从官网上获取到如下信息

-XX:MetaspaceSize=size

Sets the size of the allocated class metadata space that will trigger a garbage collection the first time it is exceeded. This threshold for a garbage collection is increased or decreased depending on the amount of metadata used. The default size depends on the platform.

这个信息比较微妙，没有描述具体机制是什么。depends on the platform又如何理解呢？