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  1. JDK
  2. JDK-8212879

Make JVMTI TagMap table concurrent

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Details

    • Enhancement
    • Resolution: Fixed
    • P3
    • 16
    • 16
    • hotspot
    • b26

    Description

      And use WeakHandles to point to the elements so that hashing doesn't have to be redone for GC.

      If we use OopStorage via WeakHandles, the GC can walk the oops concurrently. The oops were stored directly because there were unexpected NULL entries when they were jweak. I don't see why this would be a problem, except that the hashcode would be broken in this case. Making them use oop->identity_hash() would fix this. Unfortunately, identity_hash is the only hashcode that makes sense for any sort of oop that can be stored in the table.

      This anomalous table and its handling by GC is a problem area.

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          relates to

          Bug - A problem which impairs or prevents the functions of the product. JDK-8256651 nsk_jvmti_aod_disableEvent{s}AndFinish should pass address of success

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

          Bug - A problem which impairs or prevents the functions of the product. JDK-8256688 Shenandoah: Lock rank inversion after JDK-8212879

          • P2 - Crashes, loss of data, severe memory leak.
          • Resolved

          Bug - A problem which impairs or prevents the functions of the product. JDK-6458402 3 jvmti tests fail with CMS and +ExplicitGCInvokesConcurrent

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

          Bug - A problem which impairs or prevents the functions of the product. JDK-8282459 Debug agent CLASS_UNLOAD event handling should attempt to deliver events on dedicated debug agent thread

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

          Enhancement - null JDK-8256072 Eliminate JVMTI tagmap rehashing

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

          Enhancement - null JDK-8256664 Shenandoah: Cleanup after JDK-8212879

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

          Enhancement - null JDK-8256813 Simplify WeakProcessor counting of OopStorage entries

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

          Enhancement - null JDK-8256814 WeakProcessorPhases may be redundant

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

          Enhancement - null JDK-8256825 Cleanup WeakProcessorPhaseTimes

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

          Enhancement - null JDK-8257676 Simplify WeakProcessorPhase

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

          Bug - A problem which impairs or prevents the functions of the product. JDK-8256811 Delayed/missed jdwp class unloading events

          • P3 - Major loss of function.
          • Resolved

          Bug - A problem which impairs or prevents the functions of the product. JDK-8256830 misc tests failed with "assert(env->is_enabled(JVMTI_EVENT_OBJECT_FREE)) failed: checking"

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

          Commit Commit openjdk/jdk/ba721f5f

          Review Review openjdk/jdk/967

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              coleenp Coleen Phillimore
              coleenp Coleen Phillimore
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                Created:
                Updated:
                Resolved: