RFR: 8338745: Intrinsify Continuation.pin() and Continuation.unpin() [v3]

[Vladimir Kozlov]

On Thu, 22 Aug 2024 12:10:37 GMT, Markus Grönlund <mgronlun at openjdk.org> wrote:

>> Greetings,
>> 
>> Please help review this change set that implements C2 intrinsics for jdk.internal.vm.Continuation.pin() and jdk.internal.vm.Continuation.unpin().
>> 
>> This work is a consequence of [JDK-8338417](https://bugs.openjdk.org/browse/JDK-8338417), which required us to introduce explicit pin constructs for Virtual threads in a relatively performance-sensitive path.
>> 
>> Testing: jdk_jfr, loom testing
>> 
>> Comment: I changed the type of the ContinuationEntry::_pin_count field from uint to uin32_t to make the size explicit and to access it uniformly from the intrinsic code using T_INT.
>> 
>> Thanks
>> Markus
>
> Markus Grönlund has updated the pull request incrementally with one additional commit since the last revision:
> 
>   JVMCI exportation

Marked as reviewed by kvn (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/20664#pullrequestreview-2255034428