8369447: GenShen: Regulator thread may observe inconsistent states

[earthling-amzn]

The second commit on this PR is a one line code change plucked from another, more complicated and mostly unrelated change which fixes an issue with this PR.

• I confirm that I make this contribution in accordance with the OpenJDK Interim AI Policy.

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Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• JDK-8369447 needs maintainer approval
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8369447: GenShen: Regulator thread may observe inconsistent states (Bug - P4 - Requested)

Reviewers

• Kelvin Nilsen (@kdnilsen - no project role)
• Paul Hohensee (@phohensee - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk25u-dev.git pull/500/head:pull/500
$ git checkout pull/500

Update a local copy of the PR:
$ git checkout pull/500
$ git pull https://git.openjdk.org/jdk25u-dev.git pull/500/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 500

View PR using the GUI difftool:
$ git pr show -t 500

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk25u-dev/pull/500.diff

Using Webrev

Link to Webrev Comment

[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]

❗ 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]

⚠️ @earthling-amzn 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

• 01: Full - Incremental (61e3477f)
• 00: Full (96d616ea)

[kdnilsen]

Thanks for this backport.

[phohensee]

Looks like you're missing an issue for the code at new line 152.

[earthling-amzn]

/approval request This change prevents Shenandoah's generational mode's "regulator thread" from observing inconsistent states during safepoint operations. We would like to backport this because it could result in a range of misbehaviors from erroneous gc cycles to crashes.

[openjdk]

@earthling-amzn
8369447: The approval request has been created successfully.