RFR: 8238665: Add JFR event for direct memory statistics

[Alan Bateman]

On 05/03/2020 02:44, Denghui Dong wrote:
> Hi Erik,
> Updated.
> Webrev: http://cr.openjdk.java.net/~ddong/8238665/webrev.01/
>
ManagementFactoryHelper has a method to get the list of MXBeans for the 
buffer pools. That could be easily changed to return an unmodifable 
list. That would allow you to emit statistics for memory-mapped files 
too (the current patch seems to be limited to emitting stats for direct 
buffers).

-Alan.