My guess is that you have some kind of JVMTI agent that adds objects tags. See: https://docs.oracle.com/en/java/javase/11/docs/specs/jvmti.html#objectTags The JVM holds an internal hashmap from object to tags. In older ZGCs releases we updated the object references in that hashmap during a pause. This was later moved to a concurrent phase with https://bugs.openjdk.org/browse/JDK-8212879. StefanK On 2022-09-05 11:19, 苗昌宇 wrote:

When I use ZGC on JDK11.0.8 in an online service, I find the time of Subphase weak roots JVMTIWeakExport is always increasing as our service is running. I want to know want made that？ Hope you will teach me.