8366121: Hotspot Style Guide should document conventions for lock-free code

[dholmes-ora]

This is a topic that we, at Oracle, have discussed numerous times over the years and we have some simple guidelines that never get written down properly and which we/I tend to forget and then can't locate. To remedy that I would like to capture a few very simple style rules that exist for documentation purposes not necessarily correctness.

Thanks

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Issue

• JDK-8366121: Hotspot Style Guide should document conventions for lock-free code (Enhancement - P4)

Reviewers

• Stefan Karlsson (@stefank - Reviewer)
• Albert Mingkun Yang (@albertnetymk - Reviewer)
• Johan Sjölen (@jdksjolen - Reviewer)
• Julian Waters (@TheShermanTanker - Committer)
• Vladimir Kozlov (@vnkozlov - Reviewer)
• Kim Barrett (@kimbarrett - Reviewer)

Reviewing

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[openjdk]

@dholmes-ora This change now passes all automated pre-integration checks.

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8366121: Hotspot Style Guide should document conventions for lock-free code

Reviewed-by: stefank, ayang, jsjolen, jwaters, kvn, kbarrett

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At the time when this comment was updated there had been 68 new commits pushed to the master branch:

• ae96077: 8361614: Missing sub-int value validation in the Class-File API
• 937d61b: 8364751: ConstantBootstraps.explicitCast contradictory specification for null-to-primitive
• 86d6a2e: 8366147: ZGC: ZPageAllocator::cleanup_failed_commit_single_partition may leak memory
• ... and 65 more: https://git.openjdk.org/jdk/compare/1a7ac16d239cc1c244955a32baa8f5b32367790d...master

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[mlbridge]

Webrevs

• 00: Full (cd43591b)

[dholmes-ora]

Thanks for all the reviews.

I was contemplating withdrawing this as it has inspired Kim Barrett to work on an AtomicValue API (name may change) which makes this precise guidance moot most of the time. However, this added section can be used to document the need to use AtomicValue and there may be times use of AtomicValue is not applicable/appropriate.

@kvn could you please approve if you believe sufficient consensus exists for this. Thank you.

[vnkozlov]

Approved

[dholmes-ora]

Thanks @vnkozlov !

/integrate

[openjdk]

Going to push as commit d594ef3.
Since your change was applied there have been 68 commits pushed to the master branch:

• ae96077: 8361614: Missing sub-int value validation in the Class-File API
• 937d61b: 8364751: ConstantBootstraps.explicitCast contradictory specification for null-to-primitive
• 86d6a2e: 8366147: ZGC: ZPageAllocator::cleanup_failed_commit_single_partition may leak memory
• ... and 65 more: https://git.openjdk.org/jdk/compare/1a7ac16d239cc1c244955a32baa8f5b32367790d...master

Your commit was automatically rebased without conflicts.

[openjdk]

@dholmes-ora Pushed as commit d594ef3.

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