RFR: 8343226: Shenandoah: Move tenuring threshold constraint functions into shared constraints

[Y. Srinivas Ramakrishna]

On Tue, 29 Oct 2024 18:45:44 GMT, William Kemper <wkemper at openjdk.org> wrote:

> This change anticipates the [generational mode for Shenandoah](https://github.com/openjdk/jdk/pull/21273), which makes use of the `InitialTenuringThreshold` and `MaxTenuringThreshold` flags.

The change looks fine, but a few related comments. As far as I could tell:

1. With adaptive tenuring, GenShen makes use of neither of these options
2. Without adaptive tenuring, GenShen makes use of just InitialTenuringThreshold
3. G1 uses MaxTenuringThreshold, but not InitialTenuringThreshold

Given 2 & 3, I wonder if a comparison between them makes sense. It might, but worth checking the ways in which these are used. Given 3, then, would it need to also use the constraints function?

None of these are new issues (they predate your changes), so just leaving these comments for you to think about.

The changes look fine to me otherwise.

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Marked as reviewed by ysr (Committer).

PR Review: https://git.openjdk.org/shenandoah/pull/529#pullrequestreview-2410631926