RFR: 8226575: OperatingSystemMXBean should be made container aware

[Bob Vandette]

Daniil,

Looks good to me.

If there are any management jtreg tests, I’d run these since your changes to OperatingSystemMXBean will 
alter the behavior of these methods even for Linux hosts since cgroups is typically enabled causing the
container detection to report containerized.

It’s too bad getCpuLoad can’t detect that the cpuset is identical to the hosts in order to allow you to fallback to
getSystemCpuLoad0. 


Bob.


> On Dec 3, 2019, at 2:42 PM, Daniil Titov <daniil.x.titov at oracle.com> wrote:
> 
> Please review the change that makes OperatingSystemMXBean methods return container specific information
> rather than the host based data.
> 
> The webrev [1] is based on the code Andrew and Severin initially provided with some additional changes and combined
> with the spec update David made [3].
> 
> The webrev corrects the implementation for the free/total swap methods as Bob noted to subtract the total
> and free memory from the returned values.
> 
> It also corrects getCpuLoad() implementation, as Bob advised, to cover the case when CPU quotas are not active.
> 
> The webrev also takes into account the case when java.security.AccessControlException exception is thrown
> during the initialization of the container subsystem ( e.g.  when java.policy doesn’t grant "read" access to
> "/proc/self/mountinfo" file).
> 
> CSR for the spec changes [3] is approved.
> 
> Testing: Mach5 tiers1, tiers2, tiers3, tier4, tier5 (including open/test/hotspot/jtreg/containers/docker),  and tier6 tests passed .
> 
> [1] Webrev:  http://cr.openjdk.java.net/~dtitov/8226575/webrev.02/ 
> [2] Jira issue :https://bugs.openjdk.java.net/browse/JDK-8226575 
> [3] CSR https://bugs.openjdk.java.net/browse/JDK-8228428 
> 
> Thank you,
> -Daniil
> 
>