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Prolog 
Control Block Contents 
   LCPBK DSECT
Storage Layout 
Cross Reference (Contains links to field and bit definitions)
Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM.


  LCPBK Prolog Top of page
 
 NAME       : HCPLCPBK
 DESCRIPTION: Limiting CPU Pool system block
              =        =   =           =   =
 DSECT      : LCPBK
 FUNCTION   : This control block holds all of the system level fields
              for the CPU Pooling line item.  This includes the pointers
              to the chain of LIMBKs (1 per CPU Pool defined), the LIMBK
              CHAIN LOCK, and any other fields needed at the system level.
              There is ONE HCPLCPBK per z/VM system.
 LOCATED BY : SYSLCPBK: SYSCM pointer to the LCPBK for the system
              LIMNEXT:  LIMBK chain FORWARD pointer to NEXT LIMBK
              LIMPREV:  LIMBK chain BACKWARD pointer to PREVIOUS LIMBK
 CREATED BY : HCPISR    At initialization of the system.
 DELETED BY : NONE
 REFERENCES : HCPLIMBK: Limiting Control Block for a CPU Pool
 SERIALIZED : HCPISRM only runs during system initialization time so no
              serialization is needed.
              The LIMBK CHAIN LOCK (LCPLLCK) is contained in this
              control block and is used to serialize the content of
              specific LIMBK/VMDBK fields as well as the LIMBK CHAIN
              which consists of the LCPNEXT/LCPPREV/LIMNEXT/LIMPREV
              pointers. When CPU Pooling code needs multiple locks,
              the locks needed *MUST* be obtained in this order to
              prevent a deadlock:
              1. SYSRLOLCK  - Shared/Exclusive defer lock to serialize
              access to the RLOBK list. The RLOBK and
              this lock are only used for VMRELOCATION.
              2. LCPLLCK    - Shared/Exclusive defer lock to serialize
              access to the LIMBK CHAIN as well
              as fields in the VMDBK and LIMBK.
              3. SCHEDULER  - Shared/Exclusive defer lock to serialize
              scheduler tasks as well as fields in the
              VMDBK and LIMBK.
              4. LOCAL CYCLIC LIST - SPIN lock to serialize a user's
              chain of VMDBKs.
 RELOCATION CONSIDERATIONS : None
 COMPATIBILITY AND MIGRATION CONCERNS : All system level fields for CPU Pooling should be put
              in this control block and not HCPSYSCM.
 COMMENTS   : Any part including this COPY file needs to also include
              HCPLKWRD (General Lock Word) copy file to compile
              without an error on LKWRDSIZ.
              The 1/19/2011 version of BICOPY VMSKEL was used to create
              this new control block.
 
 
  LCPBK Control Block Content Top of page
 

 LCPBK DSECT Top of page
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure LCPBK Limiting CPU Pool system block 0000 0 Dbl-Word 8 LCPLLCK (3) LKWRD for LIMBK CHAIN LOCK which serializes: - The LIMBK chain (LCPNEXT, LCPPREV, LIMNEXT, LIMPREV) - Fields in the LIMBK - SET SRM LIMITHARD DEADLINE versus DEFINE CPUPOOL command 0018 24 Address 4 LCPNEXT Next (first) LIMBK address The LIMBK CHAIN is double-linked, circular, & includes the anchor (LCPNEXT/LCPPREV). When empty, LCPNEXT=LCPPREV=ADDR(LCPNEXT). With 2 LIMBKS, LCPNEXT/LIMNEXT pointers are followed to get LCPNEXT->LIMBK1.LIMNEXT-> LIMBK2.LIMNEXT->LCPNEXT. Serialized by LIMBK CHAIN LOCK 001C 28 Address 4 LCPPREV Previous (last) LIMBK address The LIMBK CHAIN is double-linked, circular, & includes the anchor (LCPNEXT/LCPPREV). When empty, LCPNEXT=LCPPREV=ADDR(LCPNEXT). With 2 LIMBKS, LCPPREV/LIMPREV pointers are followed to get: LCPPREV->LIMBK2.LIMNEXT LIMBK2.LIMPREV->LIMBK1.LIMNEXT LIMBK1.LIMPREV->LCPNEXT. Serialized by LIMBK CHAIN LOCK 0020 32 Bitstring 1 LCPCPUAF CPU Affinity flag byte ON =CPU Affinity ON OFF=CPU Affinity SUPPRESSED CPU Affinity is a concept that only applies to secondary processors (IFL, zIIP, zAAP, ICF). CPU pools can only limit CPUs of type IFL or CP. Since CP processors are not secondary processors, a userid's CPU AFFINITY setting does not effect what real processors the work assigned to virtual CP processors runs on. Thus, only CPU AFFINITY for IFL engines matters to the CPU pooling support and is remembered here. See HCPCPA's prologue General Comments for more details on CPU Affinity. Serialized by SCHEDULER LOCK 1... .... LCPIFL X'80' IFL engine CPU Affinity 0021 33 Bitstring 1 * (3) Reserved for IBM use 0024 36 Signed 4 LCPCIFLA Sequence number of current IFL engine CPU Affinity toggle. Serialized by SCHEDULER LOCK 0028 40 Dbl-Word 8 * Reserved for IBM use 0030 48 Dbl-Word 8 * Reserved for IBM use 0038 56 Dbl-Word 8 * Reserved for IBM use 0040 64 Dbl-Word 8 * Reserved for IBM use 00000009 LCPSIZE (*-LCPBK+7)/8 size in double words 00000048 LCPBSIZE LCPSIZE*8 size in bytes
 
 
  LCPBK Storage Layout Top of page
 
          
*** LCPBK - Limiting CPU Pool system block
*
*     +-------------------------------------------------------+
*   0 |                                                       |
*     =                       LCPLLCK                         =
*     |                                                       |
*     +---------------------------+---------------------------+
*  18 |         LCPNEXT           |         LCPPREV           |
*     +------+--------------------+---------------------------+
*  20 |:CPUAF|////////////////////|         LCPCIFLA          |
*     +------+--------------------+---------------------------+
*  28 |///////////////////////////////////////////////////////|
*     +-------------------------------------------------------+
*  30 |///////////////////////////////////////////////////////|
*     +-------------------------------------------------------+
*  38 |///////////////////////////////////////////////////////|
*     +-------------------------------------------------------+
*  40 |///////////////////////////////////////////////////////|
*     +-------------------------------------------------------+
*  48
*
*** LCPBK - Limiting CPU Pool system block
 
 
  LCPBK Cross Reference Top of page
 
 
Symbol         Dspl Value
-------------- ---- -----
LCPBSIZE       0040 00000048
LCPCIFLA       0024
LCPCPUAF       0020
LCPIFL         0020 80
LCPLLCK        0000
LCPNEXT        0018
LCPPREV        001C
LCPSIZE        0040 00000009
 
This information is based on z/VM 7.3.0 Last updated on 22 Jun 2022 at 15:52:00 EDT.
Copyright IBM Corporation, 1990, 2022