Working set adjustment in a managed environment

A computer program product for working set adjustment, the computer program product comprising:

• a computer readable storage device containing computer executable program code stored thereon, the computer executable program code comprising:
• computer executable program code for receiving a request to use less heap memory than an original maximum forming a new maximum;
• computer executable program code for determining whether a garbage collection will move objects in response to the request;
• computer executable program code for adding a first callback triggered by initiation of the garbage collection that will move objects, responsive to a determination that the garbage collection will move objects;
• computer executable program code for invoking a handler for the first callback notifying a memory manager to free objects allocated by balloon;
• computer executable program code for completing the first callback and starting the garbage collection;
• computer executable program code for invoking a handler for a second callback, which notifies the memory manager to allocate balloon objects, and frees backing memory to an operating system, the balloon objects consuming an amount of memory space equal to a remaining portion of memory necessary to return to the operating system;
• and
• computer executable program code for completing the second call back allowing the garbage collection to proceed as usual.

An apparatus for working set adjustment, the apparatus comprising:

• a communications fabric;
• a memory connected to the communications fabric, wherein the memory contains computer executable program code;
• a communications unit connected to the communications fabric;
• an input/output unit connected to the communications fabric;
• a display connected to the communications fabric;
• and
• a processor unit connected to the communications fabric, wherein the processor unit executes the computer executable program code to direct the apparatus to:
• receive a request to use less heap memory than an original maximum forming a new maximum;
• determine whether a garbage collection will move objects in response to the request;
• add a first callback triggered by initiation of the garbage collection that will move objects, responsive to a determination the garbage collection will move objects;
• invoke a handler for the first callback notifying a memory manager to free objects allocated by balloon;
• complete the first callback and starting the garbage collection;
• invoke a handler for a second callback which notifies the memory manager to allocate balloon objects and frees backing memory to an operating system, the balloon objects consuming an amount of memory space equal to a remaining portion of memory necessary to return to the operating system;
• and
• complete the second call back allowing the garbage collection to proceed as usual.