1. A method, comprising: detecting, by a hypervisor of a host computer system, a task switch event associated with a first virtual processor running on a physical processor of the host computer system; testing a polling flag residing in a memory accessible by guest software running on the first virtual processor, wherein a polling state of the polling flag indicates that the first virtual processor is monitoring modifications to a memory region comprising a waiting task flag, wherein a state of the waiting task flag indicates that a task has been queued for the first virtual processor; preventing a second virtual processor from transmitting a notification to the first virtual processor via a memory monitoring mechanism, by setting the polling flag to a non-polling state, wherein testing the polling flag and setting the polling flag to the non-polling state is performed in an atomic operation; and processing the task switch event by scheduling the second virtual processor to run on the physical processor.