Question

I’ve been searching for information for a common kernel implementation of queues, that is, first-in-first-out data structures. I thought there may be one since it’s likely something that’s common to use, and there’s a standard for linked lists (in the form of the list_head structure). Is there some standard queue implementation I can’t find, or is it perhaps common practice to just use linked lists as queues and hope for the best?

Answer 1

You’re right, the Linux kernel typically uses linked lists to implement queues. This makes sense, because linked lists offer the required behavior. See this example from kernel/workqueue.c:

  INIT_LIST_HEAD(&wq->list);   // ...    case CPU_UP_CANCELED:             list_for_each_entry(wq, &workqueues, list) {                     if (!per_cpu_ptr(wq->cpu_wq, hotcpu)->thread)