RFR: 8357650: ThreadSnapshot to take snapshot of thread for thread dumps [v2]

[Alex Menkov]

On Wed, 28 May 2025 13:35:44 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> src/hotspot/share/classfile/javaClasses.cpp line 1875:
>> 
>>> 1873: 
>>> 1874: oop java_lang_Thread::park_blocker(oop java_thread) {
>>> 1875:   return java_thread->obj_field_acquire(_park_blocker_offset);
>> 
>> Where is the releasing store that pairs with this load-acquire?
>
> Thread.parkBlocker is declared volatile but all access is done in opaque mode, so maybe this should MO_RELAXED?
> 
> In any case, I think we might have to drop the sampling of exclusiveOwnerThread for now. This can only be tested to see if it's the current thread, and only after a volatile-state of the state.

made access MO_RELAXED

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PR Review Comment: https://git.openjdk.org/jdk/pull/25425#discussion_r2113109398