On Thu, 3 Jul 2025 00:52:56 GMT, Zhengyu Gu <z...@openjdk.org> wrote:
>>> I don't think throwing OOM, from gc's perspective, is an "error".
>>
>> Nevermind; I just obey the statement in methods
>> `MemAllocator::Allocation::check_out_of_memory` and
>> `Universe::out_of_memory_error_java_heap`.
>
> Returning `null` outside of a safe point does have unexpected negative
> effects. e.g. `HeapDumpOnOutOfMemoryError` may not get good heap dump, as
> other threads can come in and run additional GCs, then the heap dump may
> contain confusingly little live data.
>
> I wonder if you can improve this situtation.
Let me try to rephrase your concern to ensure that I understand you correctly
-- after `_gc_overhead_counter >= GCOverheadLimitThreshold`, it's possible that
another GC is triggered, which reclaims much free memory, and resets
`_gc_overhead_counter` to zero. Then, `HeapDumpOnOutOfMemoryError` will not be
able to get the intended heap snapshot.
Is my understanding correct?
(Seems that baseline resets the condition and can encounter the same problem as
well.)
if (limit_exceeded && softrefs_clear) {
*gc_overhead_limit_was_exceeded = true;
size_policy()->set_gc_overhead_limit_exceeded(false);
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/25000#discussion_r2188604729
