8366038: Thread::SpinRelease should use Atomic::release_store

[toxaart]

Hi, please consider the following changes:

Thread::SpinRelease() uses an OrderAccess::fence() to prevent loads and stores from within the critical section to float down out of the section. A full fence is expensive and it is an overkill on most platforms. Instead, one can achieve the same effect with Atomic::release_store().

Tested in tiers 1 - 3.

---

Progress

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

Issue

• JDK-8366038: Thread::SpinRelease should use Atomic::release_store (Enhancement - P4)

Reviewers

• David Holmes (@dholmes-ora - Reviewer)
• Albert Mingkun Yang (@albertnetymk - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/27035/head:pull/27035
$ git checkout pull/27035

Update a local copy of the PR:
$ git checkout pull/27035
$ git pull https://git.openjdk.org/jdk.git pull/27035/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 27035

View PR using the GUI difftool:
$ git pr show -t 27035

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/27035.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back toxaart! 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]

@toxaart 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:

8366038: Thread::SpinRelease should use Atomic::release_store

Reviewed-by: dholmes, ayang

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 30 new commits pushed to the master branch:

• ecf05ca: 8366693: Backout recent JavaLangAccess changes breaking the build
• 444a8fa: 8365501: Remove special AdapterHandlerEntry for abstract methods
• a029245: 8365983: Tests should throw SkippedException when SCTP not supported
• ... and 27 more: https://git.openjdk.org/jdk/compare/dbac620b996713087f0d1b1189e543e51a0bb09f...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 (@dholmes-ora, @albertnetymk) 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]

@toxaart The following label will be automatically applied to this pull request:

• hotspot-runtime

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 01: Full - Incremental (b6daa432)
• 00: Full (d72316fc)

[dholmes-ora]

Looks good, but I think we can shorten the mega-commentary. Thanks

[openjdk]

@toxaart
Your change (at version b6daa43) is now ready to be sponsored by a Committer.

[kimbarrett]

Thanks for reviews, let's /integrate

OpenJDK changes (not just HotSpot changes) should generally be open for 24 hours before being integrated.
https://openjdk.org/guide/ > Life of a PR > 7. Allow enough time for review

[toxaart]

Thanks for reviews, let's /integrate

OpenJDK changes (not just HotSpot changes) should generally be open for 24 hours before being integrated. https://openjdk.org/guide/ > Life of a PR > 7. Allow enough time for review

Right, I looked at the timestamp of the commit, not when the PR was marked as RFR.

[toxaart]

/touch

[openjdk]

@toxaart The pull request is being re-evaluated and the inactivity timeout has been reset.

[toxaart]

/integrate

[openjdk]

@toxaart
Your change (at version b6daa43) is now ready to be sponsored by a Committer.