RFR: 8364343: Virtual Thread transition management needs to be independent of JVM TI [v4]

[David Holmes]

On Fri, 21 Nov 2025 00:35:38 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Patricio Chilano Mateo has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Rename VM methods for endFirstTransition/startFinalTransition
>
> src/hotspot/share/runtime/mountUnmountDisabler.cpp line 162:
> 
>> 160:   // be executed once we go back to Java. If this is an unmount, the handshake that the
>> 161:   // disabler executed against this carrier thread already provided the needed synchronization.
>> 162:   // This matches the release fence in xx_enable_for_one()/xx_enable_for_all().
> 
> Subtle. Do we have comments where the fences are to ensure people realize the fence is serving this purpose?

I also forgot to suggest a wording change: say "pairs with" rather than "matches". Reading back through I realize now I have misunderstood many of these comments.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28361#discussion_r2548189421