1. A method in a data processing system for processing a service request, the method comprising: obtaining by a service partition of the data processing system a service request from a logical partition of the data processing system, the logical partition and the service partition each having been created by and executing above a hypervisor of the data processing system, and the hypervisor having assigned a processor quantum to the logical partition; processing the service request by the service partition utilizing the processor quantum assigned to the logical partition by the hypervisor and donated by the logical partition to the service partition; controlling by the logical partition scheduling of the service partition, the controlling comprising queuing the service request at the logical partition until the logical partition decides to schedule execution of the service request by the service partition; and at least one of: (i) monitoring by the service partition for expiration of the processor quantum prior to completion of processing of the service request, and when detected, automatically posting a partition busy interrupt signal by the hypervisor for the logical partition, saving service partition state information by the hypervisor, and dispatching the logical partition to process the partition busy interrupt signal, wherein processing the partition busy interrupt signal by the logical partition comprises determining whether to currently schedule the service request for further execution by the service partition; or (ii) monitoring by the hypervisor for receipt of an interrupt or timeout parameter requiring servicing by the service partition on behalf of the logical partition, and when detected, automatically posting a partition busy interrupt signal by the hypervisor for the logical partition, saving service partition state information by the hypervisor, and dispatching the logical partition to process the partition busy interrupt signal, wherein processing the partition busy interrupt signal comprises determining by the logical partition whether to currently schedule the service partition for processing of the interrupt or timeout parameter requiring servicing, or whether to delay processing of the interrupt or timeout parameter requiring servicing, pending execution of higher priority work by the logical partition.