8351933: Inaccurate masking of TC subfield decrement in ForkJoinPool

[dchuyko]

This a backport of JDK-8351933 [0] (PR [1]) for 11u. At one of code paths the TC subfield of ctl field is decremented and the result is not masked correctly. The target code is in runWorker() instead of tryTrim()/awaitWork() and the surrounding code is different from the current master, as well as the original mask name. The core change is the same, candidate for CTL.compareAndSet is constructed using '(RC_MASK & c) | (TC_MASK & (c - TC_UNIT))' instead of '(UC_MASK & (c - TC_UNIT))' to correctly preserve the RC subfield.

[0] https://bugs.openjdk.org/browse/JDK-8351933
[1] openjdk/jdk#24034

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Progress

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• JDK-8351933 needs maintainer approval

Issue

• JDK-8351933: Inaccurate masking of TC subfield decrement in ForkJoinPool (Bug - P4)

Reviewers

• Paul Hohensee (@phohensee - Reviewer)

Reviewing

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[openjdk]

❗ This change is not yet ready to be integrated.
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[openjdk]

This backport pull request has now been updated with the original issue, but not the original commit. If you have the original commit hash, please update the pull request title with Backport <hash>.

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• 00: Full (5d0156c9)

[openjdk]

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