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  1. JDK
  2. JDK-8224584

Shenandoah: Eliminate forwarding pointer word

    Details

    • Type: Enhancement
    • Status: Resolved
    • Priority: P3
    • Resolution: Fixed
    • Affects Version/s: 8-shenandoah, 11-shenandoah, 13
    • Fix Version/s: 13
    • Component/s: hotspot
    • Subcomponent:
      gc
    • Resolved In Build:
      b23
    • CPU:
      generic
    • OS:
      generic

      Backports

        Description

        Shenandoah uses an extra word per object to store the forwarding pointer of an object in support of concurrent evacuation. With the arrival of load reference barriers, it is possible to store the forwarding pointer in the then-unused memory of from-space-copy of an object instead, for example use the from-space-mark-word and encode the forwarding pointer there. This allows to eliminate the extra forwarding pointer word, and thus reduces memory footprint, and gives the GC and application more headroom to work with.

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                • Assignee:
                  rkennke Roman Kennke
                  Reporter:
                  rkennke Roman Kennke
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                  • Created:
                    Updated:
                    Resolved: