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  1. JDK
  2. JDK-8065218

Move CMS-specific fields from Space to CompactibleFreeListSpace

    Details

    • Type: Enhancement
    • Status: Resolved
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: 9
    • Fix Version/s: 9
    • Component/s: hotspot
    • Labels:
    • Subcomponent:
      gc
    • Resolved In Build:
      b43

      Backports

        Description

        The member
          MemRegionClosure* _preconsumptionDirtyCardClosure;
        is used by CMS to get the young gen collector to update the mod union table
        The field is currently in the abstract base class Space which unfortunately causes the field to be present in all subclasses, including G1's HeapRegions.
        In order to allow for future addition of fields to HeapRegions without increasing the footprint we should move the CMS-specific field to CompactibleFreeListSpace.

        In order to avoid changing the callers of the code the accessor is made virtual in the Space class, this should not be a performance problem since the caller already contains several calls to other virtual functions.

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                • Assignee:
                  mgerdin Mikael Gerdin (Inactive)
                  Reporter:
                  mgerdin Mikael Gerdin (Inactive)
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                  • Created:
                    Updated:
                    Resolved: