PODBK | Back to Index page

| Prolog Control Block Contents PODBK 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.

PODBK Prolog | Top of page

     NAME       : HCPPODBK
     DESCRIPTION: Relocation Pages on DASD Block
     DSECT      : PODBK
     FUNCTION   : A Relocation Pages on DASD block will hold information
                  about the pages from DASD that will be sent from the
                  source to the destination during relocation.
     LOCATED BY : PODBKs are queued in a gated queue that is anchored
                  at RLOBK.RLOPODGQ. Each relocation will have a separate
                  gated queue.  The first two fullwords of the gated
                  queue field point to the first and last WORKITEM
                  (HCPPODBK).
     CREATED BY : A Relocation Pages on DASD block is allocated by
                  HCPPODNQ and HCPPODPW in HCPPOD.
     DELETED BY : A Relocation Pages on DASD block is released by
                  HCPPODDQ and/or HCPPODSQ in HCPPOD.
     REFERENCES : See HCPPOD for information about the usage of this
                  block.
                  See HCPPOD for information about the role that this
                  block plays in PGMBK Walker (HCPRLTPW) throttling.
     SERIALIZED : The queueing and dequeing of PODBKs are serialized by
                  the gated queue macro (HCPGQMGR).
     RELOCATION CONSIDERATIONS : - This block is not relocated during a relocation of a
                  guest from one system to another.
                  - During a relocation, one PODBK is created for each
                  guest page that is on DASD and needs to be sent to
                  the destination system.
     NOTES      : There are two flavors of HCPPODBKs.
                  1.- Contains a PTE from a page on DASD that
                  relocation needs to send.
                  2.- Contains a Post-And-Wait message to notify
                  HCPPODDQ that the complete address space was
                  processed for the current relocation memory
                  pass.
                  DSECT USED AS WORKING ELEMENT FOR THE GATED QUEUE MANAGER
                  (If FLAG not set, then PODBK is defined as follows)
                  +------+------+------+------+------+------+------+------+
                  | NEXT ELEMT IN GATED QUEUE | FLAG |  RESERVED FOR IBM  |
                  +------+------+------+------+------+------+------+------+
                  |                  PTE FOR PAGE ON DASD                 |
                  +------+------+------+------+------+------+------+------+
                  |    ADDRESS OF THE RLOBK   |      RESERVED FOR IBM     |
                  +------+------+------+------+------+------+------+------+
                  (If FLAG is set to PODNOTIFY, then PODBK is defined as
                  follows)
                  +------+------+------+------+------+------+------+------+
                  | NEXT ELEM IN GATED QUEUE  | FLAG |  RESERVED FOR IBM  |
                  +------+------+------+------+------+------+------+------+
                  |   RESERVED FOR IBM USE    | CPEBK TASK FOR POST & WAIT|
                  +------+------+------+------+------+------+------+------+
                  |    ADDRESS OF THE RLOBK   |      RESERVED FOR IBM     |
                  +------+------+------+------+------+------+------+------+

PODBK Control Block Content | Top of page

     PODBK DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      PODBK          Relocation Pages on DASD Block
    0000    0 Address      4 PODNEXT        Reserved for Gated Queue Manager
                                            for use as a queue chain pointer
    0004    4 Bitstring    1 PODFLAG        Work element flag
              00000080       PODNOTIFY      X'80' PODNOTIFY This work element
                                            is for notification processing.
                                            >>>> BEGIN DEBUG ONLY
                                            CODE <<<< This debug
                                            only code is taking part of the
                                            reserved space. >>>>
                                            END DEBUG ONLY CODE
                                            <<<<
    0005    5 Bitstring    1 * (3)          Reserved for future IBM use.
    0008    8 Address      8 PODPTE         PTE for page on DASD.
    0010   16 Address      4 PODRLO         Address of the RLOBK related to
                                            this PTE
    0014   20 Address      4 PODPWI         Address of PWIBK
              00000003       PODDSIZE       ((*-PODBK)+7)/8 PODBK size in
                                            double-words
              00000018       PODBSIZE       PODDSIZE*8 size in bytes
    0008    8 Address      4 *              Reserved for future IBM use.
    000C   12 Address      4 PODPOST        CPEBK address to stack when this
                                            work element is processed.

PODBK Storage Layout | Top of page

    *** PODBK - Relocation Pages on DASD Block
    *
    *     +---------------------------+------+--------------------+
    *   0 |         PODNEXT           |:FLAG |////////////////////|
    *     +---------------------------+------+--------------------+
    *   8 |                        PODPTE                         |
    *     +---------------------------+---------------------------+
    *  10 |          PODRLO           |          PODPWI           |
    *     +---------------------------+---------------------------+
    *  18
    *
    *** PODBK - Relocation Pages on DASD Block

    *** Overlay for PODPTE in PODBK
    *
    *     +---------------------------+---------------------------+
    *   8 |///////////////////////////|         PODPOST           |
    *     +---------------------------+---------------------------+
    *  10
    *
    *** Overlay for PODPTE in PODBK

PODBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    PODBSIZE       0014 00000018
    PODDSIZE       0014 00000003
    PODFLAG        0004
    PODNEXT        0000
    PODNOTIFY      0004 00000080
    PODPOST        000C
    PODPTE         0008
    PODPWI         0014
    PODRLO         0010

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:29:41 EDT.
Copyright IBM Corporation, 1990, 2020