RFR: 8367413: Use size_t instead of julong in runtime/arguments.cpp [v2]

[Albert Mingkun Yang]

On Thu, 11 Sep 2025 13:42:33 GMT, Joel Sikström <jsikstro at openjdk.org> wrote:

>> Hello,
>> 
>> There are several unnecessary uses of the julong type in arguments.cpp that could use size_t instead to fit in better with surrounding code. Almost all flags that are read in arguments.cpp are size_t, and the os functions it interacts with were changed from julong to size_t in [JDK-8357086](https://bugs.openjdk.org/browse/JDK-8357086) or are already taking in size_t.
>> 
>> The main usage of julong in runtime/arguments.cpp is in Arguments::set_heap_size() and Arguments::set_aggressive_heap_flags(), where there are a lot of casts from julong types to size_t which could be removed with this change.
>> 
>> Testing:
>> * Running through Oracle's tier1-3 on all Oracle supported platforms
>
> Joel Sikström has updated the pull request incrementally with one additional commit since the last revision:
> 
>   size_t casts for 32-bit part of test_arguments.cpp

src/hotspot/share/runtime/arguments.cpp line 1526:

> 1524:       FLAG_SET_ERGO(MaxRAM, (uint64_t)phys_mem);
> 1525:     } else {
> 1526:       phys_mem = (size_t)MaxRAM;

Pre-existing: I wonder if this should be `MIN2(MaxRAM, SIZE_MAX)` to handle 32-bit systems.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27224#discussion_r2340949951