8364183: Shenandoah: Improve commit/uncommit handling

[shipilev]

While working on related bug, I found that Shenandoah commit/uncommit code has a few issues:

1. It throws Java OOME on commit/uncommit failures. These should actually be VM-level out of memory errors, so they are properly fatal.
2. Throwing OOME on uncommit looks fairly weird.
3. We are not zapping on the newly committed regions.

Additional testing:

• Linux x86_64 server fastdebug, hotspot_gc_shenandoah
• Linux x86_64 server fastdebug, all + -XX:+UseShenandoahGC

---

Progress

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Issue

• JDK-8364183: Shenandoah: Improve commit/uncommit handling (Enhancement - P4)

Reviewers

• William Kemper (@earthling-amzn - Reviewer)

Reviewing

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[openjdk]

@shipilev 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:

8364183: Shenandoah: Improve commit/uncommit handling

Reviewed-by: wkemper

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 46 new commits pushed to the master branch:

• 4669005: 8361912: ThreadsListHandle::cv_internal_thread_to_JavaThread does not deal with a virtual thread's carrier thread
• 3e4e5dd: 8364081: Shenandoah & GenShen logging improvement
• ea0b49c: 8362979: C2 fails with unexpected node in SuperWord truncation: CmpLTMask, RoundF
• ... and 43 more: https://git.openjdk.org/jdk/compare/594c080b2bde81a48ecccda85ac765218fc93856...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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[openjdk]

@shipilev The following labels will be automatically applied to this pull request:

• hotspot-gc
• shenandoah

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[mlbridge]

Webrevs

• 00: Full (a068757c)

[earthling-amzn]

LGTM