chapter4.md

4 Main Runqueue

The main per-CPU runqueue data structure is defined in kernel/sched.c. It keeps track of all runnable tasks assigned to a particular CPU and manages various scheduling statistics about CPU load or scheduling domains for load balancing. Furthermore it has:

• a lock to synchronize scheduling operations for this CPU

  raw_spinlock_t lock;
  

• pointers to the task_structs of the currently running, the idle and the stop task

  struct task_struct *curr, *idle, *stop;
  

• runqueue data structures for fair and real time scheduling classes

  struct cfs_rq cfs;
  struct rt_rq rt;
  

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4. 主运行队列

主运行队列在每个 CPU 上都有一份，数据结构定义在 kernel/sched.c。它记录了特定 CPU 上所有的可运行的任务，并且还管理和每个处理器负载或域负载相关的不同调度的统计信息。更进一步来说，它包括下面几项：

• 一个锁，用来同步当前 CPU 的调度操作

  raw_spinlock_t lock;
  

• 分别指向当前运行的任务、空闲任务、停止任务的 task_struct 结构体指针

  struct task_struct *curr, *idle, *stop;
  

• 公平调度和实时调度类的运行队列数据结构

  struct cfs_rq cfs;
  struct rt_rq rt;