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 7.2.0 Last updated on 24 Jun 2020 at 09:27:08 EDT.
Copyright IBM Corporation, 1990, 2020