RFR: 8306738: Select num workers for safepoint ParallelCleanupTask [v4]

[Coleen Phillimore]

On Mon, 8 May 2023 10:12:23 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

>> Select num workers for safepoint ParallelCleanupTask to be at most the number of parallel cleanup tasks `SAFEPOINT_CLEANUP_NUM_TASKS`
>> 
>> Unsure if `WorkerThreads::max_workers()` is more correct than `WorkerThreads::created_workers()` or `WorkerThreads::active_workers()`. 
>> 
>> Tested tier1-3 Oracle platforms.
>
> Axel Boldt-Christmas has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Aleksey Shipilëv feedback: readability of conditions

The new function rehash_table_expects... looks fine in this change, and thank you for the comments.  I think your code pushes the motivation for a superclass to have these duplicated functions over the top.  I'll file another RFE for that for later.  Thank you @shipilev for doing the performance measurements.

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Marked as reviewed by coleenp (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/13616#pullrequestreview-1417023953