Programming Interface Information: This information is NOT intended to be
used as Programming Interfaces of z/VM.

XSTMG

Prolog  

Control Block Contents  
   XSTMG DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  


XSTMG Prolog

 Name       : HCPXSTMG
 Description: Expanded storage management data
 DSECT      : XSTMG
 Function   : This block is used to keep track of global
              Information associated with the expanded
              Storage facility and block paging.
 Located by : This DSECT overlays the data Entry Point
              HCPPGDXT.
 Created by : HCPPGD is loaded by the system during IPL.
              The XSTMG is initialized by HCPESCDI.
 Deleted by : never deleted.

 

XSTMG Control Block Content


XSTMG DSECT

Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      XSTMG          Expanded storage management data
0000    0 Signed       4 XSTMGSTR (0)   Start of XSTMG block
0000    0 Signed       4 XSTFLAGS (0)   Flags for the XSTMG block.
                                        Updated with compare and swap.
0000    0 Address      1 XSTSTAFG       Status information flag
          .... ...1      XSTNCONF       X'01' Xstore is not configured to
                                        the system.
          .... ...1      XSTOFFLN       X'01' Xstore was taken offline
                                        because all blocks are in error.
          .... ..1.      XSTMPDSB       X'02' Xstore has been disabled
                                        for CP paging temporarily until
                                        at least one increment can be
                                        brought online during
                                        initilization or recovery from a
                                        machine check. This bit has no
                                        meaning if XSTOFFLN is on.
          .... .1..      XSTNAVAL       X'04' Indicates that there is no
                                        XSTORE available for allocation.
                                        This may happen if all XSTORE has
                                        been attached to a guest or the
                                        CP partition has been completely
                                        allocated.
          .... 1...      XSTMDALL       X'08' Indicates that there is no
                                        XSTORE available for paging
                                        allocation. The Xstore is to be
                                        used only for allocation to
                                        Minidisk Cache.
          ...1 ....      XSTEXTMP       X'10' If on, indicates that Read
                                        Expanded Storage Usability Bit
                                        Map Extended is installed. If
                                        off, nothing is implied about the
                                        existence of other usability map
                                        facilities.
          .1.. ....      XSTRREQD       X'40' Usability-map repair is
                                        required. When this bit is on,
                                        work has been stacked to perform
                                        the repair action. This bit has
                                        no meaning if XSTOFFLN is on.
     The following are the flags that indicate status.
0001    1 Bitstring    1 XSTFUTCT       COUNT OF STAMPS WITH FUTURE TIMES
0002    2 Signed       2 XSTAVGAG       Average age of paging XBLKs
0004    4 Signed       4 XSTSTATL       XSTORE statistics lock used to
                                        serialize updates to : XSTCTXTS,
                                        XSTEPOCH, PGMXSTCT, ASCCTXBK,
                                        ASCCTXRD, and ASCCTXWT.
0008    8 Signed       4 XSTCTXTS       Count of XSTORE blocks currently
                                        in use for CP Paging. Used by MIG
                                        to calculate average timestamp.
                                        Serialized by XSTSTATL.
000C   12 Signed       4 XSTCTXER       Number of blocks in error that
                                        have not yet been reflected to a
                                        guest. Update holding XSTBUFLK.
0010   16 Signed       4 XSTOTALB       Amount of XSTORE online in
                                        blocks. It represents the number
                                        of blocks in "configured"
                                        increments. Set at initialization
                                        and not changed.
0014   20 Signed       4 XSTGUEST       Number of blocks attached to
                                        virtual machines including error
                                        blocks. To update hold HCPPGDXL.
0018   24 Signed       4 XSTINCRB       Number of blocks per XDRBK.
001C   28 Signed       4 XSTCPINC       Amount of xstore in blocks that
                                        are in the "CP" state and are
                                        "Configured". It includes error
                                        blocks but excludes CP-Retained
                                        blocks. To update hold HCPPGDXL.
0020   32 Signed       4 XSTCPSTR       Total number of blocks that are
                                        in the cp-retained state
                                        including blocks in error. To
                                        update hold HCPPGDXL.
0024   36 Signed       4 XSTPEDRT       Amount of xstore in blocks that
                                        is waiting to be assigned the
                                        retained state. This is pending
                                        retain. The sum of XSTCPSTR and
                                        XSTPEDRT is the amount specified
                                        on the last RETAIM XSTORE
                                        command. To update hold HCPPGDXL.
0028   40 Signed       4 XSTMSKIP       XBLKs skipped by migrator because
                                        they were too young
002C   44 Signed       4 XSTALLMB       Sum of BLKDM+BLKCY+BLKSH+BLKSY
                                        Used in timestamp adjustment
     The following area is used by XSTORE migration
0030   48 Signed       4 * (0)          Migration lock and flag word
0030   48 Bitstring    1 XSTMIGLK       TS LOCK BYTE FOR MIGRATION
0031   49 Bitstring    1 XSTMIFLG       MIGRATION FLAG BYTE
          1... ....      XSTMISLP       X'80' Migration is awaiting
                                        redrive
          .1.. ....      XSTNORML       X'40' Normal migration in
                                        progress
          ..1. ....      XSTFLUSH       X'20' Flush is in progress
          ...1 ....      XSTPTIL        X'10' The PTIL lock and the owned
                                        ASCBK queue lock (VMDASCLK) are
                                        held for the current VMDBK
          .... 1...      XSTDCSS        X'08' DCSS scan is in progress
          .... .1..      XSTNSS         X'04' NSS scan is in progress
          .... 11..      XSTSHARE       XSTNSS+XSTDCSS NSS or DCSS scan
                                        is in progress
          .... ..1.      XSTRESUM       X'02' Migration is restarting
                                        after loss of control
          .... ...1      XSTSHAS        X'01' Shared address space scan
                                        is in progress
          .... 11.1      XSTNOCYC       XSTNSS+XSTDCSS+XSTSHAS A
                                        non-cyclic list (NSS, DCSS, or
                                        SHAS) scan is in progress.
     The following represent bit settings for XSTMIFLG
0032   50 Signed       2 XSTBMULT       Used to control number of migrate
                                        buffers obtained at migration
                                        invocation. (XSTBMULT*paging
                                        vols)
          0000000F       XSTMMAX        15 Highest allowed value for
                                        XSBMULT
          00000005       XSTMMIN        5 Lowest value allowed for
                                        XSTBMULT
0034   52 Address      4 XSTCYCLE       The VMDBK address of a user in
                                        the Cyclic List that will be the
                                        next target of migration.
0038   56 Bitstring    4 XSTFRMAQ       MIGRATION FRAME QUEUE (BUFFERS)
003C   60 Signed       4 XSTNUMAQ       Number on the migrate frame queue
          ...1 ....      XSTMIBLF       16 Migrate blocking factor - the
                                        minimum desirable XSTNUMAQ value
                                        to give decent DASD blocking
0040   64 Signed       2 XSTTGTEP       Epoch of target time
0042   66 Signed       2 XSTTARGT       Target age in seconds
0044   68 Signed       2 XSTEPOCH       Current Steal TOD clock epoch
                                        Serialized by XSTSTATL.
0046   70 Signed       2 XSTSTIME       Migrate/steal timer
0048   72 Signed       4 XSTADJTG       When XSTMSKIP hits this value its
                                        time to adjust the target age
004C   76 Signed       4 XSTMAXCT       Num of times target time lowered
0050   80 Bitstring    1 XSTMIFRM       FRAME CODE TO USE ON MIGRATOR
                                        BUFFER FRAMES.
0051   81 Bitstring    1 XSTMIFL2       SECOND MIGRATION FLAG BYTE
     The following represent bit settings for XSTMIFL2
          1... ....      XSTMINTG       X'80' Emergency scan with lowest
                                        tgt
          .1.. ....      XSTCYEND       X'40' Branched to FLSHDONE from
                                        CYCLEND
          ..1. ....      XSTCKGAL       X'20' Branched to FLSHDONE from
                                        CHKCTGAL
          ...1 ....      XSTFNDDS       X'10' Indicate that we noticed a
                                        user whose address space(s) were
                                        being destroyed while we were
                                        attempting to flush XSTORE.
          .... 1...      XSTUSE8K       X'08' Using (or waiting for) an
                                        8K buffer. This bit is only set
                                        when an 8K buffer is required. If
                                        it is ON when buffers are being
                                        returned after I/O, it means
                                        migration should only restart
                                        when 8K buffers are available.
          .... .1..      XSTNDONE       X'04' Normal migration has
                                        completed early without reaching
                                        the high threshold due to the
                                        average age of blocks in expanded
                                        storage becoming too low. If
                                        flush is active, migration will
                                        continue.
0052   82 Signed       2 XSTMINAG       Minimum age to allow migration
0054   84 Signed       4 XSTITIME       TOD of first steal or tmr wrap
0058   88 Signed       8 XSTSUMAG       Sum of ages of migrated blocks
0060   96 Signed       4 XSTUSRDM       Number of dormant guest owned
                                        address spaces that were the
                                        target of migration
0064  100 Signed       4 XSTUSRCY       Number of non-dormant guest owned
                                        address spaces that were the
                                        target of migration
0068  104 Signed       4 XSTUSRSH       Number of Named Saved Systems and
                                        Saved Segments (DCSSs and Segment
                                        Spaces) that were the target of
                                        migration
006C  108 Signed       4 XSTCTGAL       Count of blocks to flush from the
                                        users partition being assigned to
                                        the virtual machine given by
                                        XSTATVMD. To update hold
                                        XSTBUFLK.
0070  112 Signed       4 XSTBLKDM       Number of blocks migrated from a
                                        dormant guest
0074  116 Signed       4 XSTBLKCY       Number of blocks migrated from a
                                        non-dormant guest
0078  120 Signed       4 XSTBLKSH       Number of blocks migrated from a
                                        shared system
007C  124 Signed       4 XSTBLKSY       Number of blocks migrated from
                                        the CP system
0080  128 Signed       4 XSTQUEND       Anchor of current SNT queue
0084  132 Signed       4 XSTMISAQ       Number of frames missing (taken)
                                        from migration frame queue
                                        without being replenished
0088  136 Signed       4 XSTMIFRS       Total number of migration buffer
                                        frames, including both available
                                        (on XSTFRMAQ) and in use frames.
008C  140 Signed       4 XSTMIGS        Count of migrate invocations
0090  144 Signed       4 XSTCTPGM       Count of PGMBKS selected
0094  148 Bitstring    4 XSTFROUT       QUEUE OF FRAMES TO BE WRITTEN
0098  152 Signed       4 XSTLOTHR       Low threshold for migration
009C  156 Signed       4 XSTHITHR       High threshold for migration
00A0  160 Signed       4 XSTRSTLO       XSTLOTHR is raised if XSTLOH20 is
                                        smaller than RSTLO at end of mig
00A4  164 Signed       4 XSTRLOCT       Number of times buffer increased
00A8  168 Signed       4 XSTRSTHI       XSTLOTHR is lowered if XSTLOH20
                                        is larger 3 times in a row at mig
                                        end
00AC  172 Signed       4 XSTRHICT       Number of times buffer decreased
00B0  176 Signed       4 XSTHICNT       Number of times XSTLOH20 was
                                        larger than XSTRSTHI
00B4  180 Signed       4 XSTLOH2O       Minimum number of XSTORE blocks
                                        available during this migration
00B8  184 Signed       4 XSTSKIPA       The number of XBLKs we are
                                        willing to skip before resetting
                                        target
00BC  188 Address      4 XSTCURAS       Current (or last) ASCBK being
                                        migrated from
00C0  192 Address      4 XSTCURVM       Current (or last) VMDBK being
                                        migrated from; contains current
                                        SNTBK address if XSTNSS or
                                        XSTDCSS flag set in XSTMIFLG
00C4  196 Signed       4 XSTSEGCT       Count of STLBK SEGTEs processed
00C8  200 Signed       4 XSTDDSAV       Save area for XSFDD's R13 while
                                        migrator runs.
00CC  204 Signed       4 XSTMDCSA       Save area for MDC flush
00D0  208 Address      4 XSTCURSG       Segment currently being migrated
00D4  212 Address      4 XSTLSTSG       Migratee's final segment
00D8  216 Address      4 XSTDFRAS       ASCBK of deferred address space
00DC  220 Bitstring    4 *              reserved
00E0  224 Signed       4 XSTNOIO        No IO was required for migration
00E4  228 Signed       4 XSTCYCLS       Number of times through cyclic
00E8  232 Signed       4 XSTFLCYC       Number of cycles while flushing
00EC  236 Signed       4 XSTMRABI       Count of pages that were read in
                                        as part of a block but not used
                                        (as seen by migrate)
00F0  240 Signed       4 XSTSRABI       Count of pages that were read in
                                        as part of a block but not used
                                        (as seen by steal)
00F4  244 Signed       4 XSTSRGCT       Single reads for guests
00F8  248 Signed       4 XSTSRSCT       Single reads for system
00FC  252 Signed       4 XSTBPRCT       Blocks of pages read
0100  256 Address      4 XSTATVMD       Address of the VMDBK having
                                        XSTORE attached. This is the base
                                        VMDBK for the primary
                                        configuration for this virtual
                                        machine (VMDORIG). to update hold
                                        XSTBUFLK and hcppgdxl.
0104  260 Signed       4 XSTATLOW       Lowest block number associated
                                        with the partition being attached
                                        to the virtual machine given in
                                        xstatvmd. To update hold xstbuflk
                                        and HCPPGDXL.
0108  264 Signed       4 XSTATHI        Highest block number associated
                                        with the partition being attached
                                        to the virtual machine given in
                                        XSTATVMD. To update hold XSTBUFLK
                                        and HCPPGDXL.
010C  268 Signed       4 XSTATSIZ       Amount of configured expanded
                                        storage being attached to the
                                        virtual machine given in
                                        XSTATVMD. To update hold XSTBUFLK
                                        and HCPPGDXL.
     The following area is used for XSTORE block allocation
0110  272 Signed       4 XSTXBZIP       Times no XSTORE was available
0114  276 Signed       4 XSTXBGET       Number of XSTORE allocations
0118  280 Signed       4 XSTXBREL       Number of XSTORE releases
011C  284 Signed       4 XSTMAXK        Highest XSTORE increment number
0120  288 Signed       4 XSTINCRM       Highest supported hardware
                                        increment number after capping
0124  292 Signed       4 *              Reserved for IBM use
0128  296 Signed       4 XSTCPPAR       Number of blocks in CP partition
                                        available for allocation. This is
                                        the total number of blocks in the
                                        CP and CP-Retained states
                                        excluding those in error. To
                                        update hold HCPPGDXL.
012C  300 Signed       4 XSTCTXAV       Count of available blocks in the
                                        CP partition. To update hold
                                        XSTBUFLK.
          00000130       XSTMGMSZ       *-XSTMGSTR Size of monitored
                                        portion of XSTMG
0130  304 Signed       4 XSTDIRAN       Anchor to the XSTORE directory
0134  308 Signed       4 XSTALCR        Allocation cursor: points to the
                                        directory entry (XDRBK) where the
                                        the last block was allocated.
0138  312 Bitstring    1 XSTBUFLK       TS LOCK FOR BAT BUFFER
0139  313 Bitstring    1 *              RESERVED FOR IBM USE
013A  314 Signed       2 XSTBUFH4       Table entry index size
013C  316 Address      4 XSTBUFHI       End of the BAT buffer
0140  320 Address      4 XSTBUFIX       Next entry to take in BAT buffer
0144  324 Address      4 XSTBUFLO       Addr of start of buffer
0148  328 Signed       4 XSTBUFER (500) The BAT buffer
          00000918       XSTBUFND       * Addr of last entry in the BAT
                                        buffer

 

XSTMG Storage Layout

          
*** XSTMG - Expanded storage management data
*
*     +------+------+-------------+---------------------------+
*   0 |:STAFG|:FUTCT|  XSTAVGAG   |         XSTSTATL          |
*     +------+------+-------------+---------------------------+
*   8 |         XSTCTXTS          |         XSTCTXER          |
*     +---------------------------+---------------------------+
*  10 |         XSTOTALB          |         XSTGUEST          |
*     +---------------------------+---------------------------+
*  18 |         XSTINCRB          |         XSTCPINC          |
*     +---------------------------+---------------------------+
*  20 |         XSTCPSTR          |         XSTPEDRT          |
*     +---------------------------+---------------------------+
*  28 |         XSTMSKIP          |         XSTALLMB          |
*     +------+------+-------------+---------------------------+
*  30 |:MIGLK|:MIFLG|  XSTBMULT   |         XSTCYCLE          |
*     +------+------+-------------+---------------------------+
*  38 |         XSTFRMAQ          |         XSTNUMAQ          |
*     +-------------+-------------+-------------+-------------+
*  40 |  XSTTGTEP   |  XSTTARGT   |  XSTEPOCH   |  XSTSTIME   |
*     +-------------+-------------+-------------+-------------+
*  48 |         XSTADJTG          |         XSTMAXCT          |
*     +------+------+-------------+---------------------------+
*  50 |:MIFRM|:MIFL2|  XSTMINAG   |         XSTITIME          |
*     +------+------+-------------+---------------------------+
*  58 |                       XSTSUMAG                        |
*     +---------------------------+---------------------------+
*  60 |         XSTUSRDM          |         XSTUSRCY          |
*     +---------------------------+---------------------------+
*  68 |         XSTUSRSH          |         XSTCTGAL          |
*     +---------------------------+---------------------------+
*  70 |         XSTBLKDM          |         XSTBLKCY          |
*     +---------------------------+---------------------------+
*  78 |         XSTBLKSH          |         XSTBLKSY          |
*     +---------------------------+---------------------------+
*  80 |         XSTQUEND          |         XSTMISAQ          |
*     +---------------------------+---------------------------+
*  88 |         XSTMIFRS          |         XSTMIGS           |
*     +---------------------------+---------------------------+
*  90 |         XSTCTPGM          |         XSTFROUT          |
*     +---------------------------+---------------------------+
*  98 |         XSTLOTHR          |         XSTHITHR          |
*     +---------------------------+---------------------------+
*  A0 |         XSTRSTLO          |         XSTRLOCT          |
*     +---------------------------+---------------------------+
*  A8 |         XSTRSTHI          |         XSTRHICT          |
*     +---------------------------+---------------------------+
*  B0 |         XSTHICNT          |         XSTLOH2O          |
*     +---------------------------+---------------------------+
*  B8 |         XSTSKIPA          |         XSTCURAS          |
*     +---------------------------+---------------------------+
*  C0 |         XSTCURVM          |         XSTSEGCT          |
*     +---------------------------+---------------------------+
*  C8 |         XSTDDSAV          |         XSTMDCSA          |
*     +---------------------------+---------------------------+
*  D0 |         XSTCURSG          |         XSTLSTSG          |
*     +---------------------------+---------------------------+
*  D8 |         XSTDFRAS          |///////////////////////////|
*     +---------------------------+---------------------------+
*  E0 |         XSTNOIO           |         XSTCYCLS          |
*     +---------------------------+---------------------------+
*  E8 |         XSTFLCYC          |         XSTMRABI          |
*     +---------------------------+---------------------------+
*  F0 |         XSTSRABI          |         XSTSRGCT          |
*     +---------------------------+---------------------------+
*  F8 |         XSTSRSCT          |         XSTBPRCT          |
*     +---------------------------+---------------------------+
* 100 |         XSTATVMD          |         XSTATLOW          |
*     +---------------------------+---------------------------+
* 108 |         XSTATHI           |         XSTATSIZ          |
*     +---------------------------+---------------------------+
* 110 |         XSTXBZIP          |         XSTXBGET          |
*     +---------------------------+---------------------------+
* 118 |         XSTXBREL          |         XSTMAXK           |
*     +---------------------------+---------------------------+
* 120 |         XSTINCRM          |///////////////////////////|
*     +---------------------------+---------------------------+
* 128 |         XSTCPPAR          |         XSTCTXAV          |
*     +---------------------------+---------------------------+
* 130 |         XSTDIRAN          |         XSTALCR           |
*     +------+------+-------------+---------------------------+
* 138 |:BUFLK|//////|  XSTBUFH4   |         XSTBUFHI          |
*     +------+------+-------------+---------------------------+
* 140 |         XSTBUFIX          |         XSTBUFLO          |
*     +---------------------------+---------------------------+
* 148 |                                                       |
*     =                       XSTBUFER                        =
*     |                                                       |
*     +-------------------------------------------------------+
* 918
*
*** XSTMG - Expanded storage management data

 

XSTMG Cross Reference

Symbol         Dspl Value
-------------- ---- -----
XSTADJTG       0048
XSTALCR        0134
XSTALLMB       002C
XSTATHI        0108
XSTATLOW       0104
XSTATSIZ       010C
XSTATVMD       0100
XSTAVGAG       0002
XSTBLKCY       0074
XSTBLKDM       0070
XSTBLKSH       0078
XSTBLKSY       007C
XSTBMULT       0032
XSTBPRCT       00FC
XSTBUFER       0148
XSTBUFHI       013C
XSTBUFH4       013A
XSTBUFIX       0140
XSTBUFLK       0138
XSTBUFLO       0144
XSTBUFND       0148 00000918
XSTCKGAL       0051 20
XSTCPINC       001C
XSTCPPAR       0128
XSTCPSTR       0020
XSTCTGAL       006C
XSTCTPGM       0090
XSTCTXAV       012C
XSTCTXER       000C
XSTCTXTS       0008
XSTCURAS       00BC
XSTCURSG       00D0
XSTCURVM       00C0
XSTCYCLE       0034
XSTCYCLS       00E4
XSTCYEND       0051 40
XSTDCSS        0031 08
XSTDDSAV       00C8
XSTDFRAS       00D8
XSTDIRAN       0130
XSTEPOCH       0044
XSTEXTMP       0000 10
XSTFLAGS       0000
XSTFLCYC       00E8
XSTFLUSH       0031 20
XSTFNDDS       0051 10
XSTFRMAQ       0038
XSTFROUT       0094
XSTFUTCT       0001
XSTGUEST       0014
XSTHICNT       00B0
XSTHITHR       009C
XSTINCRB       0018
XSTINCRM       0120
XSTITIME       0054
XSTLOH2O       00B4
XSTLOTHR       0098
XSTLSTSG       00D4
XSTMAXCT       004C
XSTMAXK        011C
XSTMDALL       0000 08
XSTMDCSA       00CC
XSTMGMSZ       012C 00000130
XSTMGSTR       0000
XSTMIBLF       003C 10
XSTMIFLG       0031
XSTMIFL2       0051
XSTMIFRM       0050
XSTMIFRS       0088
XSTMIGLK       0030
XSTMIGS        008C
XSTMINAG       0052
XSTMINTG       0051 80
XSTMISAQ       0084
XSTMISLP       0031 80
XSTMMAX        0032 0000000F
XSTMMIN        0032 00000005
XSTMPDSB       0000 02
XSTMRABI       00EC
XSTMSKIP       0028
XSTNAVAL       0000 04
XSTNCONF       0000 01
XSTNDONE       0051 04
XSTNOCYC       0031 0D
XSTNOIO        00E0
XSTNORML       0031 40
XSTNSS         0031 04
XSTNUMAQ       003C
XSTOFFLN       0000 01
XSTOTALB       0010
XSTPEDRT       0024
XSTPTIL        0031 10
XSTQUEND       0080
XSTRESUM       0031 02
XSTRHICT       00AC
XSTRLOCT       00A4
XSTRREQD       0000 40
XSTRSTHI       00A8
XSTRSTLO       00A0
XSTSEGCT       00C4
XSTSHARE       0031 0C
XSTSHAS        0031 01
XSTSKIPA       00B8
XSTSRABI       00F0
XSTSRGCT       00F4
XSTSRSCT       00F8
XSTSTAFG       0000
XSTSTATL       0004
XSTSTIME       0046
XSTSUMAG       0058
XSTTARGT       0042
XSTTGTEP       0040
XSTUSE8K       0051 08
XSTUSRCY       0064
XSTUSRDM       0060
XSTUSRSH       0068
XSTXBGET       0114
XSTXBREL       0118
XSTXBZIP       0110

This information is based on z/VM V4R1.0.
Last updated on 5 Jun 2001 at 17:21:37 EDT.
Copyright IBM Corporation, 1990, 2001