RFR: 8368599: ShenandoahConcurrentMark could use ThreadsClaimTokenScope [v2]

[Aleksey Shipilev]

On Thu, 25 Sep 2025 11:00:18 GMT, Francesco Andreuzzi <fandreuzzi at openjdk.org> wrote:

>> Replace `StrongRootsScope` with `ThreadsClaimTokenScope` in `ShenandoahConcurrentMark::finish_mark_work` to be more precise with what is actually needed and why. Similar to #27385.
>> 
>> Test: tier1, and tier[1,2,3]_gc_shenandoah
>
> Francesco Andreuzzi has updated the pull request incrementally with one additional commit since the last revision:
> 
>   as field

Hold on a second.


class StrongRootsScope : public MarkScope {


...and:


MarkScope::MarkScope() {
  nmethod::oops_do_marking_prologue();
}

MarkScope::~MarkScope() {
  nmethod::oops_do_marking_epilogue();
}


So, what calls `nmethod::oops_do_marking_prologue`/`epilogue`, and do we know it is (not) needed?

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Changes requested by shade (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/27477#pullrequestreview-3267993745