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Programming Interface Information:
This information is NOT
intended to be
used as Programming Interfaces of VM/ESA. It is to be used for diagnosis only. |
LCKBK
Cross Reference (Contains links to field and bit definitions)
LCKBK Prolog
NAME : HCPLCKBK
DESCRIPTION: LOCK BLOCK
DSECT : LCKBK
FUNCTION : HCPLCKBK IS USED TO SYNCHRONIZE EXECUTION FOR SECTIONS
OF NONREENTERABLE CODE. EACH SUCH SECTION OF CODE HAS
ITS OWN UNIQUE 8 BYTE IDENTIFIER (NAME) WHICH IS PASSED
TO THE LOCKING ROUTINES AS AN ARGUMENT. THIS IDENTIFIER
IS SAVED IN 'LCKNAME'. A TASK THAT ATTEMPTS TO GET A
LOCK THAT IS ALREADY HELD BY ANOTHER TASK IS FORCED TO
WAIT UNTIL THE EARLIER TASK RELEASES THE LOCK. WHILE THE
TASK IS WAITING, IT IS REPRESENTED BY A CPEBK THAT
IS TEMPORARILY CHAINED OFF OF 'LCKQUE'. WHEN THE TASK
HOLDING THE LOCK RELEASES IT, THE CPEBK REPRESENTING THE
WAITING TASK IS STACKED SO THAT THE WAITING TASK RESUMES
EXECUTION.
LOCATED BY : SYSLOKQ LOCK BLOCK ANCHOR: POINTS TO CHAIN OF LOCK BLOCKS.
LCKNEXT POINTER TO NEXT LOCK BLOCK IN CHAIN.
CREATED BY : HCPLOC WHEN A LOCK IS REQUESTED TO BE PUT ON A RESOURCE
AND THAT RESOURCE IS NOT CURRENTLY LOCKED.
DELETED BY : HCPLOC WHEN A TASK RELEASES THE LOCK AND THERE ARE NO
OTHER TASKS QUEUED ON THE LOCK.
LCKBK Control Block Content
LCKBK DSECT
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure LCKBK LOCK BLOCK 0000 0 Signed 4 LCKNEXT POINTER TO THE NEXT LOCK BLOCK 0004 4 Signed 4 LCKQUE POINTER TO CPEXBLOK QUEUE 0008 8 Dbl-Word 8 LCKNAME (0) LOCK SYMBOL 0008 8 Signed 4 LCKNAM1 FIRST FOUR BYTES OF SYMBOL 000C 12 Signed 4 LCKNAM2 SECOND FOUR BYTES OF SYMBOL 0010 16 Address 4 LCKIDR11 R11 of lock requestor 0014 20 Address 4 LCKIDR14 R14 of lock requestor 0018 24 Dbl-Word 8 LCKQQTOD TOD saved at last enqueue/dequeue. (Only stamped if there's a queue for this symbolic defer lock.) 0020 32 Signed 4 LCKDQLEN Current length of queue waiting for this symbolic defer lock. (Note: We could shorten LCKDQLEN to a halfword and regain 2 bytes.) 0024 36 Signed 4 LCKDYTOD TOD saved at start of last "delay" period. It's the time the lock was last granted (if it had a queue at that time) or the time at which the queue size last changed from 0 to 1. Units are TOD with bits 32-63 discarded. 00000005 LCKSIZE (*-LCKBK+7)/8 LOCK BLOCK SIZE IN DWORDS
LCKBK Storage Layout
*** LCKBK - LOCK BLOCK * * +---------------------------+---------------------------+ * 0 | LCKNEXT | LCKQUE | * +---------------------------+---------------------------+ * 8 | LCKNAM1 | LCKNAM2 | * +---------------------------+---------------------------+ * 10 | LCKIDR11 | LCKIDR14 | * +---------------------------+---------------------------+ * 18 | LCKQQTOD | * +---------------------------+---------------------------+ * 20 | LCKDQLEN | LCKDYTOD | * +---------------------------+---------------------------+ * 28 * *** LCKBK - LOCK BLOCK
LCKBK Cross Reference
(contains links to field and bit definitions)Symbol Dspl Value -------------- ---- -----LCKDQLEN 0020
LCKDYTOD 0024
LCKIDR11 0010
LCKIDR14 0014
LCKNAME 0008
LCKNAM1 0008
LCKNAM2 000C
LCKNEXT 0000
LCKQQTOD 0018
LCKQUE 0004
LCKSIZE 0024 00000005
Last updated on 3 Aug 1999 at 12:08:11 EDT.
Copyright IBM Corporation, 1990, 1999