1. A method of facilitating determination of scheduling priorities of jobs in a processing environment, said method comprising: obtaining an indication of an amount of a resource that is available in the processing environment, this amount being independent of consumption of the resource and subject to an exponential decay function; dividing the amount of the resource among a plurality of usage shares; allocating one or more usage shares of the resource to a user entity of the processing environment, said one or more usage shares being at least a portion of a plurality of usage shares defined for the processing environment based on a total amount of the resource available in the processing environment and the one or more usage shares representing an amount of the resource available for use by the user entity independent of an amount of the resource consumed by other user entities of the processing environment, wherein the one or more usage shares allocated to the user entity represents a portion of the total amount of the resource available in the processing environment; assigning a job scheduling priority to a job of the user entity to be executed, said job scheduling priority being based on how many usage share have been allocated to the user entity and how many usage shares have been used by the user entity and is independent of historic usage of the resource by other user entities; and collecting resource usage data, wherein the collecting comprises accumulating data associated with usage of the resource by the user entity, said accumulated data including contribution from past resource usage by the user entity, and wherein a decay function is applied at least once during the accumulating.