8267257: Shenandoah: Always deduplicate strings when it is enabled during full gc

[zhengyu123]

Full GC should recover as much memory as possible, so it should deduplicate all string candidates regardless their ages, when it is enabled. Also enhanced TestStringDedup.java test to ensure all candidates are deduplicated.

Note: Full GC does not preserve age bits, so current implementation will not deduplicate any strings even with back-to-back full GCs.

Test:

• hotspot_gc_shenandoah

---

Progress

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Issue

• JDK-8267257: Shenandoah: Always deduplicate strings when it is enabled during full gc

Reviewers

• Roman Kennke (@rkennke - Reviewer)

Reviewing

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[bridgekeeper]

👋 Welcome back zgu! 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]

@zhengyu123 The following labels will be automatically applied to this pull request:

• hotspot-gc
• shenandoah

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[mlbridge]

Webrevs

• 00: Full (1b2a69bb)

[rkennke]

Looks good to me. Thank you!

[openjdk]

@zhengyu123 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:

8267257: Shenandoah: Always deduplicate strings when it is enabled during full gc

Reviewed-by: rkennke

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 41 new commits pushed to the master branch:

• 88b1142: 8267357: build breaks with -Werror option on micro benchmark added for JDK-8256973
• 6ef46ce: 8231672: Simplify the reference processing parallelization framework
• 392f962: 8267151: C2: Don't create dummy Opaque1Node for outmost unswitched IfNode
• 0cf7e57: 8267239: C1: RangeCheckElimination for % operator if divisor is IntConstant
• 2d407e1: 8267293: vmTestbase/vm/mlvm/anonloader/stress/oome/metaspace/Test.java fails when JTREG_JOBS > 25
• 70f6c67: 8233380: CHT: Node allocation and freeing
• 2563a6a: 8266962: Add arch supporting check for "Op_VectorLoadConst" before creating the node
• 4954383: 8267364: Remove mask.incr which is introduced by JDK-8256973
• c2b50f9: 8266480: Implicit null check optimization does not update control of hoisted memory operation
• 3f883e8: 8267351: runtime/cds/SharedBaseAddress.java fails on x86_32 due to Unrecognized VM option 'UseCompressedOops'
• ... and 31 more: https://git.openjdk.java.net/jdk/compare/dd5a84c68c4f6128c3568c6f4fc1302c6aaadf01...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.

[zhengyu123]

/integrate

[openjdk]

@zhengyu123 Since your change was applied there have been 45 commits pushed to the master branch:

• 12050f0: 8266651: Convert Table method parameters from String to Content
• e749f75: 8267304: Bump global JTReg memory limit to 768m
• e858dd6: 8267361: JavaTokenizer reads octal numbers mistakenly
• 1b93b81: 8267133: jdk/jfr/event/gc/collection/TestG1ParallelPhases.java fails with Not expected phases: RestorePreservedMarks, RemoveSelfForwardingPtr: expected true, was false
• 88b1142: 8267357: build breaks with -Werror option on micro benchmark added for JDK-8256973
• 6ef46ce: 8231672: Simplify the reference processing parallelization framework
• 392f962: 8267151: C2: Don't create dummy Opaque1Node for outmost unswitched IfNode
• 0cf7e57: 8267239: C1: RangeCheckElimination for % operator if divisor is IntConstant
• 2d407e1: 8267293: vmTestbase/vm/mlvm/anonloader/stress/oome/metaspace/Test.java fails when JTREG_JOBS > 25
• 70f6c67: 8233380: CHT: Node allocation and freeing
• ... and 35 more: https://git.openjdk.java.net/jdk/compare/dd5a84c68c4f6128c3568c6f4fc1302c6aaadf01...master

Your commit was automatically rebased without conflicts.

Pushed as commit 0b49f5a.

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