On Tue, 27 Sep 2022, Tobias Burnus wrote:
> Ignoring (1), does the overall patch and this part otherwise look okay(ish)?
>
>
> Caveat: The .sys scope works well with >= sm_60 but not does not handle
> older versions. For those, the __atomic_{load/store}_n are used. I do not
> see a good solution beyond documentation. In the way it is used (one
> thread only setting only on/off flag, no atomic increments etc.), I think
> it is unlikely to cause races without .sys scope, but as always is
> difficult to rule out some special unfortunate case where it does. At
> lease we do have now some documentation (in general) - which still needs
> to be expanded and improved. For this feature, I did not add any wording
> in this patch: until the feature is actually enabled, it would be more
> confusing than helpful.
If the implication is that distros will ship a racy-by-default implementation,
unless they know about the problem and configure for sm_60, then no, that
doesn't look fine to me. A possible solution is not enabling a feature that
has a known correctness issue.
Alexander
