RFR: 8297247: Add GarbageCollectorMXBean for Remark and Cleanup pause time in G1 [v4]

[Yude Lin]

On Fri, 2 Dec 2022 14:16:41 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> Yude Lin has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Suggested changes to tests
>
> src/hotspot/share/gc/g1/g1MonitoringSupport.hpp line 254:
> 
>> 252: public:
>> 253:   G1YoungGCMonitoringScope(G1MonitoringSupport* monitoring_support, bool all_memory_pools_affected);
>> 254:   ~G1YoungGCMonitoringScope() { }
> 
> I think the empty destructor in child classes can be omitted, and the destructor in base class can probably be `protected`.

done

> test/hotspot/jtreg/gc/g1/TestRemarkCleanupMXBean.java line 31:
> 
>> 29:  * @summary Test that Remark and Cleanup are correctly reported by
>> 30:  *          a GarbageCollectorMXBean
>> 31:  * @requires vm.gc.G1 & vm.compMode != "Xcomp"
> 
> Why `vm.compMode != "Xcomp"`?

We were afraid that '-Xcomp' might bring some disruptive GCs to (an earlier version of) the test. Removed it, considering now that test is simplified.

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PR: https://git.openjdk.org/jdk/pull/11341