RFR(S): 8229422: Taskqueue: Outdated selection of weak memory model platforms

Andrew Haley aph at redhat.com
Wed Jan 22 17:45:20 UTC 2020


On 1/22/20 11:59 AM, David Holmes wrote:
> I'm assuming the ordering requirement is to preserve the order as 
> expressed in the code. There is likely an assumption that by declaring 
> both as volatile that the the compiler will not reorder them; and that 
> the load_acquire will prevent the hardware from reordering them. I'm not 
> sure if either of those assumptions are actually valid.

The compiler won't reorder the stores, but the hardware will.

> But that doesn't explain the complete lack of barriers in set_empty.
> 
> The GC folk will need to chime in on the detailed semantic requirements 
> of this algorithm.

OK, but this looks like a separate problem: we can deal with it later
if we need to.

Thanks.

-- 
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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