RFR: 8327000: GenShen: Integrate updated Shenandoah implementation of FreeSet into GenShen [v8]

[Y. Srinivas Ramakrishna]

On Thu, 13 Jun 2024 22:22:01 GMT, Kelvin Nilsen <kdnilsen at openjdk.org> wrote:

>> The mainline implementation of ShenandoahFreeSet was recently updated.  This PR integrates the upstream changes
>> into Generational Shenandoah.
>
> Kelvin Nilsen has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Minor refinements to test programs
>   
>   TestAllocIntArrays: comments to explain behavior.
>   TestOldGrowthTriggers: reduce the number of loop iterations so this test
>   will not time out on less powerful test platforms.

src/hotspot/share/gc/shenandoah/shenandoahFreeSet.hpp line 290:

> 288: 
> 289:   // Satisfy collector allocation request req by finding memory that matches affiliation from within the
> 290:   // free partition associated with which_partition.

Returns the address allocated and `in_new_region` indicates if the allocation was
satisfied from a new, previously empty region.

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/440#discussion_r1645292351