RFR: 8352256: ObjectSynchronizer::quick_notify misses JFR event notification path [v3]

[Markus Grönlund]

On Tue, 1 Apr 2025 21:05:11 GMT, Markus Grönlund <mgronlun at openjdk.org> wrote:

>> Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:
>> 
>>  - Merge branch 'master' into JDK-8352256-quick-notify-jfr
>>  - Review comment
>>  - Fix
>
> src/hotspot/share/runtime/objectMonitor.cpp line 2054:
> 
>> 2052:   }
>> 2053: 
>> 2054:   quick_notifyAll(current);
> 
> From a JFR perspective, we need threads in state VM or Java for writing events that refer to artifacts; both states are equivalent for epoch management. You can also have threads in native writing JFR events, but only if the event fields are scalars, not foreign keys. However, the thread cannot capture a stack trace.

A JavaThread in state VM or Java running the JFR commit code will not perform a transition or block for a safepoint. It is not waitfree (yet) however because of the JfrStacktrace_lock.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24097#discussion_r2023693404