CAABK Back to Index page
 
Prolog 
Control Block Contents 
   CAABK 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.


  CAABK Prolog Top of page
 
 NAME       : HCPCAABK
 DESCRIPTION: CP-use Address space Allocation block
 DSECT      : CAABK
 FUNCTION   : Allocation of virtual addresses in CP-use
              address spaces
 LOCATED BY : ASCTYPTR field of ASCBK
 CREATED BY : Creation of a HCPHAM-managed address space, either
              by HCPASMCR or its callers.
 DELETED BY : Never deleted.
 SERIALIZED :
              All fields except reorganization fields serialized
              by CAALOCK held exclusive.  ASCLOCK in the ASCBK for
              this address space must be held shared when obtain-
              CAALOCK.  If ASCLOCK is held exclusive, CAALOCK need
              not be held.
 RELOCATION CONSIDERATIONS : None
 
 
  CAABK Control Block Content Top of page
 

 CAABK DSECT Top of page
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure CAABK CP-use Address space Allocation block 0000 0 Address 8 CAAAVAIL Anchor of a chain of PGMBK FRMTE(s) containing all deallocated PTEs below the address space's high water mark (CAAHIWTR). The PGMBK FRMTE(s) on this chain are sorted in ascending virtual address order. A CAAAVAIL of zeros indicates an empty chain. This chain is ended by a fullword of zeros in FRMFPNTG. Hold CAALOCK or ASCLOCK exclusive when updating this field. 0008 8 Dbl-Word 8 CAAHIWTR Virtual page address corresponding to the next available PTE in this CP-use address space. All pages below this mark are either currently allocated or are chained on CAAAVAIL. CAAHIWTR never points at an allocated page. No pages above CAAHIWTR are ever allocated or chained on CAAAVAIL. Hold CAALOCK or ASCLOCK exclusive when updating this field. 0008 8 Signed 4 CAAHIWTRH High half of virtual address 000C 12 Signed 4 CAAHIWTRL Low half of virtual address 0010 16 Signed 4 CAAFPTE Count of PTEs in this CP-use address space that exist but do not currently hold an allocated page. This number is an indication of the amount of host real storage currently allocated to map this CP-use address space, but is not being used. This number can therefore be used to determine when it would be beneficial to reorganize the address space. Hold CAALOCK or ASCLOCK exclusive when updating this field. 0014 20 Signed 4 CAAUSTE Count of used segment table entries in this CP-use address space. Hold CAALOCK or or ASCLOCK exclusive when updating this field. 0018 24 Signed 4 CAALOCK CP-use address space allocation lock. This is an informal spin lock. Must be held when updating certain CAABK fields (see above). ASCLOCK must be held shared to obtain this lock. If ASCLOCK is held exclusive, there is no need to obtain this lock. 001C 28 Signed 4 CAAROGCT Number of times this address space has been reorganized. Hold CAAROGLK when updating this field. 0020 32 Dbl-Word 8 CAAREORG Time of day last reorganization occured for this address space. Hold CAAROGLK when updating this field. 0028 40 Bitstring 1 CAAROGLK Address space reorganization test and set (TS) lock. 0029 41 Bitstring 1 * (3) Reserved for future IBM use 002C 44 Signed 4 * (3) Reserved for future IBM use 0038 56 Signed 4 CAAFSI (0) Function-specific information section 00000007 CAASIZE (*-CAABK+7)/8 Size, in doublewords, of CAABK.
 
 
  CAABK Storage Layout Top of page
 
          
*** CAABK - CP-use Address space Allocation block
*
*     +-------------------------------------------------------+
*   0 |                       CAAAVAIL                        |
*     +-------------------------------------------------------+
*   8 |                       CAAHIWTR                        |
*     +-------------------------------------------------------+
*  10
*
*** CAABK - CP-use Address space Allocation block
          
*** Overlay for CAAHIWTR in CAABK
*
*     +---------------------------+---------------------------+
*   8 |        CAAHIWTRH          |        CAAHIWTRL          |
*     +---------------------------+---------------------------+
*  10 |         CAAFPTE           |         CAAUSTE           |
*     +---------------------------+---------------------------+
*  18 |         CAALOCK           |         CAAROGCT          |
*     +---------------------------+---------------------------+
*  20 |                       CAAREORG                        |
*     +------+--------------------+---------------------------+
*  28 |:ROGLK|////////////////////|///////////////////////////|
*     +------+--------------------+///////////////////////////|
*     |///////////////////////////////////////////////////////|
*     +-------------------------------------------------------+
*
*** Overlay for CAAHIWTR in CAABK
 
 
  CAABK Cross Reference Top of page
 
 
Symbol         Dspl Value
-------------- ---- -----
CAAAVAIL       0000
CAAFPTE        0010
CAAFSI         0038
CAAHIWTR       0008
CAAHIWTRH      0008
CAAHIWTRL      000C
CAALOCK        0018
CAAREORG       0020
CAAROGCT       001C
CAAROGLK       0028
CAASIZE        0038 00000007
CAAUSTE        0014
 
This information is based on z/VM 7.3.0 Last updated on 22 Jun 2022 at 15:47:48 EDT.
Copyright IBM Corporation, 1990, 2022