Kernel-Managed Swap Facility (KMSF) Manual

Introduction
Kernel-Managed Swap Facility (KMSF) Manual—425824-005
1-3
KMSF and Users
configured threshold and to changes in KMSF configuration. Managing KMS space is
described in Section 3, Managing KMS Files.
KMSF and Users
When a user starts a process, KMSF provides the swap space that the process
requires at process creation. User control over certain aspects of swap files is limited,
because KMS files provide swap space for multiple processes:
•
In most cases, users cannot decide where data is swapped. The user can specify
the location of the swap space for user-allocated segments only. Otherwise, data is
swapped to whatever KMS file or files are available for the processor in which the
process is running.
•
Only super-group users (255, n) can add, alter, start, stop, or delete KMS files. For
more detailed information about security, see NSKCOM Security on page 3-3.
You do not need to change the code of applications to use KMSF.
Components of Managing Virtual Memory
Using KMSF
Kernel-managed swapping is implemented through the following major components:
•
The KMSF, which reads the KMS configuration file, controls the swap files and
provides, resizes, and receives back swap space reservations and swap space
allocations.
•
The memory management software, which acquires, requests resizes of, and
returns swap space reservations, and requests and returns swap space
allocations.
•
NSKCOM, the operating system utility program used to configure and manage
KMS files. NSKCOM is the user interface to the KMSF and is used to modify the
ZSYSCFG file.
•
ZSYSCFG, the configuration file specifying the names and usage of KMS files.
•
The kernel-managed swap files (KMS files).
Figure 1-1 on page 1-4 illustrates the relationships between these components.