RFR: 8312610: GenShen: Old generation available is unintentionally restricted by mutator's available memory [v2]

[Y. Srinivas Ramakrishna]

On Mon, 24 Jul 2023 15:42:46 GMT, William Kemper <wkemper at openjdk.org> wrote:

>> Only young gen allocations should be restricted to memory in the mutator's view of the freeset.
>
> William Kemper has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Restore single-generation computation of "soft" available

Marked as reviewed by ysr (Committer).

src/hotspot/share/gc/shenandoah/shenandoahGlobalGeneration.cpp line 65:

> 63: 
> 64:   // Make sure the code below treats available without the soft tail.
> 65:   size_t soft_tail = max_capacity() - soft_max_capacity();

Would it be useful to assert here that `max_capacity() >= soft_max_capacity()` ?

src/hotspot/share/gc/shenandoah/shenandoahYoungGeneration.cpp line 106:

> 104: }
> 105: 
> 106: size_t ShenandoahYoungGeneration::soft_available() const {

So for young gen, `available` and `soft_available` are synonymous?

Can one just invoke the other and avoid the code duplication?

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PR Review: https://git.openjdk.org/shenandoah/pull/301#pullrequestreview-1543984618
PR Review Comment: https://git.openjdk.org/shenandoah/pull/301#discussion_r1272590845
PR Review Comment: https://git.openjdk.org/shenandoah/pull/301#discussion_r1272578175