RFR: JDK-8269650: Optimize gc-locker in [Get|Release]StringCritical for latin string

[Thomas Schatzl]

On Wed, 30 Jun 2021 11:55:49 GMT, Hamlin Li <mli at openjdk.org> wrote:

> Currently, JNI GetStringCritical locks gc locker for all strings including latin and non-latin until ReleaseStringCritical.
> But for latin, it's not necessary to still lock gc locker after GetStringCritical, as it's copied anyway whether obj pining is supported or not, so it's fine to unlock gc locker after GetStringCritical.

The gc team would like to ask you to wait on pushing/finishing this optimization after the fix for [JDK-8269661](https://bugs.openjdk.java.net/browse/JDK-8269661) bubbles up to JDK 18. JDK-8269661 is a P2 bug that should be fixed in JDK 17 too; it would be more convenient for us to fix it there first, then wait until we merge changes from there to 18.

Thanks.

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

PR: https://git.openjdk.java.net/jdk/pull/4637