OA38295: HIGH PAGING OF HIPERSPACE PAGES

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• At z/OS 1.12 hiperspace pages may be paged to AUX instead of
  staying in REAL storage on a SWRITE.  RSM issues a SYSEVENT
  DIRECTPO to determine if the pages should go to REAL or
  AUXILIARY storage.  IRARMFP1, entry point IRARMF56, will send to
  REAL if RCEAFC is twice as much as RCEAFCOK, which is too
  restrictive.  This causes excessive hiperspace paging to AUX.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of z/OS 1.12 (HBB7770) and         *
  *                 above.                                       *
  ****************************************************************
  * PROBLEM DESCRIPTION: Excessive hiperspace paging to AUX can  *
  *                      occur on z/OS 1.12 because hiperspace   *
  *                      pages may be paged to AUX instead of    *
  *                      staying in REAL storage on a SWRITE.    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  RSM issues a SYSEVENT DIRECTPO to determine if a hiperspace
  page should be sent to auxiliary storage or stay in real
  storage.  At z/OS 1.12, entry point IRARMF56 in IRARMFP1, will
  only direct that the pages stay in real storage if RCEAFC is
  twice as much as RCEAFCOK, which is too restrictive and can
  cause excessive hiperspace paging to AUX.
  

Problem conclusion

• The check in IRARMFP1, entry point IRARMF56, to determine where
  a hiperspace page should be sent has been updated to no longer
  just base the decision on the RCEAFC field.  Pages will now also
  be directed to real storage when the MCVUIC3 and MCVUIC4 fields
  contain more than 10% of the real storage (RCEPOOL).
  

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:

  UA64117 UA64118

Modules/Macros

• IRARMFP1
  

Fix information

• Fixed component name

  SRM - SYS RSRCE

• Fixed component ID

  5752SC1CX

Applicable component levels

• R770 PSY UA64117

     UP12/02/22 P F202

• R780 PSY UA64118

     UP12/02/22 P F202

Fix is available

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