RFR: 8324649: Shenandoah: refactor implementation of free set [v6]

[Kelvin Nilsen]

On Sat, 3 Feb 2024 01:42:44 GMT, Y. Srinivas Ramakrishna <ysr at openjdk.org> wrote:

>> Kelvin Nilsen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Rename and comments for _capacity_of and _used_by
>
> src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp line 683:
> 
>> 681: // move some of the mutator regions into the collector partition with the intent of packing collector memory into the
>> 682: //  highest (rightmost) addresses of the heap, with mutator memory consuming the lowest addresses of the heap.
>> 683: void ShenandoahFreeSet::find_regions_with_alloc_capacity(size_t &cset_regions) {
> 
> This method seems to belong to a public API of `ShenandoahRegionPartitions`. See also comment at the call site of this method.

There is a public API for prepare_to_rebuild() followed by finish_rebuild().  This public API is exercised by GenShen, which adjusts the sizes of old-gen and young-gen between the two calls.  Single-gen shenandoah does not distinguish between these two steps, because it has no notion of adjusting generation sizes.  Single-gen shenandoah invokes the public api rebuild(), which simply delegates to these two functions.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17561#discussion_r1477085137