RFR: 8367485: os::physical_memory is broken in 32-bit JVMs when running on 64-bit OSes [v9]

[Stefan Karlsson]

On Fri, 19 Sep 2025 08:01:44 GMT, Anton Artemov <duke at openjdk.org> wrote:

>> Hi, please consider the following changes:
>> 
>> In this PR we address the overflow issue in `os::physical_memory()` on Linux, which can occur when running a 32-bit JVM on a 64-bit machine, introduced by https://bugs.openjdk.org/browse/JDK-8357086. The problem is that the product of _SC_PHYS_PAGES and _SC_PAGESIZE can overflow according to the documentation. 
>> 
>> The issue is addressed by changing the output type of all related functions to `uint64_t`.
>> 
>> Tested in tiers 1 - 5.
>
> Anton Artemov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8367485: Alignment of vars in os_windows.cpp

Marked as reviewed by stefank (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/27335#pullrequestreview-3243757035