II12616: ABEND878 ABEND80A RC10 FOR SYSTEM REGION AREA INFORMATION IN ADDITION TO DEBUG INFO APAR II05506

APAR status

• Closed as canceled.

Error description

• ***************************************************************
  *                                                             *
  *  IMPORTANT information regarding the System Region area:    *
  *                                                             *
  * The following is from the MVS Initialization and Tuning     *
  * Guide:                                                      *
  *                                                             *
  * System Region                                               *
  * -------------                                               *
  * This area is reserved for GETMAINs by all system functions  *
  * (for example, ERPs) running under the region control task.  *
  * It comprises 16K (except in the master scheduler address    *
  * space, in which it has a 200K maximum) of each private area *
  * immediately above the PSA. V=V region space allocated to    *
  * user jobs is allocated upwards from the top of this area.   *
  * This area is pageable and exists for the life of each       *
  * address space.                                              *
  *                                                             *
  * In some cases, an ABEND878 or ABEND80A RC10 dump will show  *
  * a getmain failure for below the line low private storage    *
  * even though there is plenty of below the line low private   *
  * storage available. If the failing getmain is for low        *
  * private subpools 0-127,129-132,240 or 250-252 and the       *
  * getmain is issued under the RCT (Region Control Task) TCB,  *
  * the getmain request must be satisfied from the System       *
  * Region area from addresses x'1000' to x'5000'.              *
  *                                                             *
  * Once you have determined the address of the TCB under which *
  * the failing getmain was issued (from SYSTRACE, IEA705I      *
  * message, etc.), verify if the getmain is being issued from  *
  * the RCT task.                                               *
  * Issue IPCS option 6 command "SUMMARY FORMAT" and find the   *
  * ASCBRCTP field (ASCB + x'7C'). This contains the RCT TCB    *
  * address, for example:                                       *
  *                                                             *
  * ASCB: 00F7E200                                              *
  * .                                                           *
  * .                                                           *
  * +007C  RCTP..... 008FE1B8                                   *
  *                                                             *
  * The RCT TCB is always the first TCB in the address space.   *
  * The ACTIVE RBS under the RCT TCB will always show           *
  * EP....... IEAVAR00 under the first PRB.                     *
  * Maxing to the bottom of SUMMARY FORMAT will also show the   *
  * RCT TCB as the FIRST TCB. For example:                      *
  *                                                             *
  *    * * * *   T C B   S U M M A R Y   *                      *
  *                                                             *
  * JOB SCE9878B ASID 0099 ASCB 00F7E200 FW                     *
  * 00000005                                                    *
  *     TCB AT    CMP      NTC      OTC                         *
  *    008FE1B8 00000000 00000000 00000000 <----- RCT TCB       *
  *    008FF1D8 00000000 00000000 008FE1B8                      *
  *    008FDE28 00000000 008FF1D8 008FE1B8                      *
  *    008E9300 00000000 00000000 008FDE28                      *
  *    008D57D8 00000000 00000000 008E9300                      *
  *                                                             *
  *                                                             *
  * VSMDATA under Task Related Subpool Information will also    *
  * show the RCT TCB information formatted first. For example:  *
  *                                                             *
  * T A S K - R E L A T E D   S U B P O O L  I N F O R M A T I  *
  *                                                             *
  *  DATA FOR TCB AT ADDRESS 008FE1B8                           *
  *                                                             *
  * VSMDATA under System Region Descriptor will in most cases   *
  * show the following:                                         *
  *                                                             *
  * SYSTEM REGION DESCRIPTOR DATA FOLLOWS                       *
  *                                                             *
  *    --START ADDR 00001000 SIZE     4000                      *
  *                                                             *
  *    --FREE BLOCKS OF STORAGE                                 *
  *                                                             *
  *       No free blocks of storage                             *
  *                                                             *
  ***************************************************************
  

Local fix

• Use the above information in conjunction with II05506.
  -
  It is suggested that code that may be given control
  under the RCT TCB issue its getmains for high private
  subpool 229 (fetch protected) or subpool 230 (not fetch
  protected). Use of a high private subpool will cause
  the getmain to be satisfied above the System Region
  area.
  -
  One example of how code would get control under the
  RCT TCB would be a subsystem function routine for
  WTO broadcast (function code 9).
  -
  Thanks to Steve Emge from Computer Sciences Corporation
  for help in authoring this info apar.
  

Problem summary

Problem conclusion

Temporary fix

Comments

•  This info apar is now closed.
  

APAR Information

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

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

Fix information

Applicable component levels