RFR: 8305819: LogConfigurationTest intermittently fails on AArch64

[Andrew Haley]

On Fri, 21 Apr 2023 02:51:38 GMT, gaogao-mem <duke at openjdk.org> wrote:

>> src/hotspot/share/logging/logOutputList.cpp line 130:
>> 
>>> 128:   }
>>> 129: 
>>> 130:   OrderAccess::storestore();
>> 
>> Suggestion:
>> 
>>   OrderAccess::release();
>> 
>> I don't think it'd hurt performance significantly, and is safer and easier to reason about.
>
> Thanks for your suggestion! The performance issue I mentioned earlier was due to adding OrderAccess::loadload while reading the list, but after researching some information for memory barrier, it was found to be unnecessary.

Atomic access is unnecessary when reading the list? I'd like to know the reasoning behind that.
I guess you could argue that dependency would save you on the read side, but I'd like to see and understand the code. It's very risky to depend on that,

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PR Review Comment: https://git.openjdk.org/jdk/pull/13421#discussion_r1173481778