RFR: 8343840: Rewrite the ObjectMonitor lists [v2]

[Fredrik Bredberg]

On Thu, 27 Feb 2025 17:12:40 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> src/hotspot/share/runtime/objectMonitor.hpp line 46:
>> 
>>> 44: class ObjectWaiter : public CHeapObj<mtThread> {
>>> 45:  public:
>>> 46:   enum TStates : uint8_t { TS_UNDEF, TS_READY, TS_RUN, TS_WAIT, TS_ENTER };
>> 
>> TS_READY looks unused.
>
> Edit: this could be a trivial further PR.

And so does `TS_UNDEF`, but the enum value for `TS_UNDEF` will be zero and maybe there is some hidden "check for uninitialized `TStates` code" somewhere that stops working... A grep also finds:

`src/hotspot/share/prims/jvmtiRawMonitor.hpp:    enum TStates { TS_READY, TS_RUN, TS_WAIT, TS_ENTER }; `

So, since this is not really in the core part of this PR, I'd like to postpone that change to a later cleanup RFE.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23421#discussion_r1974278590