8353692: Relax memory constraint on updating ObjectMonitorTable's item count

[zhengyu123]

It is a simple atomic counter for tracking hash table's load factor, only needs atomic guarantee.

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Issue

• JDK-8353692: Relax memory constraint on updating ObjectMonitorTable's item count (Enhancement - P4)

Reviewers

• Roman Kennke (@rkennke - Reviewer)
• David Holmes (@dholmes-ora - Reviewer)

Reviewing

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👋 Welcome back zgu! 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]

@zhengyu123 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:

8353692: Relax memory constraint on updating ObjectMonitorTable's item count

Reviewed-by: rkennke, dholmes

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At the time when this comment was updated there had been 88 new commits pushed to the master branch:

• 73bb647: 8353829: RISC-V: Auto-enable several more extensions for debug builds
• c26c575: 8353014: Exclude AOT tooling classes from AOT cache
• aec1fe0: 8351091: Shenandoah: global marking context completeness is not accurately maintained
• ... and 85 more: https://git.openjdk.org/jdk/compare/57df89c46449a19bb626fee2ea01c868e6dfb712...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.

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[mlbridge]

Webrevs

• 00: Full (362324a3)

[rkennke]

Makes sense! Thank you!

[dholmes-ora]

This seems safe. Not sure what the motivation is though? Generally we only make things relaxed when there is a performance hit to it not being relaxed. Otherwise its too hard to reason about why/when something can be relaxed and when not.

[zhengyu123]

This seems safe. Not sure what the motivation is though? Generally we only make things relaxed when there is a performance hit to it not being relaxed. Otherwise its too hard to reason about why/when something can be relaxed and when not.

@dholmes-ora I agree not making change to where memory semantics is not clear. But this one is pretty obvious, is it? Thanks.

[zhengyu123]

/integrate

Thanks @rkennke @dholmes-ora for the reviews.

[openjdk]

Going to push as commit da462cf.
Since your change was applied there have been 103 commits pushed to the master branch:

• f9d705b: 8351757: Test java/foreign/TestDeadlock.java#FileChannel_map timed out after passing
• 6c93ad4: 8351927: Change VirtualThread implementation to use use FJP delayed task handling
• 7aeaa3c: 8187520: Add --disable-java-warnings-as-errors configure option
• ... and 100 more: https://git.openjdk.org/jdk/compare/57df89c46449a19bb626fee2ea01c868e6dfb712...master

Your commit was automatically rebased without conflicts.

[openjdk]

@zhengyu123 Pushed as commit da462cf.

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