RFR: 8355627: Don't use ThreadCritical for EventLog list [v2]

[Coleen Phillimore]

On Wed, 30 Apr 2025 20:16:18 GMT, Zhengyu Gu <zgu at openjdk.org> wrote:

>> Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Use CAS loop instead of lockFreeStack.
>
> src/hotspot/share/utilities/events.cpp line 58:
> 
>> 56:     old_head = Atomic::load(&Events::_logs);
>> 57:     _next = old_head;
>> 58:   } while (Atomic::cmpxchg(&Events::_logs, old_head, this, memory_order_relaxed) != old_head);
> 
> I don't think it is safe to use `memory_order_relaxed` order if events are added after JVM enters multi-thread mode.

Thanks for this. I didn't know why Aleksey suggested it.  I'll remove it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24954#discussion_r2069401517