Re: [PATCH locking/Documentation 1/2] Add note of release-acquire store vulnerability

Peter Zijlstra
2016-09-30T12:51:26Z

On Fri, Sep 30, 2016 at 05:14:03AM -0700, Paul E. McKenney wrote:
> PowerPC does not "obscure" stores, so both stores really are there and
> the lwsync really has effect on all CPUs. From what I understand, even
> CPUs that do obscure stores only do so in the case of repeated stores
> by the same CPU to the same variable, and the above litmus test doesn't
> have this.
>
> So all the stores happen, and each CPU's stores are at least locally
> ordered.

OK, when I'm not sure I ever understood the case where smp_wmb() went
wonky on PPC, sadly I cannot now find the email where you mentioned
that :/