Netty 4.1.x direct memory monitoring

Question

Question is a follow up question regarding this forum exchange: Direct buffer allocation .

Problem is that at some point there was a change introduced to how default implementation is allocating buffers in direct memory, which is not using JMX com.codahale.metrics.jvm.BufferPoolMetricSet any more.

Is there a way to monitor direct memory usage without setting:

-Dio.netty.maxDirectMemory=0

Answer 1

它通过PooledByteBufAllocator和UnpooledByteBufAllocator上的指标（获取器） UnpooledByteBufAllocator 。