8272327: Shenandoah: Avoid enqueuing duplicate string candidates

[shipilev]

Clean backport to improve Shenandoah.

Additional testing:

• Linux x86_64 fastdebug hotspot_gc_shenandoah

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8272327: Shenandoah: Avoid enqueuing duplicate string candidates

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk17u-dev pull/23/head:pull/23
$ git checkout pull/23

Update a local copy of the PR:
$ git checkout pull/23
$ git pull https://git.openjdk.java.net/jdk17u-dev pull/23/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 23

View PR using the GUI difftool:
$ git pr show -t 23

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk17u-dev/pull/23.diff

[bridgekeeper]

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[openjdk]

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

[openjdk]

@shipilev 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:

8272327: Shenandoah: Avoid enqueuing duplicate string candidates

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 2 new commits pushed to the master branch:

• 5ea8f48: 8277385: Zero: Enable CompactStrings support
• cb06a20: 8275586: Zero: Simplify interpreter initialization

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.

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

[mlbridge]

Webrevs

• 00: Full (23874523)

[shipilev]

Got the push approval.

/integrate

[openjdk]

Going to push as commit 79d97c4.
Since your change was applied there have been 6 commits pushed to the master branch:

• 13d3046: 8278115: gc/stress/gclocker/TestGCLockerWithSerial.java has duplicate -Xmx
• 6634879: 8278116: runtime/modules/LoadUnloadModuleStress.java has duplicate -Xmx
• 4b3a9e3: 8277992: Add fast jdk_svc subtests to jdk:tier3
• cc4a0b1: 8278016: Add compiler tests to tier{2,3}
• 5ea8f48: 8277385: Zero: Enable CompactStrings support
• cb06a20: 8275586: Zero: Simplify interpreter initialization

Your commit was automatically rebased without conflicts.

[openjdk]

@shipilev Pushed as commit 79d97c4.

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