8368670: Deadlock in JFR on event register + class load

[egahlin]

Could I have a review a PR that prevents a deadlock? The MetadataRepository::isEnabled check is an optimization that allows JFR to instrument disabled event classes lazily.

The available settings object is never modified after it has been created, so it is sufficient to publish it using a volatile.

Testing: jdk/jdk/jfr

Thanks
Erik

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Issue

• JDK-8368670: Deadlock in JFR on event register + class load (Bug - P2)

Reviewers

• Markus Grönlund (@mgronlun - Reviewer)

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8368670: Deadlock in JFR on event register + class load

Reviewed-by: mgronlun

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At the time when this comment was updated there had been 91 new commits pushed to the master branch:

• 8be1616: 8367609: serviceability/sa/ClhsdbPmap.java fails when built with Clang
• dfd3832: 8368966: Remove spurious VMStructs friends
• 5251405: 8368848: JShell's code completion not always working for multi-snippet inputs
• ... and 88 more: https://git.openjdk.org/jdk/compare/26b5708c47150023798a1546ba095c1b0b7807e1...master

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Webrevs

• 00: Full (a00d5c11)

[mgronlun]

Nice.

[egahlin]

/integrate

[openjdk]

Going to push as commit 5fccabf.
Since your change was applied there have been 97 commits pushed to the master branch:

• 1a03a1f: 8369033: Remove dead code in training data
• 7ad9bde: 8368630: java/net/httpclient/http3/H3ServerPushTest.java succeeds but fails in jtreg timeout
• 5252262: 8292984: Refactor internal container-related interfaces for clarity
• ... and 94 more: https://git.openjdk.org/jdk/compare/26b5708c47150023798a1546ba095c1b0b7807e1...master

Your commit was automatically rebased without conflicts.

[openjdk]

@egahlin Pushed as commit 5fccabf.

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