First of all, congratulations on the great work with Generational ZGC. We are having great results.

We run our services using k8s, and a standard setup for the memory of the containers is to use 85% of the total memory for Java Heap and 15% for the rest. So, in a service running with 10Gb, 8.5Gb is allocated to the Java Heap, and 1.5Gb is Off-Heap memory.

When running with G1, 15% of Off-Heap memory is generally enough. But with Generational ZGC, we see an increase in out-of-memory container errors. It's not Java Heap Out of Memory, it's out-of-memory in the container. I started to decrease the ratio between Heap/Off-Heap memory, which was enough for some cases. However, there are services already running with 45% of memory allocated Off-Heap and still suffering from errors.

Is it expected that Generational ZGC requires more Off-Heap memory? Our containers run with around 80Gb of memory each, so for some cases, we are talking of more than 20Gb allocated Off-Heap in a pod running only the Java application.

Thanks!