RFR: 8268406: Deallocate jmethodID native memory [v2]

[Coleen Phillimore]

On Tue, 17 Jun 2025 05:24:57 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

>> Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Fix formatting errors.
>
> src/hotspot/share/oops/jmethodIDTable.cpp line 126:
> 
>> 124: static bool needs_resize(Thread* current) {
>> 125:   return ((_jmethodID_counter > (_resize_load_trigger * table_size(current))) &&
>> 126:          !_jmethod_id_table->is_max_size_reached());
> 
> Should we not just have a separate jmethodID entry count variable we use here instead, that is incremented and decremented on insert and remove. Rather than using the next jmethodID counter which just grows monotonically regardless of any removals.

If we remove a jmethodID, we need to keep the number for it in case some JVMTI code still thinks that number is valid.  So we can't decrement the entry count.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25267#discussion_r2152136500