static int kthread(void *_create)
{
struct kthread_create_info *create = _create;
int (*threadfn)(void *data);
void *data;
int ret = -EINTR;
/* Copy data: it's on kthread's stack */
threadfn = create->threadfn;
data = create->data;
/* OK, tell user we're spawned, wait for stop or wakeup */
__set_current_state(TASK_UNINTERRUPTIBLE);
complete(&create->started);
schedule();
if (!kthread_should_stop())
ret = threadfn(data);
/* It might have exited on its own, w/o kthread_stop. Check. */
if (kthread_should_stop()) {
kthread_stop_info.err = ret;
complete(&kthread_stop_info.done);
}
return 0;
这个就是kthead的故事。
看到了上面的这些，其实kernel确实也不容易，里面我忽略了很多东西。在其他时间，内核的同步机制，我再整一整。
内核的同步机制：原子操作，锁，信号亮，完成变量。