RFR: 8308614: Enabling JVMTI ClassLoad event slows down vthread creation by factor 10 [v4]

[Daniel D. Daugherty]

On Thu, 30 Nov 2023 20:58:41 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

> It is a little bit ugly to do it for each call site.
> The Handshake::execute() can do it instead, so its call sites could be simplified.
> BTW, it is done in the JvmtiHandshake::execute() and one can find it to be convenient.

Agreed, but it is intentional that direct uses of the three parameter
version of `Handshake::execute()` with `tlh == nullptr` require that
the caller understands the calling context. That means knowing where
your ThreadsListHandle is and not getting away with not having one
when the caller is current thread.

Higher layer callers of `Handshake::execute()` like `JvmtiHandshake::execute()`
or `JvmtiEventControllerPrivate::enter_interp_only_mode()` can make that
less strict choice if they choose to.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/16686#issuecomment-1834675329