RFR: 8357086: os::xxx functions returning memory size should return size_t [v7]

[Anton Artemov]

On Thu, 12 Jun 2025 08:43:47 GMT, Anton Artemov <duke at openjdk.org> wrote:

>> Hi,
>> 
>> in this PR the output value type for functions which return memory are changed, namely:
>> 
>> 
>> static julong available_memory(); --> static size_t available_memory();
>> static julong used_memory(); --> static size_t used_memory();
>> static julong free_memory(); --> static size_t free_memory(); 
>> static jlong total_swap_space(); --> static ssize_t total_swap_space();
>> static jlong free_swap_space(); --> static ssize_t free_swap_space(); 
>> static julong physical_memory(); --> static size_t physical_memory(); 
>> 
>> 
>> The changes are done so that the other parts of the code have minimal impact. 
>> Tested in GHA and Tiers 1-4.
>
> Anton Artemov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8357086: Added missed casts.

I think we could extend the usage of a large number `static_cast<size_t>(-1)` for indication of error to other platforms similarly to how it is done in `os_linux.cpp`.

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PR Comment: https://git.openjdk.org/jdk/pull/25450#issuecomment-2965706974