[crac] RFR: 8364554: [CRaC] Improve CRaC VM options' docs [v4]

[Radim Vansa]

On Fri, 8 Aug 2025 12:40:23 GMT, Timofei Pushkin <tpushkin at openjdk.org> wrote:

>> src/hotspot/share/runtime/arguments.cpp line 1:
>> 
>>> 1: /*
>> 
>> BTW maybe it is time to put expiration dates for all of CRaC's deprecated/obsoleted options? For each parsed argument there are linear searches through lists of special (deprecated/obsoleted/expired) and aliased flags `strcmp`-ing them which slows down argument parsing.
>> 
>> Since most of them have been deprecated since winter we can put 26 as the expiration version: it will be a year since the options were deprecated. For the ones deprecated/obsoleted today it can be 27.
>
> Ended up expiring everything since 26: the options added to special in this PR are diagnostic/experimental and not widely used, so this is in accordance with OpenJDK's recommendations.

Expiration by 26 is probably fine, but it seems that you're obsoleting retroactively? There is no 24-based version that would obsolete those, this will be ~25 and you're obsoleting on the spot. Except for `CRaCDoThrowCheckpointException` I would make these defunct (through expiration) only in 26.

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PR Review Comment: https://git.openjdk.org/crac/pull/256#discussion_r2263410675