RFR: 8274178: G1: Occupancy value in IHOP logging and JFR event is inaccurate [v6]

[Albert Mingkun Yang]

On Thu, 13 Nov 2025 11:15:59 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Hi all,
>> 
>>   please review this change that modifies heap occupancy reporting for IHOP to use the actual occupancy value the IHOP calculation actually uses.
>> 
>> I.e. previously IHOP logging used to report `G1CollectedHeap::used()` as occupancy (which is correct at a general level), but for IHOP/marking that value is not interesting, but the "occupancy" value used for comparing against the current heap occupancy threshold.
>> 
>> Testing: tier1-3, GHA
>> 
>> Thomas
>
> Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:
> 
>   * some additional documentation around `G1CollectedHeap::non_young_occupancy_after_allocation`

Marked as reviewed by ayang (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/28175#pullrequestreview-3459265713