RFR: Add generations to freeset [v8]

[Kelvin Nilsen]

On Fri, 21 Apr 2023 18:31:09 GMT, Kelvin Nilsen <kdnilsen at openjdk.org> wrote:

>> src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp line 534:
>> 
>>> 532:         _heap->notify_mutator_alloc_words(waste >> LogHeapWordSize, true);
>>> 533:       }
>>> 534:       assert(probe_mutator_set(idx), "Must be mutator free: " SIZE_FORMAT, idx);
>> 
>> Looking at the assertions in `in_mutator_set()`, could you explain which of those wouldn't hold if you used `in_mutator_set()` in this assert, rather than `probe_mutator_set()`?
>
> There is a comment that describes the difference in the description of the probe_ membership functions.  Is this sufficient?

I've changed this abstraction.  in_free_set() asserts that the region has memory available to be allocated.  membership() reports which free set a region is in, but does not assert available memory.

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/250#discussion_r1180444763