Determining when it is safe to use scheduler lock-acquiring wakeups to defer quiescent states in real-time preemptible read-copy update

A system, comprising:

• a plurality of processors;
• a memory coupled to the processors, the memory including a computer readable storage medium tangibly embodying at least one program of instructions executable by the processors to perform operations comprising:
• determining whether a deferred quiescent-state reporting request that defers the reporting of a read-copy update (RCU) quiescent state on behalf of a target computer task is warranted;
• in response to the deferred quiescent-state reporting request being warranted, determining whether a previous deferred quiescent-state reporting request on behalf of the target computer task remains pending;
• and
• issuing a request for deferred quiescent-state report processing that reports a deferred quiescent state, the request for deferred quiescent-state report processing being issued in a manner selected according to a result of the determining whether a previous deferred quiescent-state reporting request remains pending.

A computer program product, comprising:

• one or more computer readable data storage media;
• program instructions stored on the one or more computer readable data storage media for programming a data processing platform having a plurality of processors to perform operations comprising:
• determining whether a deferred quiescent-state reporting request that defers the reporting of a read-copy update (RCU) quiescent state on behalf of a target computer task is warranted;
• in response to the deferred quiescent-state reporting request being warranted, determining whether a previous deferred quiescent-state reporting request on behalf of the target computer task remains pending;
• and
• issuing a request for deferred quiescent-state report processing that reports a deferred quiescent state, the request for deferred quiescent-state report processing being issued in a manner selected according to a result of the determining whether a previous deferred quiescent-state reporting request remains pending.