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  1. JDK
  2. JDK-8233439

G1 zero_filled optimization when committing CardCountsTable does not work

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    • Subcomponent:
      gc
    • Resolved In Build:
      b22

      Description

      When committing pages g1 has an optimization to re-use OS-level zero filling of newly committed pages.

      This current does not work properly for the G1RegionsSmallerThanCommitSizeMapper::commit() call, e.g. for the card counts table.

      A 4k page on x86 spans two (1M) regions; for the first one of that set the code correctly passes zero_filled == true to the on_commit handler, but the second does not - which means that useless work is done.

      This impacts startup time slightly

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              • Assignee:
                sjohanss Stefan Johansson
                Reporter:
                tschatzl Thomas Schatzl
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