PSQBK Back to Index page
Control Block Contents 
Storage Layout 
Cross Reference (Contains links to field and bit definitions)
Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM.

  PSQBK Prolog Top of page
 DESCRIPTION: LGR PTE Serialization Queue Block
 FUNCTION   : Contains information regarding a PTE being
              processed during relocation of a guest.  PSQBKs
              represent PTEs for which:
              - PTE serialization was obtained asynchronously, or
              - PTE serialization still needs to be obtained.
 LOCATED BY : RLOPSQHD points to the head of the FIFO PSQBK queue
              RLOPSQTL points to the tail of the FIFO PSQBK queue
 SERIALIZED : RLOPSQLK field in RLOBK.  Informal spin lock.
              A PSQBK describes a block in a FIFO queue that
              represents PTEs in one of the following states
              during the walk of the PGMBKs on the source
              system during relocation of a guest:
              - PTE serialization has been asynchronously
              obtained, or
              - PTE serialization still needs to be obtained
              but has been deferred because end-to-end
              throttling is in effect based on the value of
              the RLOE2ETH throttling indicator.
              During end-to-end throttling, we must:
              - Minimize the number of PTEs on which
              serialization is held, and
              - Minimize sending further relocation data
              to the destination system
              The queue is processed by HCPRLMPQ.  For each
              block, it removes the block from the head of the
              queue and effectively rejoins the synchronous
              LGR processing by calling HCPRLTRS unless throttling
              is in effect.  In that case, it releases any PTE
              serialization held and requeues the PSQBK as a PTE
              for which serialization is not held.
              Blocks are added to the queue in the following
              - By HCPRLTPS, which is an asynchronous task
              that is stacked via HCPCALL TYPE=DEFERRED while
              walking the guest's DAT tables when SHORT PTE
              serialization is not available without deferral.
              - By HCPRLMPQ in throttling situations as previously
              - By HCPPODDQ in throttling situations to effectively
              requeue requests for PTE serialization after
              throttling is no longer in effect.
              The queue header is RLOPSQHD and the tail is
              RLOPSQTL.  End of queue is delimited by zero.
  PSQBK Control Block Content Top of page

 PSQBK DSECT Top of page
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure PSQBK LGR PTE Serialization Queue Block 0000 0 Signed 4 PSQFPNT Forward pointer 0004 4 Signed 4 PSQBPNT Backward pointer 0008 8 Dbl-Word 8 * (0) 0008 8 Dbl-Word 8 PSQPTEAD PTE Real address 0010 16 Signed 4 PSQPWIBK PWIBK address 0014 20 Bitstring 1 PSQFLAGS Flag byte 1... .... PSQHAVSR X'80' PSQHAVSR PTE Serialization held on the page represented by this PSQBK 0015 21 Bitstring 1 * (3) End of PSQBK 0018 24 Signed 4 PSQ$END (0) End of PSQBK control block 00000018 PSQLEN *-PSQBK Length of PSQBK in bytes 00000003 PSQSIZE (PSQLEN+7)/8 Size of PSQBK in doublewords
  PSQBK Storage Layout Top of page
*** PSQBK - LGR PTE Serialization Queue Block
*     +---------------------------+---------------------------+
*   0 |         PSQFPNT           |         PSQBPNT           |
*     +---------------------------+---------------------------+
*   8 |                       PSQPTEAD                        |
*     +---------------------------+------+--------------------+
*  10 |         PSQPWIBK          |:FLAGS|////////////////////|
*     +---------------------------+------+--------------------+
*** PSQBK - LGR PTE Serialization Queue Block
  PSQBK Cross Reference Top of page
Symbol         Dspl Value
-------------- ---- -----
PSQ$END        0018
PSQBPNT        0004
PSQFLAGS       0014
PSQFPNT        0000
PSQHAVSR       0014 80
PSQLEN         0018 00000018
PSQPTEAD       0008
PSQPWIBK       0010
PSQSIZE        0018 00000003
This information is based on z/VM 6.3.0 Last updated on 22 May 2013 at 13:55:18 EDT.
Copyright IBM Corporation, 1990, 2013