OA44183: EXCESSIVE CPU CONSUMPTION IN *MASTER* DUE TO IAXUR RUNNING FOR PAGEABLE LARGE REFORM.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• If a pageable large frame is broken up into 4K frames, some of
  those 4K frames can be used for long-term fixed frames owned by
  nonswappable address spaces.  If this happens and a later reform
  is attempted, this frame cannot be reformed, and IAXUR will
  reschedule itself every 5 seconds indefinitely.
  IAXUR should recognize this situation and stop attempting to
  reform nonreformable large pages.
  

Local fix

• Apply PTF when available.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of JBB778H and above.                  *
  ****************************************************************
  * PROBLEM DESCRIPTION: High CPU in *MASTER* address space      *
  *                      caused by IAXUR free frame SRB          *
  *                      continuously rescheduling itself        *
  *                      attempting to reform pageable large     *
  *                      frames.                                 *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Pageable large frames were broken up to satisfy real storage
  demand for 4k frames.  Later on, the system demand for 4k frames
  declined and these pages were scheduled to be reformed into
  pageable large frames.  Some of the frames scheduled for reform
  were fixed, requiring IAXUR to be scheduled to reclaim the
  allocated frames.  The address spaces that owned these frames
  were nonswappable and IAXUR scheduled itself to try again in 5
  seconds.  These frames remained fixed for a long period of time
  and IAXUR continuously rescheduled itself, causing high CPU in
  *MASTER* each time it ran.
  

Problem conclusion

• Module IAXUR is changed to not reschedule itself when reforming
  pageable 1meg pages if the frames are fixed and the address
  spaces are nonswappable.
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

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

  UA72880 UA72881

Modules/Macros

• IAXUR
  

Fix information

• Fixed component name

  RSM - REAL STOR

• Fixed component ID

  5752SC1CR

Applicable component levels

• R78H PSY UA72881

     UP14/04/02 P F404 Ž

• R790 PSY UA72880

     UP14/04/02 P F404 Ž

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.