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  1. JDK
  2. JDK-8218156

"jcmd VM.metaspace basic" misreports free chunk space

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    • Subcomponent:
    • Introduced In Version:
      11
    • Resolved In Build:
      b07

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        Description

        "VM.metaspace basic" is a variant of the "big" VM.metaspace report. It misprints the sizes of the chunk free lists:

        thomas@mainframe:/shared/projects/openjdk$ jjjcmd stuefe VM.metaspace basic
        12967:

        Usage:
          Non-class: 12,83 MB capacity, 11,26 MB ( 88%) used, 1,54 MB ( 12%) free+waste, 35,69 KB ( <1%) overhead.
              Class: 1,37 MB capacity, 1,08 MB ( 79%) used, 287,62 KB ( 20%) free+waste, 12,94 KB ( <1%) overhead.
               Both: 14,20 MB capacity, 12,34 MB ( 87%) used, 1,82 MB ( 13%) free+waste, 48,62 KB ( <1%) overhead.

        Virtual space:
          Non-class space: 16,00 MB reserved, 15,25 MB ( 95%) committed
              Class space: 1,00 GB reserved, 99,10 MB ( 10%) committed
                     Both: 1,02 GB reserved, 114,35 MB ( 11%) committed

        Chunk freelists:
           Non-Class: 280,75 KB <<<<<<
               Class: 12,21 MB <<<<<<
                Both: 12,48 MB <<<<<<

        Compare with the non-basic command:

        thomas@mainframe:/shared/projects/openjdk$ jjjcmd stuefe VM.metaspace
        12967:

        Total Usage ( 175 loaders):

          Non-Class: 571 chunks, 12,83 MB capacity, 11,26 MB ( 88%) used, 1,54 MB ( 12%) free, 480 bytes ( <1%) waste, 35,69 KB ( <1%) overhead, deallocated: 315 blocks with 75,33 KB
              Class: 207 chunks, 1,37 MB capacity, 1,08 MB ( 79%) used, 287,62 KB ( 20%) free, 0 bytes ( 0%) waste, 12,94 KB ( <1%) overhead, deallocated: 31 blocks with 11,12 KB
               Both: 778 chunks, 14,20 MB capacity, 12,34 MB ( 87%) used, 1,82 MB ( 13%) free, 480 bytes ( <1%) waste, 48,62 KB ( <1%) overhead, deallocated: 346 blocks with 86,45 KB

        Virtual space:
          Non-class space: 16,00 MB reserved, 15,25 MB ( 95%) committed
              Class space: 1,00 GB reserved, 99,10 MB ( 10%) committed
                     Both: 1,02 GB reserved, 114,35 MB ( 11%) committed


        Chunk freelists:
           Non-Class:

         specialized chunks: 2, capacity 2,00 KB <<<<<<
               small chunks: 33, capacity 132,00 KB <<<<<<
              medium chunks: 33, capacity 2,06 MB <<<<<<
           humongous chunks: (none)
                      Total: 68, capacity=2,19 MB
               Class:

         specialized chunks: (none)
               small chunks: (none)
              medium chunks: 3125, capacity 97,66 MB
           humongous chunks: (none)
                      Total: 3125, capacity=97,66 MB

        Waste (percentages refer to total committed size 114,35 MB):
                      Committed unused: 304,00 KB ( <1%)
                Waste in chunks in use: 480 bytes ( <1%)
                 Free in chunks in use: 1,82 MB ( 2%)
             Overhead in chunks in use: 48,62 KB ( <1%)
                        In free chunks: 99,85 MB ( 87%)
        Deallocated from chunks in use: 86,45 KB ( <1%) (346 blocks)
                               -total-: 102,10 MB ( 89%)

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                • Assignee:
                  stuefe Thomas Stuefe
                  Reporter:
                  stuefe Thomas Stuefe
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                  • Created:
                    Updated:
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