8354541: Remove Shenandoah post barrier expand loop opts

[JohnTortugo]

Hi all,

This pull request contains a backport of commit 4eae9b5b from the openjdk/jdk repository.

The commit being backported was authored by Cesar Soares Lucas on 17 Apr 2025 and was reviewed by Aleksey Shipilev.

Thanks!

---

Progress

• JDK-8354541 needs maintainer approval
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8354541: Remove Shenandoah post barrier expand loop opts (Bug - P4 - Requested)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk24u.git pull/204/head:pull/204
$ git checkout pull/204

Update a local copy of the PR:
$ git checkout pull/204
$ git pull https://git.openjdk.org/jdk24u.git pull/204/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 204

View PR using the GUI difftool:
$ git pr show -t 204

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk24u/pull/204.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]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

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

[openjdk]

⚠️ @JohnTortugo This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[mlbridge]

Webrevs

• 00: Full (0495f3cc)

[JohnTortugo]

/approval Remove post-barrier-expand loop optimizations in Shenandoah. These optimizations have been a burden to maintain. They are frequent source of bugs and they don't contribute much to performance after Shenandoah has migrated to LRB. The patch applies cleanly. Ran GHA Sanity Checks, local Tier 1-3 tests, Dacapo, Renaissance and SPEC benchmarks. Risk is low.

[openjdk]

@JohnTortugo usage: /approval [<id>] (request|cancel) [<text>]

[JohnTortugo]

/approval request for backport. Remove post-barrier-expand loop optimizations in Shenandoah. These optimizations have been a burden to maintain. They are frequent source of bugs and they don't contribute much to performance after Shenandoah has migrated to LRB. The patch applies cleanly. Ran GHA Sanity Checks, local Tier 1-3 tests, Dacapo, Renaissance and SPEC benchmarks. Risk is low.

[openjdk]

@JohnTortugo
8354541: The approval request has been created successfully.