252. Tackling G1 footprint improvements
Between JDK 8 and JDK 20, the G1 footprint has been improved by focusing on efficient metadata and freeing the memory as quickly as possible.
In order to optimize its footprint, G1 has passed through several changes, as follows.
Maintain only the needed metadata
In order to maintain only the needed metadata, JDK 11 is capable of concurrently (re)creating the needed data and freeing it as fast as possible. In JDK 17, the focus on the needed metadata has been reiterated and only the absolutely required data is kept around. Moreover, JDK 18 comes up with a denser representation of data. All these improvements are reflected in a smaller footprint.
Release memory
Starting with JDK 17, the G1 GC is capable of concurrently releasing memory (giving it back to the OS). This means that memory can be optimally reused and is available to serve other tasks.
