On Tue, 18 Mar 2025 09:11:00 GMT, Dmitry Chuyko <dchu...@openjdk.org> wrote:
>> Please review a tiny fix in the ForkJoinPool. Since JDK 9 (JDK-8134852 [1]) >> in one case when TC subfield in ctl field is decremented, the applied >> masking (UMASK, upper bits) may not preserve neighbor RC subfield sometimes. >> In JDKs prior to 19 FJP may stop executing tasks, which requires a long >> running application restart [2]. Since 19 it is even harder to reproduce >> because of the separate parallelism field. >> >> The fix is to replace 'UMASK & (c - TC_UNIT)' with '(c & RC_MASK) | ((c - >> TC_UNIT) & TC_MASK)' which preserves the RC part of the compareAndSetCtl() >> candidate argument. On 17u and 11u that repairs known tests and >> applications. This PR is for the mainline, and I intend to backport it to >> 21u, 17u and 11u. >> >> [1] https://bugs.openjdk.org/browse/JDK-8134852 >> [2] https://bugs.openjdk.org/browse/JDK-8330017 > > Dmitry Chuyko has updated the pull request incrementally with one additional > commit since the last revision: > > Aligned with JDK-8319447 Marked as reviewed by alanb (Reviewer). ------------- PR Review: https://git.openjdk.org/jdk/pull/24034#pullrequestreview-2698006904
