Operating Systems: Concurrent and Distributed Software Design

17.2. Composite operations in main memory

Consider a number of processes sharing an address space and assume that a number of monitors (or objects with synchronized methods) are available to them as the means by which shared data is protected or shared resources are allocated exclusively. The specification of the operations may be such that a process may acquire a monitor (or object) lock, then, while executing an operation of the monitor (or a synchronized method), make a nested call to another monitor (or object) (Figure 17.3). Process A has invoked operation W, assumed to be a monitor operation (or synchronized method), and has made a nested invocation of operation Y in another monitor. Process B has invoked X and made a nested invocation ...