8273541: Cleaner Thread creates with normal priority instead of MAX_PRIORITY - 2

[kabutz]

…of MAX_PRIORITY-2 during refactoring

Appears in Java 17 for the first time.

During refactoring, the priority was changed from Thread.MAX_PRIORITY - 2 to instead state Thread.MIN_PRIORITY - 2, which results in a negative priority, and is thus set to Thread.NORM_PRIORITY. Thus the Cleaner by default now has threads with priority 5, instead of 8.

The change was done in git revision # 992b500 and label 8261036 by Claes Redestad

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Progress

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

Issue

• JDK-8273541: Cleaner Thread creates with normal priority instead of MAX_PRIORITY - 2

Reviewers

• Aleksey Shipilev (@shipilev - Reviewer)
• Alan Bateman (@AlanBateman - Reviewer)
• Lance Andersen (@LanceAndersen - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/5439/head:pull/5439
$ git checkout pull/5439

Update a local copy of the PR:
$ git checkout pull/5439
$ git pull https://git.openjdk.java.net/jdk pull/5439/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 5439

View PR using the GUI difftool:
$ git pr show -t 5439

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk/pull/5439.diff

[bridgekeeper]

👋 Welcome back kabutz! 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]

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

• core-libs

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[AlanBateman]

I've created JDK-8273541 to track this.

[shipilev]

This looks good. @cl4es might want to confirm that change was not intentional.

[shipilev]

Please change the PR title to "8273541: Cleaner Thread creates with normal priority instead of MAX_PRIORITY - 2" to get it automatically hooked by bots.

[kabutz]

Why would jcheck say "This PR contains no changes" @shipilev ?

[AlanBateman]

It looks like d621cdd has undone the changes.

[kabutz]

It looks like d621cdd has undone the changes.

Thanks Alan!

[openjdk]

⚠️ @kabutz This pull request contains merges that bring in commits not present in the target repository. Since this is not a "merge style" pull request, these changes will be squashed when this pull request in integrated. If this is your intention, then please ignore this message. If you want to preserve the commit structure, you must change the title of this pull request to Merge <project>:<branch> where <project> is the name of another project in the OpenJDK organization (for example Merge jdk:master).

[mlbridge]

Webrevs

• 00: Full (8c69beb0)

[shipilev]

This looks fine to me.

[openjdk]

@kabutz 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:

8273541: Cleaner Thread creates with normal priority instead of MAX_PRIORITY - 2

Reviewed-by: shade, alanb, lancea

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:

• c1e39fa: 8273482: Remove "foreground work" concept from WorkGang
• 2eaf374: 8272698: LoadNode::pin is unused
• 792281d: 8264517: C2: make MachCallNode::return_value_is_used() only available for x86

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.

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 (@shipilev, @AlanBateman, @LanceAndersen) 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).

[LanceAndersen]

This should be ready to integrate so please enter /integrate in a new comment and then it can be sponsored.

Thank you

[kabutz]

/integrate

[openjdk]

@kabutz
Your change (at version 8c69beb) is now ready to be sponsored by a Committer.

[cl4es]

This looks good. @cl4es might want to confirm that change was not intentional.

Completely unintentional, and perplexing since it's not a simple copy-paste error..

[cl4es]

/sponsor

[openjdk]

Going to push as commit 4e6de5f.
Since your change was applied there have been 3 commits pushed to the master branch:

• c1e39fa: 8273482: Remove "foreground work" concept from WorkGang
• 2eaf374: 8272698: LoadNode::pin is unused
• 792281d: 8264517: C2: make MachCallNode::return_value_is_used() only available for x86

Your commit was automatically rebased without conflicts.

[openjdk]

@cl4es @kabutz Pushed as commit 4e6de5f.

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

[kabutz]

This looks good. @cl4es might want to confirm that change was not intentional.

Completely unintentional, and perplexing since it's not a simple copy-paste error..

The thread priorities in Java are the wrong way round, (high is 10, low is 1) so I was not surprised by this mistake.

[mlbridge]

Mailing list message from David Holmes on core-libs-dev:

On 11/09/2021 5:24 am, kabutz wrote:

On Fri, 10 Sep 2021 14:08:05 GMT, Claes Redestad <redestad at openjdk.org> wrote:

This looks good. @cl4es might want to confirm that change was not intentional.

Completely unintentional, and perplexing since it's not a simple copy-paste error..

The thread priorities in Java are the wrong way round, (high is 10, low is 1) so I was not surprised by this mistake.

They are not "the wrong way around" they followed Solaris Global
Dispatch Priorities (and Windows priorities for that matter). It makes a
lot more sense than systems where a "higher priority" means a lower
numerical priority value IMO.

:)

Cheers,
David