Obtaining CSM resource statistics

An application can request the address of information required to monitor usage of CSM resources such as ECSA, data space and fixed storage. The address of this information is returned on the STATAREA parameter when the following macroinstructions are issued:

The application can request the address of the resource statistics area during initialization processing and can reference this area to obtain resource statistics throughout normal processing.

For each resource type, the following bits are defined:

Critical: Indicates that CSM storage usage is at 90% of defined limits or higher.
Constrained: Indicates that CSM storage usage is higher than 80% of defined limits and is approaching the constrained level (85% of defined limits). If this bit is set, the application should determine if the critical bit is also set.

Note: If neither bit is set, the resource usage is considered to be normal.

Restriction: GET_BUFFER requests that exceed the storage available in CSM are rejected.

CSM users should monitor CSM storage use and take action to prevent critical shortages that might jeopardize the application or system operation. Actions might include:

Freeing buffers that are no longer needed
Selecting a different storage source for buffer pools
Limiting usage of fixed storage

IVTSTATA DSECT maps CSM resource statistics information. See CSM resource status area (IVTSTATA).