NAME : HCPPPDBK
DESCRIPTION: Paged PGMBK Data block
DSECT : PPDBK
FUNCTION : A PPDBK contains information required to find
and process an STE corresponding to a paged
PGMBK (PTRM page) which has been paged to DASD.
LOCATED BY : The PPDBK address is saved in the invalid PTRM PTE
for PTRM pages (paged PGMBKs) that reside on DASD.
The address is saved in a hashed format so that the
Invalid and Page Protect bits of the PTRM PTE are
left undisturbed; HCPISTEA macro is used to insert
the PPDBK address into the PTRM PTE, HCPGSTEA macro
is used to extract the PPDBK address from the PTRM
CREATED BY : HCPHRPOP when a PTRM page is invalidated,
in preparation for the PTRM page (pageable PGMBK)
potentially being paged to DASD.
HCPPMPRB when a PTRM page (paged PGMBK) is
migrated from expanded storage to DASD.
HCPHRUSM when processing a segment table
relocation, and a PTRM page (pageable PGMBK) on
DASD, but without a PPDBK address in the PTRM PTE,
DELETED BY : HCPHTUPF when a PTRM page (paged PGMBK)
is read in from DASD.
HCPPTAQA when a PTRM page (pageable PGMBK) is paged
to expanded storage instead of DASD.
Serialized by PTRM PTE serialization, though to use
or change the PPDSTE field, (at least) a share of
VMDPTIL on the virtual configuration that owns
the corresponding segment table entry is required,
to serialize against concurrent destructive changes
to the segment table (such as segment table relocate
for resize during NSS/DCSS imbed/unimbed).