AIX 5L Problem Determination - IBM Redbooks

Superclasses
A superclass is a class with subclasses associated with it. No process can
belong to the superclass without also belonging to a subclass, either predefined
or user defined. A superclass has a set of class assignment rules that determines
which processes will be assigned to it. A superclass also has a set of resource
limitation values and resource target shares that determine the amount of
resources that can be used by processes belonging to it. These resources will be
divided among the subclasses based on the resource limitation values and
resource target shares of the subclasses.
Up to 27 superclasses can be defined by the system administrator. In addition,
five superclasses are automatically created to deal with processes, memory, and
CPU allocation, as follows:
► Default superclass: The default superclass is named Default and is always
defined. All non-root processes that are not automatically assigned to a
specific superclass will be assigned to the Default superclass. Other
processes can also be assigned to the Default superclass by providing
specific assignment rules.
► System superclass: This superclass has all privileged (root) processes
assigned to it if they are not assigned by rules to a specific class, plus the
pages belonging to all system memory segments, kernel processes, and
kernel threads. Other processes can also be assigned to the System
superclass. The default is for this superclass to have a memory minimum limit
of one percent.
► Shared superclass: This superclass receives all the memory pages that are
shared by processes in more than one superclass. This includes pages in
shared memory regions and pages in files that are used by processes in more
than one superclass (or in subclasses of different superclasses). Shared
memory and files used by multiple processes that belong to a single
superclass (or subclasses of the same superclass) are associated with that
superclass. The pages are placed in the Shared superclass only when a
process from a different superclass accesses the shared memory region or
file. This superclass can have only physical memory shares and limits applied
to it. It cannot have shares or limits for the other resource types, subclasses,
or assignment rules specified. Whether a memory segment shared by the
processes in the different superclasses is classified into the Shared
superclass, or remains in the superclass it was initially classified into depends
on the value of the localshm attribute of the superclass the segment was
initially classified into.
► Unclassified superclass: The processes in existence at the time WLM is
started are classified according to the assignment rules of the WLM
configuration being loaded. During this initial classification, all the memory
pages attached to each process are charged either to the superclass the
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