Programming Interface Information:
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SUBBK
Control Block Contents
SUBBK DSECT
Cross Reference (Contains links to field and bit definitions)
SUBBK Prolog
Name : HCPSUBBK Description: Subpool Data Area Block DSECT : SUBBK Function : Maps each of the free storage subpool data area elements. Created by : Never allocated Deleted by : Never deallocated Notes : This DSECT is used to map the free storage subpool data area groups located in HCPRSM. Specifically, HCPRSMSS (regular free storage subpools) and HCPRSMVT (V=R free storage subpools). Each data area group consists of multiple data area elements.
SUBBK Control Block Content
SUBBK DSECT
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure SUBBK Subpool Data Area Block Format 0 ("old style") SUBBK format used for subpools for the following types of subpooled free storage: - V=R free storage (HCPFRFV* entry points, HCPVRS) - Virtual Free Storage (HCPVFM) - Aligned Free Storage (HCPAFS) - Verifiable Free Storage (HCPVCB) 0000 0 Signed 4 SUBLOCK Subpool lock word 0004 4 Signed 4 SUBSIZE Integral size (in DWDS) of subpool block including FRERECL 0008 8 Address 4 SUBANCH Pointer to first FRMTE for subpooled free storage, or 1st available block for V=R 000C 12 Signed 4 SUBRCNT Count of requests this size 0010 16 Signed 4 SUBODWD Count of DWD currently in use (multiple of SUBSIZE) 0014 20 Signed 4 SUBCDWD Count of DWDS now on chain 0018 24 Signed 4 SUBUDWD Count of actual DWD usage (does not include internal fragmentation) 001C 28 Signed 4 * Reserved for IBM use 0020 32 Signed 4 * Reserved for IBM use 00000024 SUBESZ *-SUBBK Size of one subpool entry Format 1 ("new/fast style") SUBBK format used for standard short term free storage, including "fast allocated" free storage control blocks. 0000 0 Bitstring 1 SUBTSLK Subpool lock byte 0001 1 Bitstring 1 * Reserved for IBM use 0002 2 Signed 2 SUBBSIZE Size in bytes (including header/trailer) of each block on this subpool 0004 4 Signed 2 SUBMAXBS Maximum number of blocks that fit in one frame 0006 6 Signed 2 SUBMTFCT Count of frames on SUBMTFTE empty frame queue for this subpool Notes : The following three fields (SUBFRETS, SUBBLOCK, and SUBTOTRQ) must remain contiguous and in order, as there is performance sensitive code in the free storage allocation and deallocation paths which references two adjacent fields (SUBBLOCK and SUBTOTRQ for allocation, SUBFRETS and SUBBLOCK for deallocation) with a single STM instruction 0008 8 Signed 4 SUBFRETS Total count of returns to this free storage subpool 000C 12 Signed 4 SUBBLOCK Anchor for blocks on this subpool 0010 16 Signed 4 SUBTOTRQ Total count of requests against this subpool SUBFRETS and SUBBLOCK remain contiguous SUBBLOCK and SUBTOTRQ remain contiguous 0014 20 Signed 4 SUBMTFTE FRMTE address of 1st empty frame on queue. FFS mark end of chain. 0018 24 Signed 4 SUBCLCTP Collection pile 001C 28 Signed 4 SUBXTNCT Count of extends 0020 32 Signed 2 SUBFRMCT Count of frames on pool 0022 34 Signed 2 SUBINUSE Count of blocks in use on this subpool 00000024 SUBNEXT * Address of next SUBBK 00000024 SUBSSZ *-SUBBK Size of one standard short term free storage SUBBK entry 00000002 SUBOFFSH 2 Number of bits to shift a subpool number to get the index into the HCPFRESO SUBBK offsets table for the subpool's SUBBK Format 1 SUBBKs are the same length
SUBBK Storage Layout
*** SUBBK - Subpool Data Area Block * * +---------------------------+---------------------------+ * 0 | SUBLOCK | SUBSIZE | * +---------------------------+---------------------------+ * 8 | SUBANCH | SUBRCNT | * +---------------------------+---------------------------+ * 10 | SUBODWD | SUBCDWD | * +---------------------------+---------------------------+ * 18 | SUBUDWD |///////////////////////////| * +---------------------------+---------------------------+ * 20 |///////////////////////////| 24 * +---------------------------+ * *** SUBBK - Subpool Data Area Block *** Overlay for SUBLOCK in SUBBK * * +------+------+-------------+-------------+-------------+ * 0 |:TSLK |//////| SUBBSIZE | SUBMAXBS | SUBMTFCT | * +------+------+-------------+-------------+-------------+ * 8 | SUBFRETS | SUBBLOCK | * +---------------------------+---------------------------+ * 10 | SUBTOTRQ | SUBMTFTE | * +---------------------------+---------------------------+ * 18 | SUBCLCTP | SUBXTNCT | * +-------------+-------------+---------------------------+ * 20 | SUBFRMCT | SUBINUSE | 24 * +-------------+-------------+ * *** Overlay for SUBLOCK in SUBBK
SUBBK Cross Reference
Symbol Dspl Value -------------- ---- ----- SUBANCH 0008 SUBBLOCK 000C SUBBSIZE 0002 SUBCDWD 0014 SUBCLCTP 0018 SUBESZ 0020 00000024 SUBFRETS 0008 SUBFRMCT 0020 SUBINUSE 0022 SUBLOCK 0000 SUBMAXBS 0004 SUBMTFCT 0006 SUBMTFTE 0014 SUBNEXT 0022 00000024 SUBODWD 0010 SUBOFFSH 0022 00000002 SUBRCNT 000C SUBSIZE 0004 SUBSSZ 0022 00000024 SUBTOTRQ 0010 SUBTSLK 0000 SUBUDWD 0018 SUBXTNCT 001C
Last updated on 5 Jun 2001 at 16:50:36 EDT.
Copyright IBM Corporation, 1990, 2001