8255527: Shenandoah: Let ShenadoahGCStateResetter disable barriers

[rkennke]

JDK-8255036 introduced a regression: the new ShenandoahGCStateResetter does not actually disable barriers: it only records old state (without changing it) and then restores that state (i.e a no-op).

Testing: hotspot_gc_shenandoah (also on conc-weakref branch, where the bug did manifest)

---

Progress

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

Issue

• JDK-8255527: Shenandoah: Let ShenadoahGCStateResetter disable barriers

Reviewers

• Aleksey Shipilev (@shipilev - Reviewer)
• Zhengyu Gu (@zhengyu123 - Reviewer) ⚠️ Review applies to e51fb43

Download

$ git fetch https://git.openjdk.java.net/jdk pull/899/head:pull/899
$ git checkout pull/899

[bridgekeeper]

👋 Welcome back rkennke! 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]

@rkennke The following labels will be automatically applied to this pull request:

• hotspot-gc
• shenandoah

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[mlbridge]

Webrevs

• 02: Full - Incremental (ae06bf8)
• 01: Full - Incremental (e51fb43)
• 00: Full (4515272)

[shipilev]

Minor nit, otherwise looks good.

[openjdk]

@rkennke 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:

8255527: Shenandoah: Let ShenadoahGCStateResetter disable barriers

Reviewed-by: shade, zgu

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 3 new commits pushed to the master branch:

• 3c4fc79: 8255299: Drop explicit zeroing at instantiation of Atomic* objects
• 6b2d11b: 8255246: AArch64: Implement BigInteger shiftRight and shiftLeft accelerator/intrinsic
• 591e7e2: 8255378: [Vector API] Remove redundant vector length check after JDK-8254814 and JDK-8255210

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.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[shipilev]

Looks even better.

[rkennke]

/integrate

[openjdk]

@rkennke Since your change was applied there have been 3 commits pushed to the master branch:

• 3c4fc79: 8255299: Drop explicit zeroing at instantiation of Atomic* objects
• 6b2d11b: 8255246: AArch64: Implement BigInteger shiftRight and shiftLeft accelerator/intrinsic
• 591e7e2: 8255378: [Vector API] Remove redundant vector length check after JDK-8254814 and JDK-8255210

Your commit was automatically rebased without conflicts.

Pushed as commit 1f00c3b.

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