Hi Alan and Erik, Thanks for the review.
Webrev has been updated in http://cr.openjdk.java.net/~ddong/8238665/webrev.02/ Testing: jdk/jfr, java/lang/management/ all passed Summary: add a method in jdk.internal.misc.VM to get an unmodifiable buffer pool list. Cheers, Denghui Dong ------------------------------------------------------------------ From:Alan Bateman <alan.bate...@oracle.com> Send Time:2020年3月8日(星期日) 22:13 To:董登辉(卓昂) <denghui....@alibaba-inc.com>; Erik Gahlin <erik.gah...@oracle.com> Cc:hotspot-jfr-dev <hotspot-jfr-...@openjdk.java.net>; core-libs-dev <core-libs-dev@openjdk.java.net> Subject:Re: RFR: 8238665: Add JFR event for direct memory statistics On 05/03/2020 15:19, Denghui Dong wrote: Hi Alan and Erik, Sorry, I'm not sure if I fully understand what you mean. For this feature, I still think exporting jdk.internal.access to jdk.jfr is a good solutionsince there are some other packages has already exported to jdk.jfr in this module. I think it would be cleaner to put a helper in jdk.internal.misc so that JFR has access to the counters for each of the buffer pools. That would avoid additional plumbing when you extend it to mapped buffers. As I mentioned in one of the other mails, ManagementFactoryHelper.getBufferPoolMXBeans() could be changed to use it too. From the perspective of java.base then it's a lot nicer as anyone touching the buffer code doesn't need to have to concerned with direct access from code in java.management and jdk.jfr. -Alan
