RFR: 8306738: Select num workers for safepoint ParallelCleanupTask [v3]

[Coleen Phillimore]

On Wed, 3 May 2023 14:34:16 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:
> 
>   Add expected_num_workers

I think this looks fine from the symbol/string table perspective. This rehashing should never be done except in very exceptional circumstances.

> (Also the xxxTable code duplication is pretty atrocious)

Yes.  It is.

src/hotspot/share/runtime/safepoint.cpp line 550:

> 548:                    Universe::heap()->uses_stack_watermark_barrier()) {}
> 549: 
> 550:   uint expected_num_workers() const {

should this be 'static' for internal linkage?

-------------

Marked as reviewed by coleenp (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/13616#pullrequestreview-1413715025
PR Review Comment: https://git.openjdk.org/jdk/pull/13616#discussion_r1185383741