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SubjectRe: Some -serious- BPF-related litmus tests
On Fri, May 22, 2020 at 11:44:07AM +0200, Peter Zijlstra wrote:
> On Thu, May 21, 2020 at 05:38:50PM -0700, Paul E. McKenney wrote:
> > Hello!
> >
> > Just wanted to call your attention to some pretty cool and pretty serious
> > litmus tests that Andrii did as part of his BPF ring-buffer work:
> >
> > https://lore.kernel.org/bpf/20200517195727.279322-3-andriin@fb.com/
> >
> > Thoughts?
>
> I find:
>
> smp_wmb()
> smp_store_release()
>
> a _very_ weird construct. What is that supposed to even do?

Indeed, it looks like one or the other of those is redundant (depending
on the context).

Also, what use is a spinlock that is accessed in only one thread?

Finally, I doubt that these tests belong under tools/memory-model.
Shouldn't they go under the new Documentation/ directory for litmus
tests? And shouldn't the patch update a README file?

Alan

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