IZ67874: JAVA JIT COMPILATION THREAD NOT RELEASING VM CLASS TABLE LOCK CAUSING APPLICATION TO HANG.

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • Error Message: The application hangs in a random or intermittent
    manner while under heavy load with frequent GC cycles.
    .
    Stack Trace: N/A
    .
    The javacore shows:
    
    1) That the VM class table lock is owned by the JIT Compilation
    Thread and a number of other threads are waiting to obtain the
    lock.
    
    2LKREGMON          VM class table lock (0x...): Flat locked by
     "JIT Compilation Thread" (0x...), entry count 1
    3LKWAITERQ            Waiting to enter:
    3LKWAITER                "ThreadName" (0x...)
    
    2) The JIT-CompilationQueueMonitor lock is unowned.
    
    2LKREGMON          JIT-CompilationQueueMonitor lock (0x...):
     <unowned>
    3LKNOTIFYQ            Waiting to be notified:
    3LKWAITNOTIFY            "JIT Compilation Thread" (0x...)
    
    KEYWORDS
    Deadlock hang
    

Local fix

  • This problem can be avoided by using the -Xjit:disableCHTable
    option. Note however that this option may incur a slight
    performance impact.
    

Problem summary

  • When a JIT compilation is abandoned while holding the VM class
    table lock, the JIT will never release the lock resulting in any
    future class load operations to hang waiting to obtain the VM
    class table lock.
    

Problem conclusion

  • This defect will be fixed in:
    5.0.0 SR12
    .
    The JIT was modified so that the VM class table lock will be
    released when a compilation is abandoned.
    .
    To obtain the fix:
    Install build 20100126 or later
    

Temporary fix

Comments

APAR Information

  • APAR number

    IZ67874

  • Reported component name

    JAVA 5 JIT

  • Reported component ID

    620500124

  • Reported release

    500

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2010-01-15

  • Closed date

    2010-02-24

  • Last modified date

    2010-07-22

  • APAR is sysrouted FROM one or more of the following:

    IZ66183

  • APAR is sysrouted TO one or more of the following:

    PM10711

Fix information

  • Fixed component name

    JAVA 5 JIT

  • Fixed component ID

    620500124

Applicable component levels

  • R500 PSN

       UP



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Document information


More support for:

Runtimes for Java Technology
Just In Time (JIT) Compiler

Software version:

5.0

Reference #:

IZ67874

Modified date:

2010-07-22

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