On Sat, Feb 03, 2018 at 05:10:06PM -0500, Alan Stern wrote:
> On Sat, 3 Feb 2018, Paul E. McKenney wrote:
>
> > Please see below for an initial patch to this effect. This activity
> > proved to be more productive than expected for these tests, which certainly
> > supports our assertion that locking needs more testing...
> >
> > MP+polocks.litmus
> > MP+porevlocks.litmus
> >
> > These are allowed by the current model, which surprised me a bit,
> > given that even powerpc would forbid them. Is the rationale
> > that a lock-savvy compiler could pull accesses into the lock's
> > critical section and then reorder those accesses? Or does this
> > constitute a bug in our model of locking?
> >
> > (And these were allowed when I wrote recipes.txt, embarrassingly
> > enough...)
> >
> > Z6.0+pooncelock+poonceLock+pombonce.litmus
> >
> > This was forbidden when I wrote recipes.txt, but now is allowed.
> > The header comment for smp_mb__after_spinlock() makes it pretty
> > clear that it must be forbidden. So this one is a bug in our
> > model of locking.
>
> I just tried testing these under the most recent version of herd, and
> all three were forbidden.
And they do for me as well once I upgraded to the most recent version of
herd. Whew!!!
Boy, we weren't kidding when we said that you need to us the latest
and greatest herd7, now were we? ;-)
Thanx, Paul
