RFR: 8269417: Minor clarification on NonblockingQueue utility [v2]

[Kim Barrett]

On Mon, 28 Jun 2021 18:17:34 GMT, Man Cao <manc at openjdk.org> wrote:

>> Hi,
>> 
>> Could you review this change mainly based on the comments in https://github.com/openjdk/jdk/pull/4379?
>> I also added an assertion to ensure and better understand why the Atomic::store() in append() is correct.
>> 
>> Stress tested with fastdebug build with:
>> $ make test TEST="gtest:NonblockingQueueTestBasics gtest:NonblockingQueueTest" GTEST="REPEAT=-1"
>
> Man Cao has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Clarify cmpxchg only fail due to try_pop.

Looks good.

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Marked as reviewed by kbarrett (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/4600