8314551: More generic way to handshake GC threads with monitor deflation

[rkennke]

We currently handshake GC threads with monitor deflation by calling SuspendibleThreadSet::synchronize() and SuspendibleThreadSet::desynchronize(). This is somewhat problematic though, because GCs may use other mechanisms to sync their GC threads. In particular, ZGC uses ZRelocateQueue to do that.

Luckily, CollectedHeap comes with interfaces for exactly this purpose: CollectedHeap::safepoint_synchronize_begin() and CollectedHeap::safepoint_synchronize_end(). Those methods are implemented by ZGC to do the correct synchronization with ZRelocateQueue. All GCs which need that sort of synchronization are overriding these methods and delegate to STS methods, so we can replace the STS calls with the CollectedHeap calls.

Testing:

• hotspot_gc
• tier1

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
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• Commit message must refer to an issue

Issue

• JDK-8314551: More generic way to handshake GC threads with monitor deflation (Bug - P4)

Reviewers

• Johan Sjölen (@jdksjolen - Reviewer)
• Erik Österlund (@fisk - Reviewer)

Reviewing

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Update a local copy of the PR:
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$ git pull https://git.openjdk.org/jdk.git pull/15336/head

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[bridgekeeper]

👋 Welcome back rkennke! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@rkennke The following label will be automatically applied to this pull request:

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[mlbridge]

Webrevs

• 00: Full (befc54a3)

[jdksjolen]

Hi Roman,

This change looks good to me. I've asked for input from GC in case there are any considerations that are easily missed when only reading the surrounding code.

[openjdk]

@rkennke 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:

8314551: More generic way to handshake GC threads with monitor deflation

Reviewed-by: jsjolen, eosterlund

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 183 new commits pushed to the master branch:

• 6c821f5: 8315545: C1: x86 cmove can use short branches
• d7e4087: 8315369: [JVMCI] failure to attach to a libgraal isolate during shutdown should not be fatal
• d1cabe4: 8315566: [JVMCI] deadlock in JVMCI startup when bad option specified
• 94a74a0: 8315534: Incorrect warnings about implicit annotation processing
• 84425a6: 8315452: Erroneous AST missing modifiers for partial input
• 3094fd1: 8314662: jshell shows duplicated signatures of javap
• 0d52c82: 8310220: IGV: dump graph after each IGVN step at level 4
• adfc1d6: 8313323: javac -g on a java file which uses unnamed variable leads to ClassFormatError when launching that class
• 2dc930d: 8314997: Missing optimization opportunities due to missing try_clean_mem_phi() calls
• ab12c5d: 8315549: CITime misreports code/total nmethod sizes
• ... and 173 more: https://git.openjdk.org/jdk/compare/808bb1f7bc5025b4ab01e4e9057feebd253b95a7...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[rkennke]

Thanks!
/integrate

[openjdk]

Going to push as commit 31c4e03.
Since your change was applied there have been 349 commits pushed to the master branch:

• 89cb290: 8312165: Fix typos in java.desktop Swing
• 25f32f3: 8316160: Remove sun.misc.Unsafe.{shouldBeInitialized,ensureClassInitialized}
• 86dde5e: 8316001: GC: Make TestArrayAllocatorMallocLimit use createTestJvm
• 4f864fa: 8314136: Test java/net/httpclient/CancelRequestTest.java failed: WARNING: tracker for HttpClientImpl(42) has outstanding operations
• 4070829: 8315931: RISC-V: xxxMaxVectorTestsSmokeTest fails when using RVV
• d575968: 8316178: Better diagnostic header for CodeBlobs
• bfbc41c: 8315741: Open source few swing JFormattedTextField and JPopupMenu tests
• 0775bf2: 8316106: Open source few swing JInternalFrame and JMenuBar tests
• 4a63eb0: 8315834: Open source several Swing JSpinner related tests
• 8dc2d92: 8316190: Improve MemorySegment::toString
• ... and 339 more: https://git.openjdk.org/jdk/compare/808bb1f7bc5025b4ab01e4e9057feebd253b95a7...master

Your commit was automatically rebased without conflicts.

[openjdk]

@rkennke Pushed as commit 31c4e03.

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