RFR: 8274788: Support archived heap objects in ParallelGC [v2]

[Calvin Cheung]

On Wed, 2 Mar 2022 16:08:58 GMT, Calvin Cheung <ccheung at openjdk.org> wrote:

>> With this change when the UseParallelGC is enabled, the CDS archived heap objects could be loaded
>> into the PSOldGen during VM bootstrap. This improves startup time since the module graph could be
>> loaded from the archive.
>> 
>> 
>> $ perf stat -r 40 -XX:+UseParallelGC -version
>> 
>> before: 0.069244290 seconds time elapsed            ( +-  0.49% )
>> after:    0.058555167 seconds time elapsed          ( +-  0.49% )
>> 
>> Passed CI tiers 1 - 4 tests.
>> 
>> Thanks @tschatzl for his help on GC changes.
>
> Calvin Cheung has updated the pull request incrementally with one additional commit since the last revision:
> 
>   update copyright header

Thanks Ioi, Albert, Thomas for the review.

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PR: https://git.openjdk.java.net/jdk/pull/7655