8319253: [BACKOUT] Change LockingMode default from LM_LEGACY to LM_LIGHTWEIGHT

[dholmes-ora]

The change of default locking mode for JDK 22 is being restored to LM_LEGACY due to remaining stability and performance issues that have been uncovered with lightweight locking, for which solutions have not yet been found, but are being actively investigated. We will make the change in JDK 23 instead.

This reverts commit 455cfae.

Testing: tiers 1-3 (our internal tier 3 testing includes a set of tests using mode LM_LIGHTWEIGHT so that it will continue to experience some testing until we flip things back in December)

Thanks.

---

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Issue

• JDK-8319253: [BACKOUT] Change LockingMode default from LM_LEGACY to LM_LIGHTWEIGHT (Sub-task - P3)

Reviewers

• Thomas Stuefe (@tstuefe - Reviewer)
• Aleksey Shipilev (@shipilev - Reviewer)
• Stefan Karlsson (@stefank - Reviewer)
• Daniel D. Daugherty (@dcubed-ojdk - Reviewer)

Reviewing

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[bridgekeeper]

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[openjdk]

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[mlbridge]

Webrevs

• 00: Full (7d065630)

[tstuefe]

Seems reasonable if regrettable.

[openjdk]

@dholmes-ora 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:

8319253: [BACKOUT] Change LockingMode default from LM_LEGACY to LM_LIGHTWEIGHT

Reviewed-by: stuefe, shade, stefank, dcubed

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 7 new commits pushed to the master branch:

• 7c7f8ea: 8319456: jdk/jfr/event/gc/collection/TestGCCauseWith[Serial|Parallel].java : GC cause 'GCLocker Initiated GC' not in the valid causes
• 7bc8e4c: 8294980: test/jdk/java/lang/invoke 15 test classes use experimental bytecode library
• e841897: 8319374: JFR: Remove instrumentation for exception events
• cd9719b: 8319306: Serial: Remove TenuredSpace::verify
• 1e687b4: 8316719: C2 compilation still fails with "bad AD file"
• 8555e0f: 8319318: bufferedStream fixed case can be removed
• 73c5f60: 8319556: Harmonize interface formatting in the FFM API

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
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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[shipilev]

The revert looks good.

[dcubed-ojdk]

Thumbs up. This is a trivial fix.

[dholmes-ora]

Thanks for all the reviews!

/integrate

[openjdk]

Going to push as commit f4ab952.
Since your change was applied there have been 13 commits pushed to the master branch:

• c137b17: 8187655: jdk.lambda.vm.InterfaceAccessFlagsTest.testPrivateMethodCall needs update after nestmates support
• fa331d7: 8319184: RISC-V: improve MD5 intrinsic
• 4c0f6c6: 8311961: Update Manual Test Groups for ATR JDK22
• a6785e4: 8318915: Enhance checks in BigDecimal.toPlainString()
• 7d25f1c: 8319423: Improve Year.isLeap by checking divisibility by 16
• 59e9981: 8319376: ParallelGC: Forwarded objects found during heap inspection
• 7c7f8ea: 8319456: jdk/jfr/event/gc/collection/TestGCCauseWith[Serial|Parallel].java : GC cause 'GCLocker Initiated GC' not in the valid causes
• 7bc8e4c: 8294980: test/jdk/java/lang/invoke 15 test classes use experimental bytecode library
• e841897: 8319374: JFR: Remove instrumentation for exception events
• cd9719b: 8319306: Serial: Remove TenuredSpace::verify
• ... and 3 more: https://git.openjdk.org/jdk/compare/cc4b0d9217ed27a9555dc82f0a4247bf9b703f2b...master

Your commit was automatically rebased without conflicts.

[openjdk]

@dholmes-ora Pushed as commit f4ab952.

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