8264324: Simplify allocation list management in OopStorage::reduce_deferred_updates

[kimbarrett]

Please review this cleanup of the allocation list management performed by OopStorage::reduce_deferred_updates. Part of its job is to take a block whose allocation set has changed and update its place in the allocation list accordingly. The old code has somewhat confusing logic and does unnecessary work in some cases. The new code is clearer and avoids that excess work. (I'm not sure what I was thinking when I wrote the old code.)

Testing:
mach5 tier1
I've also been using this patch for some time under other in-development changes that make heavy use of OopStorage.

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Progress

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Issue

• JDK-8264324: Simplify allocation list management in OopStorage::reduce_deferred_updates

Reviewers

• Thomas Schatzl (@tschatzl - Reviewer) ⚠️ Review applies to fefc97e
• Albert Mingkun Yang (@albertnetymk - Committer) ⚠️ Review applies to 79739d6

Reviewing

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Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/3227/head:pull/3227
$ git checkout pull/3227

Update a local copy of the PR:
$ git checkout pull/3227
$ git pull https://git.openjdk.java.net/jdk pull/3227/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 3227

View PR using the GUI difftool:
$ git pr show -t 3227

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk/pull/3227.diff

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[openjdk]

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[mlbridge]

Webrevs

• 02: Full - Incremental (8f03199)
• 01: Full - Incremental (79739d6)
• 00: Full (fefc97e)

[tschatzl]

Seem good.

[openjdk]

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

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8264324: Simplify allocation list management in OopStorage::reduce_deferred_updates

Reviewed-by: tschatzl, ayang

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[kimbarrett]

Thanks for reviews @tschatzl and @albertnetymk .

[kimbarrett]

/integrate

[openjdk]

@kimbarrett Pushed as commit 4ea6abf.

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