Linux® Kernel Primer, The: A Top-Down Approach for x86 and PowerPC Architectures

Chapter 7. Scheduling and Kernel Synchronization

In this chapter

• 7.1 Linux Scheduler 375

• 7.2 Preemption 405

• 7.3 Spinlocks and Semaphores 409

• 7.4 System Clock: Of Time and Timers 411

• Summary 418

• Exercises 419

The Linux kernel is a multitasking kernel, which means that many processes can run as if they were the only process on the system. The way in which an operating system chooses which process at a given time has access to a system's CPU(s) is controlled by a scheduler.

The scheduler is responsible for swapping CPU access between different processes and for choosing the order in which processes obtain CPU access. Linux, like most operating systems, triggers the scheduler by using a timer interrupt. When this timer goes off, the kernel needs to decide ...