New candidate JEP: 491: Synchronize Virtual Threads without Pinning

[Mark Reinhold]

https://openjdk.org/jeps/491

  Summary: Improve the scalability of Java code that uses synchronized
  methods and statements by arranging for virtual threads that block in
  such constructs to release their underlying platform threads for use
  by other virtual threads.  This will eliminate nearly all cases of
  virtual threads being pinnedjep444-pinning to platform threads, which
  severely restricts the number of virtual threads available to handle an
  application's workload.

- Mark