RFR: 8301341: LinkedTransferQueue does not respect timeout for poll() [v9]

[Viktor Klang]

On Fri, 21 Jul 2023 12:31:07 GMT, Doug Lea <dl at openjdk.org> wrote:

>> This update addresses performance issues across both LinkedTransferQueue and SynchronousQueue by creating a common basis for implementation across them (mainly in LinkedTransferQueue).  Pasting from internal doc summary of changes:
>>      * * Class DualNode replaces Qnode, with fields and methods
>>      *   that apply to any match-based dual data structure, and now
>>      *   usable in other j.u.c classes. in particular, SynchronousQueue.
>>      * * Blocking control (in class DualNode) accommodates
>>      *   VirtualThreads and (perhaps virtualized) uniprocessors.
>>      * * All fields of this class (LinkedTransferQueue) are
>>      *   default-initializable (to null), allowing further extension
>>      *   (in particular, SynchronousQueue.Transferer)
>>      * * Head and tail fields are lazily initialized rather than set
>>      *   to a dummy node, while also reducing retries under heavy
>>      *   contention and misorderings, and relaxing some accesses,
>>      *   requiring accommodation in many places (as well as
>>      *   adjustments in WhiteBox tests).
>
> Doug Lea has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Address review comments

src/java.base/share/classes/java/util/concurrent/LinkedTransferQueue.java line 1584:

> 1582:                 if (isData) {
> 1583:                     action.accept((E) item);
> 1584:                     pred = p; p = q; continue;

@DougLea These three statements deserve their own lines, I'd say. :)

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PR Review Comment: https://git.openjdk.org/jdk/pull/14317#discussion_r1270715057