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 RELOCATION CONSIDERATIONS : None 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' BMSPAG BMSBK IS A REAL FRAME (PAGE) .... ..1. BMSFRE X'02' BMSFRE BMSBK IS FROM FREE STORAGE .... .1.. BMSFIXED X'04' BMSFIXED BMSBK DESCRIBES A BUFFER POOL THAT IS A FIXED SIZE (USED BY TRSAVE FOR CP ON) .... 1... BMSDFRIO X'08' BMSDFRIO 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 (6) 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 0048 72 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 004C 76 Address 4 BMSNEXT Pointer to next BMSBK in chain of BMSBKs 0050 80 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 0054 84 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 0058 88 Address 4 BMSPDOFF POINTER TO FIRST BUFFER ON THE QUEUE 005C 92 Address 4 BMSPDON POINTER TO NEXT AVAILABLE SLOT ON THE QUEUE 0060 96 Address 4 BMSPDLST ADDRESS OF THE LAST SLOT IN THE ARRAY 0000000D BMSHSIZE (*-BMSBK+7)/8 SIZE OF THE BMS HEADER 0064 100 Address 4 BMSPDST (0) START OF VARIABLE LENGTH DATA ARRAY OF POINTERS TO PENDING BUFFERS See PERBMS in HCPEQUAT for maximum number of buffers per BMSBK. Verify that size of BMSBK doesn't exceed 1 page.
BMSBK Storage Layout
*** BMSBK - BUFFER MANAGEMENT SERVICE CONTROL BLOCK * * +------+------+-------------+---------------------------+ * 0 |:STTYP|//////| BMSDWSZ | BMSBUFCT | * +------+------+-------------+---------------------------+ * 8 | BMSAVBCT | BMSPDBCT | * +---------------------------+---------------------------+ * 10 | BMSRTBCT |///////////////////////////| * +---------------------------+---------------------------+ * 18 | | * = BMSLOCK = * | | * +---------------------------+---------------------------+ * 48 | BMSAVPTR | BMSNEXT | * +---------------------------+---------------------------+ * 50 | BMSBMOFF | BMSBMON | * +---------------------------+---------------------------+ * 58 | BMSPDOFF | BMSPDON | * +---------------------------+---------------------------+ * 60 | BMSPDLST | * +---------------------------+ * *** BMSBK - BUFFER MANAGEMENT SERVICE CONTROL BLOCK
BMSBK Cross Reference
Symbol Dspl Value -------------- ---- ----- BMSAVBCT 0008 BMSAVPTR 0048 BMSBMOFF 0050 BMSBMON 0054 BMSBUFCT 0004 BMSDFRIO 0000 08 BMSDWSZ 0002 BMSFIXED 0000 04 BMSFRE 0000 02 BMSHSIZE 0060 0000000D BMSLOCK 0018 BMSNEXT 004C BMSPAG 0000 01 BMSPDBCT 000C BMSPDLST 0060 BMSPDOFF 0058 BMSPDON 005C BMSPDST 0064 BMSRTBCT 0010 BMSSTTYP 0000
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