Integrated: 8371672: G1: G1YoungGenSizer handling of NewRatio, NewSize and MaxNewSize

[Axel Boldt-Christmas]

On Wed, 12 Nov 2025 07:40:01 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

> G1YoungGenSizer ignores these values if they are not from the command line. Resulting in a different _sizer_kind than expected.
> The NewSize and MaxNewSize are also not bounded by the Initial and Max heap size respectively ([JDK-8370494](https://bugs.openjdk.org/browse/JDK-8370494)).
> 
> I suggest we rewrite this logic using `!FLAG_IS_DEFAULT` to always get the correct behaviour. And only use `FLAG_IS_CMDLINE` for issuing warnings to the user when we ergonomically change or ignore these values to be compatible.
> As well as adding the proper truncation for HeapSize incompatible values.
> 
> * Testing
>   * GHA
>   * Tier 1-5 on Oracle Supported Platforms

This pull request has now been integrated.

Changeset: ce1adf63
Author:    Axel Boldt-Christmas <aboldtch at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/ce1adf63ea1146fba4cf36c10dc5f1d33aa88000
Stats:     73 lines in 1 file changed: 49 ins; 1 del; 23 mod

8371672: G1: G1YoungGenSizer handling of NewRatio, NewSize and MaxNewSize
8370494: G1: NewSize not bounded by InitialHeapSize or MaxHeapSize

Reviewed-by: tschatzl, iwalulya

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PR: https://git.openjdk.org/jdk/pull/28255