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  1. JDK
  2. JDK-8329784

Run MaxMetaspaceSizeTest.java with -Xshare:off

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Details

    • Bug
    • Resolution: Fixed
    • P4
    • 23
    • None
    • hotspot
    • b18

    Description

      test/hotspot/jtreg/runtime/Metaspace/MaxMetaspaceSizeTest.java runs with MaxMetaspaceSize=4K and expects to get an OOM

       ProcessBuilder pb = ProcessTools.createLimitedTestJavaProcessBuilder(
                  "-Xmx1g",
                  "-XX:MaxMetaspaceSize=4K",
                  "-XX:+UseCompressedClassPointers",
                  "-XX:CompressedClassSpaceSize=1g",
                  "--version");

      However, if CDS is enabled, it's possible to run the VM with a very small MaxMetaspaceSize without getting an OOM.

      We should run with -Xshare:off to guarantee that lots of class metadata objects are allocated as classes are being parsed.

      Also, this comment is wrong and should be deleted:

      https://github.com/openjdk/jdk/blob/4a11db8b606f2b10f48f0b45335b661fe3095fc4/test/hotspot/jtreg/runtime/Metaspace/MaxMetaspaceSizeTest.java#L45

      // We do not explicitly limit MaxMetaspaceSize to a lower minimum. User can get as low as he wants.

      We actually override the user setting here:

      https://github.com/openjdk/jdk/blob/4a11db8b606f2b10f48f0b45335b661fe3095fc4/src/hotspot/share/memory/metaspace.cpp#L647

      MaxMetaspaceSize = MAX2(MaxMetaspaceSize, commit_alignment());

      On my Linux/x64, MaxMetaspaceSize is set to at least 64K.

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              iklam Ioi Lam
              iklam Ioi Lam
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                Updated:
                Resolved: