Browse Prior Art Database

Method for Rapid Establishment of Central-to-Virtual Storage Bindsfile

IP.com Disclosure Number: IPCOM000104971D
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 88K

Publishing Venue

IBM

Related People

Manners, DC: AUTHOR [+2]

Abstract

Disclosed is a method that provides for the rapid establishment and corresponding relinquishing of central-to-virtual storage binds for programs that must or may run with I/O and external interrupts enabled while the bind is outstanding. The essence of this invention is to utilize the LOCKPAGE instruction to establish a temporary storage bind to prevent page replacement while the related system control structures are updated to reflect a traditionally established storage bind.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Method for Rapid Establishment of Central-to-Virtual Storage Bindsfile

      Disclosed is a method that provides for the rapid establishment
and corresponding relinquishing of central-to-virtual storage binds
for programs that must or may run with I/O and external interrupts
enabled while the bind is outstanding.  The essence of this invention
is to utilize the LOCKPAGE instruction to establish a temporary
storage bind to prevent page replacement while the related system
control structures are updated to reflect a traditionally established
storage bind.

      Authorized programs executing in an MVS/ESA* environment
frequently require the inhibition of page replacement of pageable
virtual storage.  For example, a program intending to write data from
pageable virtual storage to disk must first bind the central storage
backing the affected virtual locations to the virtual address(es) for
the duration of the I/O.

      Traditionally, such binds are accomplished solely through
calling a system service.  The essential mechanics of this
traditional bind service are:

1.  establish its necessary execution environment,
2.  obtain serialization at an address space granularity,
3.  perform any necessary manipulation of the virtual storage to
    satisfy central storage attribute requirements,
4.  track this instance of a central-to-virtual storage bind in
    system software control structures.

The user of this traditional bind service is required to know whether
the virtual storage is resident in a data space or not in a data
space.

      LOCKPAGE is a hardware instruction that interprets the Access
Register Translation (ART) and Dynamic Address Translation (DAT)
paths of a virtual address to establish a central-to-virtual storage
bind at a 4K (page) granularity via a single indicator in the lowest
level of the architected translation control structures.  This
differs significantly, from a functional perspective, from previous
storage binding services in that:

1.  the bind is reflected only in the architected control structure,
2.  there is no yield of control to the operating system to establish
    the bind.

Because of these differences, LOCKPAGE is not permitted during
windows of CPU enablement.

      In MVS, central storage is divided into 4K sections called
frames.  Each frame is represented b...