8364936: Shenandoah: Switch nmethod entry barriers to conc_instruction_and_data_patch

[JohnTortugo]

Hi all,

This pull request contains a backport of commit 81a1e8e1 from the openjdk/jdk repository.

The commit being backported was authored by Cesar Soares Lucas on 8 Sep 2025 and was reviewed by Fei Yang, Dingli Zhang, Kelvin Nilsen and William Kemper.

I had to manually resolve a merge conflict in TestHotSpotVMConfig.java because the original patch modified a region of the file that is not present in this repository version of the same file.

Thanks!

---

Progress

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

Issue

• JDK-8364936: Shenandoah: Switch nmethod entry barriers to conc_instruction_and_data_patch (Enhancement - P4)

Reviewers

• William Kemper (@earthling-amzn - Committer) ⚠️ Review applies to e157d1cb

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/218/head:pull/218
$ git checkout pull/218

Update a local copy of the PR:
$ git checkout pull/218
$ git pull https://git.openjdk.org/shenandoah-jdk21u.git pull/218/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 218

View PR using the GUI difftool:
$ git pr show -t 218

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/shenandoah-jdk21u/pull/218.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back cslucas! 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]

@JohnTortugo 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:

8364936: Shenandoah: Switch nmethod entry barriers to conc_instruction_and_data_patch

Reviewed-by: wkemper

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 8 new commits pushed to the master branch:

• 360af66: Merge
• dea855e: 8367388: Tests start to fail on JDK-21 after JDK-8351907
• 7fccea8: 8368152: Shenandoah: Incorrect behavior at end of degenerated cycle
• ... and 5 more: https://git.openjdk.org/shenandoah-jdk21u/compare/de04b203d3472c06598a365ef7e7038937bf9f8b...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.

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 (@earthling-amzn) 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).

[openjdk]

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

[mlbridge]

Webrevs

• 02: Full - Incremental (0020610c)
• 01: Full - Incremental (af29f617)
• 00: Full (49c12b6b)

[openjdk]

@JohnTortugo Please do not rebase or force-push to an active PR as it invalidates existing review comments. Note for future reference, the bots always squash all changes into a single commit automatically as part of the integration. See OpenJDK Developers’ Guide for more information.

[JohnTortugo]

/integrate

[openjdk]

@JohnTortugo
Your change (at version 0020610) is now ready to be sponsored by a Committer.

[earthling-amzn]

/sponsor

[openjdk]

Going to push as commit d9eaa69.
Since your change was applied there have been 8 commits pushed to the master branch:

• 360af66: Merge
• dea855e: 8367388: Tests start to fail on JDK-21 after JDK-8351907
• 7fccea8: 8368152: Shenandoah: Incorrect behavior at end of degenerated cycle
• ... and 5 more: https://git.openjdk.org/shenandoah-jdk21u/compare/de04b203d3472c06598a365ef7e7038937bf9f8b...master

Your commit was automatically rebased without conflicts.

[openjdk]

@earthling-amzn @JohnTortugo Pushed as commit d9eaa69.

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