RFR: 8253971: ZGC: Flush mark stacks after processing concurrent roots

[Albert Mingkun Yang]

On Sun, 4 Oct 2020 11:14:59 GMT, Per Liden <pliden at openjdk.org> wrote:

>> I wonder if it makes sense to unify this PR with the same logic in `ZMarkRootsTask` to a function, sth like
>> `PostRootsScan`. Additionally, such flushing is only needed if `ParallelGCThreads != ConcGCThreads`, right?
>
> @albertnetymk Yes, the problem stems from ZWorkers::nconcurrent() potentially being less than ZWorkers::nworkers().

Thanks for the explanation. I am curious if it's worth the trouble to make the flush conditional.

-------------

PR: https://git.openjdk.java.net/jdk/pull/495