Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-8067331

Zero: Atomic::xchg and Atomic::xchg_ptr need full memory barrier

    XMLWordPrintable

Details

    • Bug
    • Resolution: Fixed
    • P4
    • 9
    • 9
    • hotspot
    • b48
    • generic
    • generic

    Backports

      Description

        Some code in hotspot depends on Atomic::xchg to be a full memory barrier. Example:


        void Parker::park(bool isAbsolute, jlong time) {
          // Ideally we'd do something useful while spinning, such
          // as calling unpackTime().

          // Optional fast-path check:
          // Return immediately if a permit is available.
          // We depend on Atomic::xchg() having full barrier semantics
          // since we are doing a lock-free update to _counter.
          if (Atomic::xchg(0, &_counter) > 0) return;


        However, the Zero implementation is not implemented as a full memory barrier.

        Attachments

          Issue Links

            backported by

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8073841 Zero: Atomic::xchg and Atomic::xchg_ptr need full memory barrier

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8077437 Zero: Atomic::xchg and Atomic::xchg_ptr need full memory barrier

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8083193 Zero: Atomic::xchg and Atomic::xchg_ptr need full memory barrier

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8086420 Zero: Atomic::xchg and Atomic::xchg_ptr need full memory barrier

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8137583 Zero: Atomic::xchg and Atomic::xchg_ptr need full memory barrier

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Activity

              People

                sgehwolf Severin Gehwolf
                sgehwolf Severin Gehwolf
                Votes:
                0 Vote for this issue
                Watchers:
                4 Start watching this issue

                Dates

                  Created:
                  Updated:
                  Resolved: