PK63830: SLOW STORAGE GROWTH OF DUSAS IN SUBPOOL 241 KEY 6

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Slow storage growth in subpool 241 key 6 with DUSA control
  blocks of size x'7000'.  The DUSA is an expansion of the DUCB.
  In this case,  mini-DUCBs are being used.  CTRACE is set with
  option SOCKET, causing the mini-DUCBs to be expanded to cut the
  CTRACE record (out of EZBCTRCD).  This DUSA should be freed when
  the DUCB is destroyed.  In this cause, the DUCB has abended.
  The recovery routine does not free up the DUSA causing the
  storage growth.
  .
  KEYWORDS: sp241 k6 AB222 ABEND222 ABEND 222 EZBUDWRT
  .
  VERIFICATION STEPS:
  DUSA will also contain an eye catcher of EZBCTRCD.
  .
  You may also be able to find a DUCB on the available queue that
  has a non zero dusa_nextDUSA.  This DUCB will have a calling
  sequence of:
  1000084B 15105A78 14E72400 14E725A0 00F82680 04D2 EDAWCP5
  00000000
  RSA  14E72A68  Prev 00000000  Next 14E72B08  Mod EZBITDRC
  RSA* 14E72B10  Prev 14E72A68  Next 00000000  Mod EZBITKRA
  RSA* 0E692C40  Prev 14E73960  Next 0E692F88  Mod EZBCTRCD
  .
  EZBITDRC indicates the TCPIP recovery routing got control
  .
  This problem has also been seen with DUSA growth showing
  module EZBUDWRT.  The non-retryable abend was an ABEND222.
  In addition to the storage growth showing DUSA and EZBUDWRT,
  DUCBs with the following calling sequence may be found in
  the IP TCPIPCS DUAF report.
  20000801 29ABD828 28A4CC00 28A4CDA0 00EADF80 02F3 JOBNAME
                                                       00222000 Ab
  RSA  28A4D258  Prev 00000000  Next 28A4D2F8  Mod EZBPFVNR
  RSA* 28A4D300  Prev 28A4D258  Next 00000000  Mod EZBITKRA
  RSA* 201D2C40  Prev 28A4D258  Next 201D4548  Mod EZBUDWRT
  .
  

Local fix

• Turn off CTRACE option SOCKET.  This will cut down on the number
  of times a DUSA expansion is needed.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of the IBM Communications Server   *
  *                 for z/OS Version 1 Release 9 IP              *
  ****************************************************************
  * PROBLEM DESCRIPTION: Storage growth in SP241 K6 related to   *
  *                      DUSA expansion areas not being released *
  *                      following a non-retryable abend.        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Storage growth in subpool 241 key 6 when DUSA expansion areas
  are not released following a non-retryable abend.
  A dispatchable unit control block (DUCB) will be assigned to
  a unit of work entering the main TCP/IP points of entry.  The
  DUCB has a DUSA associated with it which represents the dynamic
  storage area.
  The DUSA expansion area is allocated when the dispatchable unit
  requires additional dynamic area and the currently associated
  DUSA has insufficient space.  The expansion area will contain
  the DUSA eye-catcher and will be chained on the preceding
  DUSA.  When the dispatchable unit returns out of TCP/IP code
  the expanded DUSA areas are released.
  In the event the dispatchable unit terminates with a non-
  retryable abend the DUSA expansion area(s) will not be
  released.
  +-------------------------------------------------------------+
  + Please check our Communications Server for OS/390 homepages +
  + for common networking tips and fixes.  The URL for these    +
  + homepages can be found in Informational APAR II11334.       +
  +-------------------------------------------------------------+
  

Problem conclusion

• EZBITSCU has been amended to release the DUSA expansion area(s)
  before returning abended DUCBs to the cache queue.
  
  * Cross Reference between External and Internal Names
  

Temporary fix

Comments

APAR Information

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

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

  UK35548 PK68004 PK93317

Modules/Macros

• EZBITSCU
  

Fix information

• Fixed component name

  TCP/IP V3 MVS

• Fixed component ID

  5655HAL00

Applicable component levels

• R190 PSY UK35548

     UP08/05/03 P F805

Fix is available

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