RFR: 8272611: Use parallel heap inspection when print classhisto info in gc log [v2]

[Thomas Schatzl]

On Mon, 30 Aug 2021 11:31:46 GMT, Bin Liao <github.com+3094961+buddyliao at openjdk.org> wrote:

>> This patch helps to enhance the heap inspection with parallel threads when print classhisto info in gc log.
>> 
>> I have built it on linux x86_64 and run test-tier1 successfully
>> 
>> ---------
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>
> Bin Liao has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8272611: Use parallel heap inspection when print classhisto info in gc log

Changes requested by tschatzl (Reviewer).

src/hotspot/share/gc/shared/collectedHeap.cpp line 552:

> 550:     LogStream ls(lt);
> 551:     uint parallel_thread_num = safepoint_workers()->active_workers();
> 552:     VM_GC_HeapInspection inspector(&ls, false /* request full gc */, parallel_thread_num);

I would prefer the same issue would also be fixed in the other place (`ClassHistogramDCmd::execute`), using a static method as suggested. Otherwise the problem will exist forever.

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PR: https://git.openjdk.java.net/jdk/pull/5158