RFR: 8246037: Shenandoah: update man pages to mention -XX:+UseShenandoahGC [v2]

[Rui Li]

On Mon, 25 Aug 2025 11:18:24 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Rui Li has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Comment for aggressive. Indent.
>
> src/java.base/share/man/java.md line 2899:
> 
>> 2897: 
>> 2898:     `satb`
>> 2899:     :   Snapshot-at-the-beginning concurrent GC (three pass mark-evac-update).
> 
> This is a long-standing problem with the name. It kinda implies `generational` is not `satb`. It actually is. Maybe we should rename `satb` to `single` or something. A lot of bikeshedding would ensue.

Renaming the value of an existing jvm arg sounds intrusive, unless we can add an alias link from `satb` to `single`? Alternatively, we probably can add comment in generational to indicate it's also satb?

> src/java.base/share/man/java.md line 2903:
> 
>> 2901:     `passive`
>> 2902:     :   Stop the world GC only (either degenerated or full). This mode is
>> 2903:         diagnostic, and must be enabled via `-XX:+UnlockDiagnosticVMOptions`.
> 
> I don't think we add diagnostic options to the generic options list. These are not for end users, and we do not surface them unnecessarily.

Will remove

> src/java.base/share/man/java.md line 2923:
> 
>> 2921:     `aggressive`
>> 2922:     :   Run GC continuously, try to evacuate everything. This heuristics is
>> 2923:         diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.
> 
> Same here: diagnostic option.

Will remove

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PR Review Comment: https://git.openjdk.org/jdk/pull/26907#discussion_r2299318486
PR Review Comment: https://git.openjdk.org/jdk/pull/26907#discussion_r2299321044
PR Review Comment: https://git.openjdk.org/jdk/pull/26907#discussion_r2299321354