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Programming Interface Information:
This information is NOT intended to be used as Programming Interfaces of z/VM. |
BMSBK
Control Block Contents
BMSBK DSECT
Cross Reference (Contains links to field and bit definitions)
BMSBK Prolog
NAME : HCPBMSBK
DESCRIPTION: BUFFER MANAGEMENT SERVICE CONTROL BLOCK
DSECT : BMSBK
FUNCTION : CONTAINS THE CURRENT STATUS OF A BUFFER
MANAGEMENT TASK
LOCATED BY : USAGE DEPENDENT
CREATED BY : HCPBMSIN
DELETED BY : HCPBMSTM
EMPLOYED BY- HCPBMSRA : WHEN RETURNING A LIST OF BUFFERS
TO THE AVAILABLE STACK
HCPBMSOA : WHEN OBTAINING A LIST OF BUFFERS
FROM THE AVAILABLE STACK
HCPBMSGA : WHEN GETTING A BUFFER FROM THE
AVAILABLE STACK
HCPBMSAA : WHEN ADDING BUFFERS FROM FREE
STORAGE TO THE AVAILABLE STACK
HCPBMSSA : WHEN RETURNING BUFFERS FROM THE
AVAILABLE STACK TO FREE STORAGE
HCPBMSPP : WHEN PUTTING A BUFFER ON THE
PENDING QUEUE
HCPBMSOP : WHEN OBTAINING A LIST OF BUFFERS
FROM THE PENDING QUEUE
HCPBMSQP : WHEN GETTING THE COUNT OF BUFFERS
ON THE PENDING QUEUE
COMMENTS : SERIALIZED BY THE BMSBK LOCK, BMSLOCK FOR
ALL ENTRY POINTS EXCEPT HCPBMSIN.
BMSBK Control Block Content
BMSBK DSECT
Hex Dec Type/Val Lng Label (dup) Comments
---- ---- --------- ---- -------------- --------
0000 0 Structure BMSBK BUFFER MANAGEMENT SERVICE CONTROL
BLOCK
BUFFER MANAGEMENT SERVICE INFORMATION
0000 0 Signed 4 * (0) BLOCK STATUS
0000 0 Bitstring 1 BMSSTTYP FREE STORAGE INDICATOR
.... ...1 BMSPAG X'01' BMSBK IS A REAL FRAME
(PAGE)
.... ..1. BMSFRE X'02' BMSBK IS FROM FREE STORAGE
.... .1.. BMSFIXED X'04' BMSBK DESCRIBES A BUFFER
POOL THAT IS A FIXED SIZE (USED
BY TRSAVE FOR CP ON)
.... 1... BMSDFRIO X'08' Wrap buffers in real
storage
0001 1 Bitstring 1 * RESERVED FOR FUTURE USE
0002 2 Signed 2 BMSDWSZ DOUBLE WORD SIZE OF BLOCK THIS
FIELD IS ONLY USED WHEN THIS
BLOCK IS CREATED FORM FREE
STORAGE
0004 4 Signed 4 BMSBUFCT COUNT OF TOTAL BUFFERS Within a
chain of BMSBKs, this field is
only meaningful in the first
BMSBK of the chain
0008 8 Signed 4 BMSAVBCT COUNT OF AVAILABLE BUFFERS Within
a chain of BMSBKs, this field is
only meaningful in the first
BMSBK of the chain
000C 12 Signed 4 BMSPDBCT COUNT OF PENDING BUFFERS Within a
chain of BMSBKs, this field is
only meaningful in the first
BMSBK of the chain
0010 16 Signed 4 BMSRTBCT COUNT OF BUFFERS RETURNED TO THE
AVAILABLE STACK
0014 20 Signed 4 * RESERVED FOR FUTURE USE
BUFFER LOCKS
0018 24 Dbl-Word 8 BMSLOCK (3) SPIN LOCK FOR THE BMS BLOCK
Within a chain of BMSBKs, this
field is only meaningful in the
first BMSBK of the chain
AVAILABLE BUFFERS
0030 48 Address 4 BMSAVPTR POINTER TO AVAILABLE BUFFERS
Within a chain of BMSBKs, this
field is only meaningful in the
first BMSBK of the chain
PENDING BUFFERS
0034 52 Address 4 BMSNEXT Pointer to next BMSBK in chain of
BMSBKs
0038 56 Address 4 BMSBMOFF Pointer to BMSBK which contains
oldest pending buffer. Within a
chain of BMSBKs, this field is
only meaningful in the first
BMSBK of the chain
003C 60 Address 4 BMSBMON Pointer to BMSBK which contains
next available slot. Within a
chain of BMSBKs, this field is
only meaningful in the first
BMSBK of the chain
0040 64 Address 4 BMSPDOFF POINTER TO FIRST BUFFER ON THE
QUEUE
0044 68 Address 4 BMSPDON POINTER TO NEXT AVAILABLE SLOT ON
THE QUEUE
0048 72 Address 4 BMSPDLST ADDRESS OF THE LAST SLOT IN THE
ARRAY
0000000A BMSHSIZE (*-BMSBK+7)/8 SIZE OF THE BMS
HEADER
004C 76 Address 4 BMSPDST (0) START OF VARIABLE LENGTH DATA
ARRAY OF POINTERS TO PENDING
BUFFERS 1000 BUFFERS ARE MAXIMUM
BMSBK Storage Layout
*** BMSBK - BUFFER MANAGEMENT SERVICE CONTROL BLOCK
*
* +------+------+-------------+---------------------------+
* 0 |:STTYP|//////| BMSDWSZ | BMSBUFCT |
* +------+------+-------------+---------------------------+
* 8 | BMSAVBCT | BMSPDBCT |
* +---------------------------+---------------------------+
* 10 | BMSRTBCT |///////////////////////////|
* +---------------------------+---------------------------+
* 18 | |
* = BMSLOCK =
* | |
* +---------------------------+---------------------------+
* 30 | BMSAVPTR | BMSNEXT |
* +---------------------------+---------------------------+
* 38 | BMSBMOFF | BMSBMON |
* +---------------------------+---------------------------+
* 40 | BMSPDOFF | BMSPDON |
* +---------------------------+---------------------------+
* 48 | BMSPDLST |
* +---------------------------+
*
*** BMSBK - BUFFER MANAGEMENT SERVICE CONTROL BLOCK
BMSBK Cross Reference
Symbol Dspl Value -------------- ---- ----- BMSAVBCT 0008 BMSAVPTR 0030 BMSBMOFF 0038 BMSBMON 003C BMSBUFCT 0004 BMSDFRIO 0000 08 BMSDWSZ 0002 BMSFIXED 0000 04 BMSFRE 0000 02 BMSHSIZE 0048 0000000A BMSLOCK 0018 BMSNEXT 0034 BMSPAG 0000 01 BMSPDBCT 000C BMSPDLST 0048 BMSPDOFF 0040 BMSPDON 0044 BMSPDST 004C BMSRTBCT 0010 BMSSTTYP 0000
Copyright IBM Corporation, 1990, 2001