8278824: Uneven work distribution when scanning heap roots in G1

[earthling-amzn]

Rebased onto 18. Original PR is here: openjdk/jdk#6840

---

Progress

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

Issue

• JDK-8278824: Uneven work distribution when scanning heap roots in G1

Reviewers

• Albert Mingkun Yang (@albertnetymk - Reviewer)
• Thomas Schatzl (@tschatzl - Reviewer)
• Paul Hohensee (@phohensee - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk18 pull/66/head:pull/66
$ git checkout pull/66

Update a local copy of the PR:
$ git checkout pull/66
$ git pull https://git.openjdk.java.net/jdk18 pull/66/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 66

View PR using the GUI difftool:
$ git pr show -t 66

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk18/pull/66.diff

[bridgekeeper]

👋 Welcome back wkemper! 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]

@earthling-amzn The following label will be automatically applied to this pull request:

• hotspot-gc

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[mlbridge]

Webrevs

• 00: Full (801c72ee)

[tschatzl]

Lgtm. Thanks for rebasing this.

Fwiw, the PR title needs to match the CR title to be able to integrate; I would prefer the CR title.

[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:

8278824: Uneven work distribution when scanning heap roots in G1

Reviewed-by: ayang, tschatzl, phh

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 6 new commits pushed to the master branch:

• 54b800d: 8271202: C1: assert(false) failed: live_in set of first block must be empty
• 2945b78: 8279195: Document the -XX:+NeverActAsServerClassMachine flag
• 6588bed: 8278889: AArch64: [vectorapi] VectorMaskLoadStoreTest.testMaskCast() test fail
• 04ad668: 8279204: [BACKOUT] JDK-8278413: C2 crash when allocating array of size too large
• 730f670: 8268297: jdk/jfr/api/consumer/streaming/TestLatestEvent.java times out
• 9d5ae2e: 8279076: C2: Bad AD file when matching SqrtF with UseSSE=0

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.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@albertnetymk, @tschatzl, @phohensee) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

[earthling-amzn]

/integrate

[openjdk]

@earthling-amzn
Your change (at version 801c72e) is now ready to be sponsored by a Committer.

[phohensee]

/sponsor

[openjdk]

Going to push as commit b4b0328.
Since your change was applied there have been 6 commits pushed to the master branch:

• 54b800d: 8271202: C1: assert(false) failed: live_in set of first block must be empty
• 2945b78: 8279195: Document the -XX:+NeverActAsServerClassMachine flag
• 6588bed: 8278889: AArch64: [vectorapi] VectorMaskLoadStoreTest.testMaskCast() test fail
• 04ad668: 8279204: [BACKOUT] JDK-8278413: C2 crash when allocating array of size too large
• 730f670: 8268297: jdk/jfr/api/consumer/streaming/TestLatestEvent.java times out
• 9d5ae2e: 8279076: C2: Bad AD file when matching SqrtF with UseSSE=0

Your commit was automatically rebased without conflicts.

[openjdk]

@phohensee @earthling-amzn Pushed as commit b4b0328.

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

[earthling-amzn]

/backport jdk17u-dev

[openjdk]

@earthling-amzn Unknown command backport - for a list of valid commands use /help.