RFR: 8367485: os::physical_memory is broken in 32-bit JVMs when running on 64-bit OSes [v13]

[Anton Artemov]

On Thu, 25 Sep 2025 09:55:56 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> Anton Artemov has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - 8367485: Fixed new line after typedef.
>>  - 8367485: Fixed comment in global definitions.
>
> src/hotspot/share/utilities/globalDefinitions.hpp line 422:
> 
>> 420: 
>> 421: //----------------------------------------------------------------------------------------------------
>> 422: // Type defenition for memory functions
> 
> There's a typo here defenition > definition.  With that said, this comment mimics the comments for the sections above and below:
> 
> // VM type definitions
> // Java type definitions
> 
> but we don't need a new section, so I think we should not follow those patterns. Instead it would be good to have a motivation for having this typedef. Something that explains that the amount of physical memory doesn't necessarily fit in a 32-bit size_t for 32-bit JVMs and that we have this typedef to mark the places where we have to deal with that quirk as long as we support 32-bit JVMs.

Thanks, I addressed this by adding an extended comment. No new section added as suggested.

> src/hotspot/share/utilities/globalDefinitions.hpp line 423:
> 
>> 421: //----------------------------------------------------------------------------------------------------
>> 422: // Type defenition for memory functions
>> 423: typedef uint64_t physical_memory_size_type;
> 
> When adding code make sure have a blank line between the new code and the surrounding code.

Line added.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27335#discussion_r2378568022
PR Review Comment: https://git.openjdk.org/jdk/pull/27335#discussion_r2378569525