[crac] RFR: 8377173: [CRaC] Don't set direct_map=true on checkpoint [v2]

[Timofei Pushkin]

On Thu, 5 Feb 2026 11:03:37 GMT, Radim Vansa <rvansa at openjdk.org> wrote:

>> src/hotspot/share/runtime/crac_engine.cpp line 185:
>> 
>>> 183:   }
>>> 184: 
>>> 185:   if (for_restore && api.can_configure(conf, DIRECT_MAP)) {
>> 
>> We have `CStringSet keys` below that stores all options parsed from `CRaCEngineOptions`. We could move this after the `CRaCEngineOptions` processing to apply only if `DIRECT_MAP` was not in `CRaCEngineOptions`. This way we can avoid providing the option twice — can help against warnings if the engine also performs duplication checking internally.
>
> I've moved this, though the change is a bit heavier (can't use the early exit). And I am not even sure if the engine ought to check this - it should be OK to override the configuration couple of times.
> 
> I'd be happy to revert the last commit if you see it the same way.

I expected that the early return would need to go, looks fine by me. Just suggested this to omit doing redundant work.

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PR Review Comment: https://git.openjdk.org/crac/pull/292#discussion_r2768530287