8381561: G1: Cleanup patch in preparation for eager reclamation of flat arrays

[stefank]

During the review of openjdk/valhalla#2255 there were some discussion about the code structure that was being proposed. To not make structural changes like this in the valhalla branch, I'm going to propose the changes to openjdk/jdk and then the valhalla changes can be kept to a minimum.

This is what the valhalla changes would look like:
stefank/valhalla@lworld_g1_eager_baseline...stefank:valhalla:lworld_g1_eager

WDYT?

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8381561: G1: Cleanup patch in preparation for eager reclamation of flat arrays (Enhancement - P4)

Reviewers

• Albert Mingkun Yang (@albertnetymk - Reviewer) Review applies to a3ad1abf
• Ivan Walulya (@walulyai - Reviewer) Review applies to a3ad1abf
• Thomas Schatzl (@tschatzl - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/30549/head:pull/30549
$ git checkout pull/30549

Update a local copy of the PR:
$ git checkout pull/30549
$ git pull https://git.openjdk.org/jdk.git pull/30549/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 30549

View PR using the GUI difftool:
$ git pr show -t 30549

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/30549.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back stefank! 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]

@stefank 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:

8381561: G1: Cleanup patch in preparation for eager reclamation of flat arrays

Reviewed-by: tschatzl, ayang, iwalulya

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 36 new commits pushed to the master branch:

• c267c84: 8358766: Improve detection of changes to print IGVN steps
• 9cf2b68: 8381003: [REDO] Mitigate Neoverse-N1 erratum 1542419 negative impact on GCs and JIT performance
• 0b803bd: 8380103: Perfdata shared memory file flock failures
• ... and 33 more: https://git.openjdk.org/jdk/compare/c18e3a3377e67f50ab065d1ac9365c7d43950fb6...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.

[openjdk]

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

• hotspot-gc

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 01: Full - Incremental (3653a45e)
• 00: Full (a3ad1abf)

[stefank]

This check has been removed. Marking closures should follow the metadata and there's no need to check if it should.

[stefank]

I've run this through tier1-3.

[walulyai]

Nit!

[tschatzl]

Would be great to have the log message improved like @walulyai suggested, but looks great otherwise.

[stefank]

Thanks all for reviewing!
/integrate

[openjdk]

Going to push as commit 69c4a21.
Since your change was applied there have been 36 commits pushed to the master branch:

• c267c84: 8358766: Improve detection of changes to print IGVN steps
• 9cf2b68: 8381003: [REDO] Mitigate Neoverse-N1 erratum 1542419 negative impact on GCs and JIT performance
• 0b803bd: 8380103: Perfdata shared memory file flock failures
• ... and 33 more: https://git.openjdk.org/jdk/compare/c18e3a3377e67f50ab065d1ac9365c7d43950fb6...master

Your commit was automatically rebased without conflicts.

[openjdk]

@stefank Pushed as commit 69c4a21.

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

[openjdk]

@tschatzl The target repository valhalla is not a valid target for backports.
List of valid target repositories: openjdk/jdk, openjdk/jdk11u, openjdk/jdk11u-dev, openjdk/jdk17u, openjdk/jdk17u-dev, openjdk/jdk21u, openjdk/jdk21u-dev, openjdk/jdk25u, openjdk/jdk25u-dev, openjdk/jdk26u, openjdk/jdk8u, openjdk/jdk8u-dev, openjdk/jfx, openjdk/jfx17u, openjdk/jfx21u, openjdk/jfx25u, openjdk/jfx26u, openjdk/lilliput-jdk17u, openjdk/lilliput-jdk21u, openjdk/lilliput-jdk25u, openjdk/shenandoah-jdk21u, openjdk/shenandoah-jdk8u.
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