RFR: 8247972: incorrect implementation of JVM TI GetObjectMonitorUsage [v21]

[Daniel D. Daugherty]

On Mon, 11 Mar 2024 18:08:14 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

>> Sorry I missed this response. I can't see a way to address spurious wakeups in this case as it needs to be a per-thread flag (so that each thread knows it was notified) but you don't know which thread will be notified in any given call to `notify()`. I also can't see how you can detect a spurious wakeup in this code. If they happen then a subtest may fail due to an unexpected number of re-entering threads.
>> I think we will just have to see how stable the test is in practice.
>
> Okay, thanks! I'll add some diagnostic code to catch spurious wakups.
> Let's see if we ever encounter any spurious wakeup in this test.

I think some sort of comment needs to be added here to document
the possibility of this code path being affect by a spurious wakeup.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17680#discussion_r1520260059