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  1. JDK
  2. JDK-8238687

Investigate memory uncommit during young collections in G1

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    • gc

    Description

      Currently G1 uncommits memory in the Remark pause only. It may be better to uncommit at other places (see JDK-8238686) when heap usage is actually low.

      Similar to expansion, G1 could regularly check whether the GCTimeRatio is low enough (e.g. < 1/2 GCTimeRatio) to warrant heap shrinking.

      Note that the amount of uncommit should be so that heap resizing activity during further operation is minimal.

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          Enhancement - null JDK-8247843 Reconsider G1 default GCTimeRatio value

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

          Bug - A problem which impairs or prevents the functions of the product. JDK-8244603 G1 incorrectly limiting young gen size when using the reserve can result in repeated full gcs

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

          Enhancement - null JDK-8248324 G1: Remove resizing during Remark

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

          Enhancement - null JDK-8243672 Short term pause time ratio calculation in G1 off

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

          Bug - A problem which impairs or prevents the functions of the product. JDK-8238686 G1 may waste lots of space or fail to uncommit when observing MinHeapFreeRatio during sizing after full gc

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

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              tschatzl Thomas Schatzl
              tschatzl Thomas Schatzl
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                Created:
                Updated: