• 笔记

MetaspaceSize的坑

这几天生产上有台机器的Metaspace一直在告警，Metaspace使用达到了97%。使用-XX:MetaspaceSize=512m，告警也还在在持续，查看MC只有81536.0，显然这个参数没起作用。 也有人遇到类似的问题，并在openjdk上提过类似的bug，其实是一个注释的bug，最终在JDK-8151845中修复了。 Class metadata is deallocated when the corresponding Java class is unloaded. Java classes are unloaded as a result of garbage collection, and garbage collections may be induced in order to unload classes and deallocate class metadata. When the space committed for class metadata reaches a certain level (a high-water mark), a garbage collection is induced.