8325574: Shenandoah: Simplify and enhance reporting of requested GCs

[earthling-amzn]

Shenandoah distinguishes between 'implicit' and 'explicit' GC requests. The distinction is used to decide whether or not a request is serviced concurrently or with a full GC. The data collected is also included in the end-of-process report. This change simplifies handling of these requests and adds a tally of the underlying GC causes to the end-of-process report.

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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-8325574: Shenandoah: Simplify and enhance reporting of requested GCs (Task - P4)

Reviewers

• Y. Srinivas Ramakrishna (@ysramakrishna - Reviewer) ⚠️ Review applies to ce06e434
• Kelvin Nilsen (@kdnilsen - no project role) ⚠️ Review applies to ce06e434
• Aleksey Shipilev (@shipilev - Reviewer) ⚠️ Review applies to 8d174e81

Reviewing

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Update a local copy of the PR:
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$ git pull https://git.openjdk.org/jdk.git pull/17795/head

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[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]

@earthling-amzn The following labels will be automatically applied to this pull request:

• hotspot-gc
• shenandoah

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

[mlbridge]

Webrevs

• 03: Full - Incremental (dfa31c98)
• 02: Full - Incremental (8d174e81)
• 01: Full - Incremental (9115c470)
• 00: Full (ce06e434)

[ysramakrishna]

LGTM.

[openjdk]

@earthling-amzn 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:

8325574: Shenandoah: Simplify and enhance reporting of requested GCs

Reviewed-by: ysr, kdnilsen, shade

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 77 new commits pushed to the master branch:

• 09d4936: 8252136: Several methods in hotspot are missing "static"
• f6e2851: 8316340: (bf) Missing {@inheritdoc} for exception in MappedByteBuffer::compact
• 53878ee: 8325643: G1: Refactor G1FlushHumongousCandidateRemSets
• 130f429: 8325403: Add SystemGC JMH benchmarks
• 9c852df: 8318966: Some methods make promises about Java array element alignment that are too strong
• 737b4c5: 8323883: JFR AssertionError: Missing object ID 15101
• 61f2493: 8325767: Serial: Move transform_stack_chunk out of TenuredGeneration::promote
• 8dc5976: 8325809: JFR: Remove unnecessary annotation
• 84965ea: 8322630: Remove ICStubs and related safepoints
• 0c2def0: 8325653: Erroneous exhaustivity analysis for primitive patterns
• ... and 67 more: https://git.openjdk.org/jdk/compare/10beb3184e14e2714cd836029680a8b2d3fd5011...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.

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

[shipilev]

The simplification in ShenandoahControlThread::run_service looks very nice. I think we can make the code more straight-forward:

[shipilev]

Looks good, with minor nits.

[earthling-amzn]

/integrate

[openjdk]

Going to push as commit b823fa4.
Since your change was applied there have been 77 commits pushed to the master branch:

• 09d4936: 8252136: Several methods in hotspot are missing "static"
• f6e2851: 8316340: (bf) Missing {@inheritdoc} for exception in MappedByteBuffer::compact
• 53878ee: 8325643: G1: Refactor G1FlushHumongousCandidateRemSets
• 130f429: 8325403: Add SystemGC JMH benchmarks
• 9c852df: 8318966: Some methods make promises about Java array element alignment that are too strong
• 737b4c5: 8323883: JFR AssertionError: Missing object ID 15101
• 61f2493: 8325767: Serial: Move transform_stack_chunk out of TenuredGeneration::promote
• 8dc5976: 8325809: JFR: Remove unnecessary annotation
• 84965ea: 8322630: Remove ICStubs and related safepoints
• 0c2def0: 8325653: Erroneous exhaustivity analysis for primitive patterns
• ... and 67 more: https://git.openjdk.org/jdk/compare/10beb3184e14e2714cd836029680a8b2d3fd5011...master

Your commit was automatically rebased without conflicts.

[openjdk]

@earthling-amzn Pushed as commit b823fa4.

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