PJ40619: DASD CU FALL OVER TEST INPUT LIST SHUTDOW

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APAR status

  • Closed as program error.

Error description

  • See Problem Summary.
    

Local fix

  • na
    

Problem summary

  • APAR NUMBER:  PJ40619
    PRODUCT:  z/TPF
    FUNCTIONAL AREA:  DASD
    SHIPPED IN PUT:  10
    
    ABSTRACT:
    Due to PJ32026, unplanned module down ECBs were stalled waiting
    for I/O after a control unit failure.
    
    PACKAGE CONTENTS:
    Source Segments:
    (C) base/rt/cyen.asm
    
    Object Only Binaries:
    None.
    
    Configuration Independent Binaries:
    (C) base/obj/cyen.o
    (C) base/load/CYEN.so
    
    Support Files:
    base/lst/cyen.lst
    base/lst/CYEN.map
    
    OTHER BINARIES TO BUILD: NO
    None.
    
    COMMENTS:
    In a base-only environment, unplanned module down calls CPAD
    with force, quiesce, and cleanup options to perform all module
    down tasks in one call. If the module being taken offline is
    the last module for that LSS, the cleanup option performs I/O
    to update the subsystem status table (SSST) header and cache
    fast write ID (CFWID) table. This cleanup I/O is done prior to
    purging the module queue for the module going offline. This
    means other ECBs relying on this module to complete I/O must
    wait for the cleanup I/O to finish before the module down ECB
    can purge the module queue and IOBs can be processed.
    
    If multiple module down conditions occur at the same time,
    there is a scenario where module down ECBs can become stalled
    waiting for I/O to complete. For example, an unplanned module
    down ECB is processing module A, is performing the cleanup
    tasks, and some of the I/O to update the CFWID table or SSST
    header is queued to module B. Module B goes offline and the
    unplanned module down ECB for module B also has to perform
    cleanup tasks. Because of record locking, the cleanup for
    module B can't proceed until the cleanup for module A finishes.
    However, one or more IOBs for module A's cleanup tasks are
    stalled on module B and will never finish. This will lead to an
    input list shutdown condition and an IPL would be required to
    clear the condition.
    

Problem conclusion

  • SOLUTION:
    Segment cyen.asm is updated after label CYEN01B to perform
    module down processing in two steps. First, CPAD is called with
    the force and quiesce to force the module down and purge the
    module queue. After that is complete and the module is marked
    offline, CPAD is called a second time to perform the cleanup
    tasks including any I/O to update the SSST header and CFWID
    table. As a result of this change, module down ECBs should no
    longer be stalled waiting for I/O to complete.
    
    COREQS: NO
    None.
    
    MIGRATION CONSIDERATIONS: NO
    None.
    
    BUILD COMMANDS AND INSTRUCTIONS: YES
    #maketpf commands for linux
    maketpf -f CYEN cyen.o
    maketpf CYEN link TPF_VERIFY_LINK_REFS=NO
    maketpf CYEN link
    
    UPDATED INFORMATION UNITS: NO
    None.
    
    See your IBM representative if you need additional information.
    
    DOWNLOAD INSTRUCTIONS:
    http://www.ibm.com/software/htp/tpf/maint/maintztpf.html
    
    APAR URL:
    http://www.ibm.com/software/htp/tpf/ztpfmaint/put10/PJ40619.htm
    

Temporary fix

Comments

APAR Information

  • APAR number

    PJ40619

  • Reported component name

    Z/TPF

  • Reported component ID

    5748T1501

  • Reported release

    110

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-10-11

  • Closed date

    2012-12-20

  • Last modified date

    2012-12-20

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

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

Fix information

  • Fixed component name

    Z/TPF

  • Fixed component ID

    5748T1501

Applicable component levels

  • R110 PSY UP

       110



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Document information


More support for:

TPF
z/TPF

Software version:

110

Reference #:

PJ40619

Modified date:

2012-12-20

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