SSHBK | Back to Index page

| Prolog Control Block Contents SSHBK DSECT SSHVBK 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.

SSHBK Prolog | Top of page

     NAME       : HCPSSHBK
     DESCRIPTION: User Share Settings control block
     DSECT      : SSHBK
     FUNCTION   : HCPSSHBK contains an array of share values for a
                  user per processor type as set by the SET SHARE
                  command.  It is used by the System Resource
                  Manager (Scheduler) to schedule system resources
                  for the user.
     LOCATED BY : VMDSSHBK pointer
     CREATED BY : HCPBVM during user logon
     DELETED BY : HCPUSP during logoff processing
     REFERENCES : None
     SERIALIZED : Scheduler lock (SRMSLOCK)
     RELOCATION CONSIDERATIONS : This control block is relocated as part of a live
                  guest relocation (LGR).  The bits and fields that
                  need to be relocated are defined in the
                  corresponding LGRSSHBK COPY file.  Whenever changes
                  are made to this control block, consideration must
                  be given to any effects these changes will have on
                  a relocation.  If any new fields or bits are
                  defined, they may need to be relocated.  If
                  existing bits or fields are changed, corresponding
                  modifications may be required in the LGR version of
                  this control block.  Consider also the effects of
                  these changes on a relocation involving a back-level
                  release of CP.
     COMPATIBILITY AND MIGRATION CONCERNS : Prior to the support
                  for the TYPE operand on the SET SHARE command, the
                  fields in this control block were not saved but were
                  calculated by adding the corresponding fields in each
                  VMDBK in the virtual configuration.  This calculation
                  was adequate because the share values were set per user,
                  and applied to all CPU types.  Now, share values are set
                  per CPU type and may even be set for a type of CPU that
                  the user has not yet defined.  This requires a more
                  permanent place to store these values for each CPU type
                  for each user.

SSHBK Control Block Content | Top of page

     SSHBK DSECT
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    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      SSHBK          User Share Settings control block
    0000    0 Bitstring   16 SSHARRAY (0)
              0000000E       SSHSIZE        (*-SSHBK+7)/8 SSHBK size in
                                            double words
              00000070       SSHBSIZE       SSHSIZE*8 SSHBK size in bytes

     SSHVBK DSECT
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    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      SSHVBK         User Share Settings control block
    0000    0 Signed       4 SSHSHARS (0)   A symbol used as a base for
                                            indexing the following two
                                            fields, SSHRELSH and SSHABSSH.
                                            Code depends on these fields each
                                            being fullwords and consecutive
                                            IN THE FOLLOWING ORDER.
    0000    0 Signed       4 SSHRELSH       The relative share setting for
                                            this CPU type. Code should be
                                            able to handle a range of
                                            1-32767, although currently, only
                                            1-10000 is valid.
    0004    4 Signed       4 SSHABSSH       The absolute share setting for
                                            this CPU type. The range is
                                            0.01-1.00.
    0008    8 Signed       4 SSHMXSHR       The max-share setting for this
                                            CPU type. IT is either ABSOLUTE
                                            or RELATIVE the SSHMXSHA flag
                                            tells which. If it is RELATIVE it
                                            is an integer. If ABSOLUTE, it is
                                            stored as a fraction of the
                                            system, scaled SHRSCALE. If the
                                            user has no LIMIT it is zero.
                                            (See SSHLIMTH.)
                 The following flag byte is defined to have the same
                 values as the DVMDLIMT flag.
    000C   12 Bitstring    1 SSHFLG1        Share flags byte 1
              .1.. ....      SSHLIMH        X'40' SSHLIMH Limithard share
                                            option
              ..1. ....      SSHNMSHA       X'20' SSHNMSHA Normal share
                                            setting (SSHSHARS) for this CPU
                                            type for this user is ABSOLUTE,
                                            not RELATIVE.
              ...1 ....      SSHMXSHA       X'10' SSHMXSHA Max-share setting
                                            (SSHMXSHR) for this CPU type for
                                            this user is ABSOLUTE, not
                                            RELATIVE.
    000D   13 Bitstring    1 SSHFLG2        Share flags byte 2
              1... ....      SSHVINV        X'80' SSHVINV SSHVBK is marked
                                            invalid
    000E   14 Bitstring    2 *              Reserved for IBM use
              00000010       SSHVSIZE       (*-SSHVBK) SSVBK size in bytes

SSHBK Storage Layout | Top of page

    *** SSHBK - User Share Settings control block
    *
    *
    *** SSHBK - User Share Settings control block

    *** SSHVBK - User Share Settings control block
    *
    *     +---------------------------+---------------------------+
    *   0 |         SSHRELSH          |         SSHABSSH          |
    *     +---------------------------+------+------+-------------+
    *   8 |         SSHMXSHR          |:FLG1 |:FLG2 |/////////////|
    *     +---------------------------+------+------+-------------+
    *  10
    *
    *** SSHVBK - User Share Settings control block

SSHBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    SSHABSSH       0004
    SSHARRAY       0000
    SSHBSIZE       0000 00000070
    SSHFLG1        000C
    SSHFLG2        000D
    SSHLIMH        000C 40
    SSHMXSHA       000C 10
    SSHMXSHR       0008
    SSHNMSHA       000C 20
    SSHRELSH       0000
    SSHSHARS       0000
    SSHSIZE        0000 0000000E
    SSHVINV        000D 80
    SSHVSIZE       000E 00000010

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:30:51 EDT.
Copyright IBM Corporation, 1990, 2020