Passive mode in shenandoah is useful to diagnose barrier problems since it disables barriers by default[1]. We can enable barriers selectively and isolate problems. However, it does not support enabling ShenandoahCardBarrier[2].

We should have the support so we can troubleshoot card barrier related problems easier.


[1]: https://github.com/openjdk/jdk/blob/master/src/hotspot/share/gc/shenandoah/mode/shenandoahPassiveMode.cpp#L45-L50
[2]: https://github.com/openjdk/jdk/blob/master/src/hotspot/share/gc/shenandoah/mode/shenandoahPassiveMode.cpp#L55C31-L55C52