RFR: 8247972: incorrect implementation of JVM TI GetObjectMonitorUsage [v23]

[Serguei Spitsyn]

On Mon, 11 Mar 2024 18:05:00 GMT, Daniel D. Daugherty <dcubed at openjdk.org> wrote:

>> Serguei Spitsyn has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 26 commits:
>> 
>>  - Merge
>>  - review: minor tweak in test description of ObjectMonitorUsage.java
>>  - review: addressed more comments on the fix and new test
>>  - rename after merge: jvmti_common.h to jvmti_common.hpp
>>  - Merge
>>  - review: update comment in threads.hpp
>>  - fix deadlock with carrier threads starvation in ObjectMonitorUsage test
>>  - resolve merge conflict for deleted file objmonusage003.cpp
>>  - fix a typo in libObjectMonitorUsage.cpp
>>  - fix potential sync gap in the test ObjectMonitorUsage
>>  - ... and 16 more: https://git.openjdk.org/jdk/compare/de428daf...b97b8205
>
> src/hotspot/share/prims/jvmtiEnvBase.cpp line 1483:
> 
>> 1481:   markWord mark = hobj->mark();
>> 1482:   ResourceMark rm(current_thread);
>> 1483:   GrowableArray<JavaThread*>* wantList = nullptr;
> 
> Thanks for refactoring `JvmtiEnvBase::get_object_monitor_usage()` to
> be much more clear. It was difficult to review in GitHub so I switched to
> the webrev frames view so that I could scroll the two sides back and forth
> and determine equivalence.

Good!

> src/hotspot/share/runtime/threads.hpp line 134:
> 
>> 132:   static unsigned print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form = false);
>> 133: 
>> 134:   // Get count Java threads that are waiting to enter or re-enter the specified monitor.
> 
> nit typo: s/count Java/count of Java/
> 
> Also this file needs a copyright year update.

Thanks, fixed now.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17680#discussion_r1520721501
PR Review Comment: https://git.openjdk.org/jdk/pull/17680#discussion_r1520722461