4.17 merge.
> >
> > Very good!
> >
> > > I believe these additional improvements (to the extent you agree with doing them!)
> > > could/should be done as add-on commits on top of this existing commit.
> >
> > Sounds good!
> >
> > Would you prefer a pull request or a patch series for these?
> >
> > Thanx, Paul
> >