Subclasses

The system administrator or a superclass administrator can define up to 61 subclasses.

In addition, two special subclasses, Default and Shared, are always defined.

Default subclass

Is the default subclass and is always defined. All processes that are not automatically assigned to a specific subclass of the superclass are assigned to the Default subclass. You can also assign other processes to the Default subclass by providing specific assignment rules.

Shared subclass

Receives all the memory pages that are used by processes in more than one subclass of the superclass. Included are pages in shared memory regions and pages in files that are used by processes in more than one subclass of the same superclass. Shared memory and files that are used by multiple processes that all belong to a single subclass are associated with that subclass. Only when a process from a different subclass of the same superclass accesses the shared memory region or file are the pages placed in the Shared subclass of the superclass. There are no processes in the Shared subclass. This subclass can have only physical memory shares and limits applied to it, and it cannot have shares or limits for the other resource types or assignment rules specified. Whether a memory segment shared by processes in different subclasses of the same superclass is classified into the Shared subclass or remains in its original subclass depends on the value of the localshm attribute of the original subclass.