RFR: 8357473: Compilation spike leaves many CompileTasks in free list [v6]

[Aleksey Shipilev]

On Tue, 8 Jul 2025 08:59:53 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> See bug for more discussion.
>> 
>> This PR implements the "all the way" solution by removing the free list completely. It complements https://github.com/openjdk/jdk/pull/25364, and can go either first, or second. We will remerge the other one once either integrates.
>> 
>> Additional testing:
>>  - [x] Linux x86_64 server fastdebug, `compiler`
>>  - [x] Linux AArch64 server fastdebug, `all`
>
> Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 11 commits:
> 
>  - Task count atomic can be relaxed
>  - Minor touchup in ~CompileTask
>  - Purge CompileTaskAlloc_lock completely
>  - Merge branch 'master' into JDK-8357473-compile-task-free-list
>  - Merge branch 'master' into JDK-8357473-compile-task-free-list
>  - Merge branch 'master' into JDK-8357473-compile-task-free-list
>  - Merge branch 'master' into JDK-8357473-compile-task-free-list
>  - Merge branch 'master' into JDK-8357473-compile-task-free-list
>  - Also free the lock!
>  - Comments and indenting
>  - ... and 1 more: https://git.openjdk.org/jdk/compare/7b255b8a...684f83b7

Also realized the Atomic can be relaxed, since nothing rides on its memory consistency effects. I am retesting to make sure.

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PR Comment: https://git.openjdk.org/jdk/pull/25409#issuecomment-3048024663