RFR: 8291555: Implement alternative fast-locking scheme [v52]

[David Holmes]

On Tue, 4 Apr 2023 12:57:38 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> Thanks @tstuefe . I see at that level if the object doesn't match the top of the lock-stack then we take the slow path. But then I'm lost - AFAICS the slow path is `InterpreterRuntime::monitorexit` and that doesn't have any fast-locking code in it at all ???
>
> I'm not sure what you mean. `InterpreterRuntime::monitorexit` will enter `ObjectSynchronizer::exit` which handles the fast-locking case under `if (LockingMode == 2)...`. Or am I misunderstanding you?
> 
> (I really wish for named constants instead of `1` and `2` constants though...)

Thanks @tstuefe .I misread something.

> (I really wish for named constants instead of 1 and 2 constants though...)

Yeah but then we are back at the "what do we call this" problem :)

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PR Review Comment: https://git.openjdk.org/jdk/pull/10907#discussion_r1157813697