8368086: G1: Use ThreadsClaimTokenScope in G1CMRemarkTask

[albertnetymk]

Replace StrongRootsScope with ThreadsClaimTokenScope in G1ConcurrentMark::finalize_marking to be more precise with what is actually needed and why.

Test: tier1

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Issue

• JDK-8368086: G1: Use ThreadsClaimTokenScope in G1CMRemarkTask (Enhancement - P4)

Reviewers

• Francesco Andreuzzi (@fandreuz - Author)
• Stefan Karlsson (@stefank - Reviewer)
• Ivan Walulya (@walulyai - Reviewer)

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[openjdk]

@albertnetymk This change now passes all automated pre-integration checks.

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After integration, the commit message for the final commit will be:

8368086: G1: Use ThreadsClaimTokenScope in G1CMRemarkTask

Reviewed-by: fandreuzzi, stefank, iwalulya

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At the time when this comment was updated there had been 25 new commits pushed to the master branch:

• 682fd78: 8366678: Use JUnit in test/langtools/tools/javac
• 5efaa99: 8367298: ZGC: Enhance zaddress type system's assert messages
• a1b43c3: 8368087: ZGC: Make ZStatLoad::print() logging conditional on os::loadavg support
• ... and 22 more: https://git.openjdk.org/jdk/compare/94a301a70e19be284f406ebb6d8b94b6f96e1a24...master

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[openjdk]

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[mlbridge]

Webrevs

• 00: Full (b810c396)

[stefank]

One difference between the two code paths is the check to see if the number of threads are > 0. Are we guaranteed that active_workers are > 0 here?

[albertnetymk]

Are we guaranteed that active_workers are > 0 here?

Yes. There is at least one active worker, or we fail at startup, as shown in WorkerThreads::initialize_workers.

[albertnetymk]

Thanks for review.

/integrate

[openjdk]

Going to push as commit 4445463.
Since your change was applied there have been 27 commits pushed to the master branch:

• f10fbe1: 8368072: Remove redundant arguments of MarkingNMethodClosure
• 258fcf9: 8367987: Memory leak in MemBaseline: Must delete _vma_allocations
• 682fd78: 8366678: Use JUnit in test/langtools/tools/javac
• ... and 24 more: https://git.openjdk.org/jdk/compare/94a301a70e19be284f406ebb6d8b94b6f96e1a24...master

Your commit was automatically rebased without conflicts.

[openjdk]

@albertnetymk Pushed as commit 4445463.

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