8368152: Shenandoah: Incorrect behavior at end of degenerated cycle

[earthling-amzn]

Not clean, but conflict was trivial to resolve.

---

Progress

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• JDK-8368152 needs maintainer approval
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• Commit message must refer to an issue

Issue

• JDK-8368152: Shenandoah: Incorrect behavior at end of degenerated cycle (Bug - P4 - Approved)

Reviewers

• Kelvin Nilsen (@kdnilsen - no project role)
• Paul Hohensee (@phohensee - Reviewer)

Reviewing

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Update a local copy of the PR:
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$ git pull https://git.openjdk.org/jdk25u.git pull/241/head

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[bridgekeeper]

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[openjdk]

@earthling-amzn 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:

8368152: Shenandoah: Incorrect behavior at end of degenerated cycle

Reviewed-by: kdnilsen, phh

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At the time when this comment was updated there had been 32 new commits pushed to the master branch:

• a3854cf: 8368698: runtime/cds/appcds/aotCache/OldClassSupport.java assert(can_add()) failed: Cannot add TrainingData objects
• f5c2756: 8362204: test/jdk/sun/awt/font/TestDevTransform.java fails on Ubuntu 24.04
• ee6a040: 8365265: x86 short forward jump exceeds 8-bit offset in methodHandles_x86.cpp when using Intel APX
• ... and 29 more: https://git.openjdk.org/jdk25u/compare/3f9c665586705c833674ae998f49cabbc7e15615...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.

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[openjdk]

This backport pull request has now been updated with issue from the original commit.

[mlbridge]

Webrevs

• 00: Full (ed32b37a)

[phohensee]

Resolution in degen_event_message() looks ok.

[openjdk]

⚠️ @earthling-amzn This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[earthling-amzn]

/approval request This change fixes an error that causes the generational mode for Shenandoah to run back-to-back degenerated and full GCs without raising an out-of-memory error as expected. More importantly, it fixes an error that causes other Shenandoah modes to run a full gc unconditionally after every degenerated cycle (making a bad situation worse). We have tested this fix on jtreg tiers 1-3 and on various benchmarks: dacapo, specjvm, specjbb, extremem, and renaissance.

[openjdk]

@earthling-amzn
8368152: The approval request has been created successfully.

[earthling-amzn]

/integrate

[openjdk]

@earthling-amzn
Your change (at version ed32b37) is now ready to be sponsored by a Committer.

[shipilev]

/sponsor

[openjdk]

Going to push as commit ac9a03a.
Since your change was applied there have been 34 commits pushed to the master branch:

• c66d45a: 8365956: GenShen: Adaptive tenuring threshold algorithm may raise threshold prematurely
• 66de4b4: 8368732: RISC-V: Detect support for misaligned vector access via hwprobe
• a3854cf: 8368698: runtime/cds/appcds/aotCache/OldClassSupport.java assert(can_add()) failed: Cannot add TrainingData objects
• ... and 31 more: https://git.openjdk.org/jdk25u/compare/3f9c665586705c833674ae998f49cabbc7e15615...master

Your commit was automatically rebased without conflicts.

[openjdk]

@shipilev @earthling-amzn Pushed as commit ac9a03a.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.