8312321: GenShen: Remembered set scan may encounter garbage objects

[earthling-amzn]

During a global cycle, regions with no live objects may be reclaimed early (before evacuation). Once this happens, we must coalesce and fill any dead objects in old regions because they may hold pointers into the reclaimed regions (even if the gc is cancelled before coalesce and fill). A subsequent scan of the remembered set may crash if it encounters these objects.

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Issue

• JDK-8312321: GenShen: Remembered set scan may encounter garbage objects (Bug - P4)

Reviewers

• Kelvin Nilsen (@kdnilsen - Committer) ⚠️ Review applies to b819a47c

Reviewing

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[mlbridge]

Webrevs

• 01: Full - Incremental (2b959c8f)
• 00: Full (b819a47c)

[openjdk]

@earthling-amzn This change now passes all automated pre-integration checks.

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8312321: GenShen: Remembered set scan may encounter garbage objects

Reviewed-by: kdnilsen

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At the time when this comment was updated there had been 2 new commits pushed to the master branch:

• 514fd37: 8312422: GenShen: In-place region promotion state may carry over when evacuation fails
• e754b19: 8312322: GenShen: Cancelled GCs may become stuck in self-cancellation loop

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[earthling-amzn]

/integrate

[openjdk]

Going to push as commit 0fbfe19.
Since your change was applied there have been 2 commits pushed to the master branch:

• 514fd37: 8312422: GenShen: In-place region promotion state may carry over when evacuation fails
• e754b19: 8312322: GenShen: Cancelled GCs may become stuck in self-cancellation loop

Your commit was automatically rebased without conflicts.

[openjdk]

@earthling-amzn Pushed as commit 0fbfe19.

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