RFR: 8229169: False failure of GenericTaskQueue::pop_local on architectures with weak memory model

[Doerr, Martin]

Hi Jie and Kim,

I've run Jie's test for a while on a Power 8 machine, but the issue didn't show up.

> Martin, I assume you also saw JDK-8229020, also from Jie?  I'm
> somewhat surprised neither of these has been previously reported.
> Maybe these Loongson CPUs are more aggressively re-ordering reads than
> are other platforms?
There are other effects which may prevent re-ordering like data on same cache line, branch predicted differently, ...
So I'm not surprised we haven't observed all possible re-orderings.

Thanks, Jie, for improving the comment in your latest webrev. Looks good to me.
I appreciate that this gets fixed. Such problems are hard to find.

Best regards,
Martin