RFR: 8226575: OperatingSystemMXBean should be made container aware

[Andrew Azores]

Hi all,

Please review this change that addresses JDK-8226575 according to a
previous discussion on this list [0][1]. The webrev has been kindly
uploaded on my behalf by Severin Gehwolf, since I am not an author.

The initial problem was that the
com.sun.management.OperatingSystemMXBean was inconsistent about its
awareness of applicable container limits. On the one hand, the
(inherited) getAvailableProcessors() return value is consistent with
the container-aware Runtime.availableProcessors(). But on the other
hand, c.s.m.OperatingSystemMXBean's getTotalPhysicalMemorySize(),
getFreePhysicalMemorySize(), getTotalSwapSpaceSize(), and
getFreeSwapSpaceSize() returned values reflecting the physical host
machine with no awareness of container limits. getSystemCpuLoad() has
also been updated to use cgroup-accounted load calculation.

The fix applied is to use the JDK internal Metrics API to determine
container memory limits and CPU accounting and use these values
instead, if available, otherwise falling back on the pre-existing
native implementations.

bug:
https://bugs.openjdk.java.net/browse/JDK-8226575

webrev:
http://cr.openjdk.java.net/~sgehwolf/webrevs/aazores/JDK-8226575/01/webrev/

[0] 
http://mail.openjdk.java.net/pipermail/serviceability-dev/2019-June/028439.html
[1] 
http://mail.openjdk.java.net/pipermail/serviceability-dev/2019-July/028709.html

Thanks,

-- 
Andrew Azores
Software Engineer, OpenJDK Team
Red Hat