8273545: Remove Thread::is_GC_task_thread()

[pliden]

I propose we remove Thread::is_GC_task_thread(). It's used only in two places (one in ZGC, and one assert in ParallelGC), and those two uses can be replaced by calls to is_Worker_thread() instead. Removing is_GC_task_thread() also allows us to clean out some stuff from WorkGang/GangWorker.

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Progress

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Issue

• JDK-8273545: Remove Thread::is_GC_task_thread()

Reviewers

• Stefan Karlsson (@stefank - Reviewer) ⚠️ Review applies to ca94d76
• Coleen Phillimore (@coleenp - Reviewer) ⚠️ Review applies to ca94d76
• Aleksey Shipilev (@shipilev - Reviewer)

Reviewing

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[bridgekeeper]

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[openjdk]

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[mlbridge]

Webrevs

• 01: Full - Incremental (0165c4a9)
• 00: Full (ca94d767)

[stefank]

Looks good

[openjdk]

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

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

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

8273545: Remove Thread::is_GC_task_thread()

Reviewed-by: stefank, coleenp, shade

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At the time when this comment was updated there had been 2 new commits pushed to the master branch:

• 4866eaa: 8273409: Receiver type narrowed by CCP does not always trigger post-parse call devirtualization
• 5ca26cb: 8273433: Enable parallelism in vmTestbase_nsk_sysdict tests

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[coleenp]

Looks good to me. So Worker threads could always do operations during a safepoint? They're NamedThreads so they can run across safepoints? Thanks.

[pliden]

Looks good to me. So Worker threads could always do operations during a safepoint? They're NamedThreads so they can run across safepoints? Thanks.

What a worker thread can and can not do with regards to safepoints depends on the GC, and what WorkGang instance in that GC. In other words, there's no strong connection between the two that is true for all GCs and all WorkGangs.

[shipilev]

Looks fine.

[pliden]

Thanks all for reviewing!

/integrate

[openjdk]

Going to push as commit 185eaca.
Since your change was applied there have been 7 commits pushed to the master branch:

• dd1209e: 8268885: duplicate checkcast when destination type is not first type of intersection type
• ef4a532: 8263773: Reenable German localization for builds at Oracle
• 96614da: 8272903: Missing license header in ArenaAllocator.java
• e3bda63: 8273489: Zero: Handle UseHeavyMonitors on all monitorenter paths
• c81690d: 8273498: compiler/c2/Test7179138_1.java timed out
• 4866eaa: 8273409: Receiver type narrowed by CCP does not always trigger post-parse call devirtualization
• 5ca26cb: 8273433: Enable parallelism in vmTestbase_nsk_sysdict tests

Your commit was automatically rebased without conflicts.

[openjdk]

@pliden Pushed as commit 185eaca.

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