●●● ●●●● 6.2 The Critical-Section Problem :: ●●●0 To solve the critical-section problem ●●●● o Criteria for the critical section problem solution Mutual exclusion(互斥) If process Pi is executing in its critical section, then no other processes can be executing in their critical sections of accessing the same shared data Progress(推进、空闲让进) If no process is executing in its critical section and there exist some processes that wish to enter their critical section The selection of the processes that will enter the critical section next cannot be postponed infinitely Bounded Waiting(有限等待) a bound must exist on the number of times for the processes waiting for entering their critical sections12 6.2 The Critical-Section Problem ⚫ To solve the critical-section problem ⚫ Criteria for the critical section problem solution ⚫ Mutual Exclusion（互斥） ▪ If process Pi is executing in its critical section, then no other processes can be executing in their critical sections of accessing the same shared data. ⚫ Progress（推进、空闲让进） ▪ If no process is executing in its critical section and there exist some processes that wish to enter their critical section ▪ The selection of the processes that will enter the critical section next cannot be postponed infinitely. ⚫ Bounded Waiting（有限等待） ▪ A bound must exist on the number of times for the processes waiting for entering their critical sections