PPDBK | Back to Index page

| Prolog Control Block Contents PPDBK 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.

PPDBK Prolog | Top of page

     NAME       : HCPPPDBK
     DESCRIPTION: Paged PGMBK Data block
     DSECT      : PPDBK
     FUNCTION   : A PPDBK contains information required to find
                  and process an STE corresponding to a paged
                  PGMBK (PTRM page) which has been paged to DASD.
     LOCATED BY : The PPDBK address is saved in the invalid PTRM PTE
                  for PTRM pages (paged PGMBKs) that reside on DASD.
                  The address is saved in a hashed format so that the
                  Invalid and Page Protect bits of the PTRM PTE are
                  left undisturbed; HCPISTEA macro is used to insert
                  the PPDBK address into the PTRM PTE, HCPGSTEA macro
                  is used to extract the PPDBK address from the PTRM
                  PTE.
     CREATED BY : HCPHRPOP when a PTRM page is invalidated,
                  in preparation for the PTRM page (pageable PGMBK)
                  potentially being paged to DASD.
                  HCPPMPRB when a PTRM page (paged PGMBK) is
                  migrated from expanded storage to DASD.
                  HCPHRUSM when processing a segment table
                  relocation, and a PTRM page (pageable PGMBK) on
                  DASD, but without a PPDBK address in the PTRM PTE,
                  is encountered.
     DELETED BY : HCPHTUPF when a PTRM page (paged PGMBK)
                  is read in from DASD.
                  HCPPTAQA when a PTRM page (pageable PGMBK) is paged
                  to expanded storage instead of DASD.
     SERIALIZED :
                  Serialized by PTRM PTE serialization, though to use
                  or change the PPDSTE field, (at least) a share of
                  VMDPTIL on the virtual configuration that owns
                  the corresponding segment table entry is required,
                  to serialize against concurrent destructive changes
                  to the segment table (such as segment table relocate
                  for resize during NSS/DCSS imbed/unimbed).
     COMMENTS   :

PPDBK Control Block Content | Top of page

     PPDBK DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      PPDBK          Paged PGMBK Data block
    0000    0 Address      8 PPDSTE         Address of STE corresponding to
                                            paged PGMBK
    0008    8 Address      4 PPDVMDBK       Address of the owning vconfig's
                                            base VMDBK
              0000000C       PPDBKLEN       *-PPDBK Size of one PPDBK in
                                            bytes
              00000002       PPDBKSIZ       ((*-PPDBK)+7)/8 Size of one PPDBK
                                            in dws
          End of PPDBK definitions

PPDBK Storage Layout | Top of page

    *** PPDBK - Paged PGMBK Data block
    *
    *     +-------------------------------------------------------+
    *   0 |                        PPDSTE                         |
    *     +---------------------------+---------------------------+
    *   8 |         PPDVMDBK          | C
    *     +---------------------------+
    *
    *** PPDBK - Paged PGMBK Data block

PPDBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    PPDBKLEN       0008 0000000C
    PPDBKSIZ       0008 00000002
    PPDSTE         0000
    PPDVMDBK       0008

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:29:42 EDT.
Copyright IBM Corporation, 1990, 2020