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  1. JDK
  2. JDK-8129886

Test TestPromotionToSurvivor fails with jimage refresh

    Details

    • Subcomponent:
      gc
    • Introduced In Version:
      9

      Description

      jimage seems to add just enough instances to the heap to cross the test boundary.
      jimage change alone doesn't make the test to fails. But applied on top of 24-June-2015 hs-rt, it fails.

      For now we are ignoring it (as suggested by test owner).

      Motivation:

      The test wants to find out whether the GC properly aligns objects in the
      survivor space by checking whether a fixed amount of objects with a
      given size gets "expanded" to the right amount of memory after it has
      been copied with alignment.

      This is problematic because if somebody else than the test allocated
      some memory on the Java heap inbetween, then it fails. There is this 1M
      slack to avoid that. That slack has basically been sized to "work".
      There is also some detection if some other threads, like an attached VM
      agent, allocates memory inbetween, but that one is not particularly
      good. (E.g. in https://bugs.openjdk.java.net/browse/JDK-8081688 it very
      often detects this situation wrongly, making the test pass without
      checking anything).

      So if for some reason with the change you have the VM allocates more
      Java objects during the test period (like if some background thread is
      still busy loading non-essential classes when the test is running, and
      this additional memory use is intentional/known/okay), the test breaks.

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              • Assignee:
                Unassigned
                Reporter:
                jfdenise Jean-Francois Denise (Inactive)
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                • Created:
                  Updated:
                  Resolved: