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  1. JDK
  2. JDK-8080784

G1: jmap -heap reports the wrong number of regions

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    Details

    • Type: Backport
    • Status: Closed
    • Priority: P2
    • Resolution: Fixed
    • Affects Version/s: 8u45
    • Fix Version/s: 8u60
    • Component/s: hotspot
    • Subcomponent:
      gc
    • Resolved In Build:
      b18
    • Verification:
      Verified

      Description

      Running a 32bit JVM (HotSpot 8u45) on Linux 64 bit hardware jmap reports strange region information for G1. Xmx is set to 2G (which fits MaxHeapSize in the output below) but region count (almost 15k) and capacity is incorrect. Both these values are based on the length of the G1HeapRegionTable.

      Heap Configuration:
         MinHeapFreeRatio = 40
         MaxHeapFreeRatio = 70
         MaxHeapSize = 2147483648 (2048.0MB)
         NewSize = 1048576 (1.0MB)
         MaxNewSize = 428867584 (409.0MB)
         OldSize = 4194304 (4.0MB)
         NewRatio = 2
         SurvivorRatio = 8
         MetaspaceSize = 16777216 (16.0MB)
         CompressedClassSpaceSize = 1073741824 (1024.0MB)
         MaxMetaspaceSize = 4294963200 (4095.99609375MB)
         G1HeapRegionSize = 1048576 (1.0MB)

      Heap Usage:
      G1 Heap:
         regions = 14336
         capacity = 15032385536 (14336.0MB)
         used = 76347888 (72.81101989746094MB)
         free = 14956037648 (14263.188980102539MB)
         0.5078893687043872% used

      The bug was reported by Jakub Kubrynski on hotspot-gc-dev@openjdk.java.net: http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2015-May/013434.html

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              Assignee:
              sjohanss Stefan Johansson
              Reporter:
              jwilhelm Jesper Wilhelmsson
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                Updated:
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