The implementation of the JVM TI `GetObjectMonitorUsage` does not match the
spec.
The function returns the following structure:
typedef struct {
jthread owner;
jint entry_count;
jint waiter_count;
jthread* waiters;
jint notify_waiter_count;
jthread* notify_waiters;
} jvmtiMonitorUsage;
The following four fields are defined this way:
waiter_count [jint] The number of threads waiting to own this monitor
waiters [jthread*] The waiter_count waiting threads
notify_waiter_count [jint] The number of threads waiting to be notified by
this monitor
notify_waiters [jthread*] The notify_waiter_count threads waiting to be
notified
The `waiters` has to include all threads waiting to enter the monitor or to
re-enter it in `Object.wait()`.
The implementation also includes the threads waiting to be notified in
`Object.wait()` which is wrong.
The `notify_waiters` has to include all threads waiting to be notified in
`Object.wait()`.
The implementation also includes the threads waiting to re-enter the monitor in
`Object.wait()` which is wrong.
This update makes it right.
The implementation of the JDWP command `ObjectReference.MonitorInfo (5)` is
based on the JVM TI `GetObjectMonitorInfo()`. This update has a tweak to keep
the existing behavior of this command.
The follwoing JVMTI vmTestbase tests are fixed to adopt to the
`GetObjectMonitorUsage()` correct behavior:
jvmti/GetObjectMonitorUsage/objmonusage001
jvmti/GetObjectMonitorUsage/objmonusage003
The following JVMTI JCK tests have to be fixed to adopt to correct behavior:
vm/jvmti/GetObjectMonitorUsage/gomu001/gomu00101/gomu00101.html
vm/jvmti/GetObjectMonitorUsage/gomu001/gomu00101/gomu00101a.html
vm/jvmti/GetObjectMonitorUsage/gomu001/gomu00102/gomu00102.html
vm/jvmti/GetObjectMonitorUsage/gomu001/gomu00102/gomu00102a.html
A JCK bug will be filed and the tests have to be added into the JCK problem
list located in the closed repository by a separate sub-task before integration
of this update.
Also, please see and review the related CSR:
[8324677](https://bugs.openjdk.org/browse/JDK-8324677) Specification
clarification needed for JVM TI GetObjectMonitorUsage
Testing:
- tested with mach5 tiers 1-6
-------------
Commit messages:
- 8324677: Specification clarification needed for JVM TI GetObjectMonitorUsage
Changes: https://git.openjdk.org/jdk/pull/17680/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17680&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8324677
Stats: 25 lines in 5 files changed: 10 ins; 0 del; 15 mod
Patch: https://git.openjdk.org/jdk/pull/17680.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/17680/head:pull/17680
PR: https://git.openjdk.org/jdk/pull/17680
