1. A method for facilitating selective prefetching based on system resource availability in a computer system, comprising: while executing instructions in a processor, monitoring the availability of at least one system resource and dynamically adjusting an availability indicator for the system resource based on the current availability of the system resource; upon executing a prefetch instruction which generates a prefetch request that involves the system resource, checking the availability indicator; and if the availability indicator indicates that the system resource is not sufficiently available, terminating the prefetch request, whereby terminating the prefetch request prevents prefetch requests from overwhelming the system resource.