RFR: 8343704: Bad GC parallelism with processing Cleaner queues [v6]

[Aleksey Shipilev]

On Thu, 14 Nov 2024 11:50:31 GMT, Oli Gillespie <ogillespie at openjdk.org> wrote:

>> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Reimplement with segmented linked list of arrays
>
> src/java.base/share/classes/jdk/internal/ref/CleanerImpl.java line 310:
> 
>> 308:                Node newHead = head.next;
>> 309:                newHead.prev = null;
>> 310:                head = newHead;
> 
> Does this allow removing the final head node when the list is empty? Seems we need to avoid that (`if (head.size == 0 && head.next != null)`?.

Good spot. Fixed it exactly like that. Managed to create a direct unit test that captures it, among other things.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22043#discussion_r1842209760