一、协程如何被调度？
调度器的实现，有两种方案，一种是生产者消费者模式，另一种多状态运行。
1.1 生产者消费者模式
逻辑代码如下：
1 while (1) {
2
3 //遍历睡眠集合，将满足条件的加入到ready
4 nty_coroutine *expired = NULL;
5 while ((expired = sleep_tree_expired(sched)) != ) {
6 TAILQ_ADD(&sched->ready, expired);
7 }
8
9 //遍历等待集合，将满足添加的加入到ready
10 nty_coroutine *wait = NULL;
11 int nready = epoll_wait(sched->epfd, events, EVENT_MAX, 1);
12 for (i = 0;i < nready;i ++) {
13 wait = wait_tree_search(events[i].data.fd);
14 TAILQ_ADD(&sched->ready, wait);
15 }
16
17 // 使用resume回复ready的协程运行权
18 while (!TAILQ_EMPTY(&sched->ready)) {
19 nty_coroutine *ready = TAILQ_POP(sched->ready);
20 resume(ready);
21 }
22 }
1.2 多状态运行
实现逻辑代码如下：
1 while (1) {
2
3 //遍历睡眠集合，使用resume恢复expired的协程运行权
4 nty_coroutine *expired = NULL;
5 while ((expired = sleep_tree_expired(sched)) != ) {
6 resume(expired);
7 }
8
9 //遍历等待集合，使用resume恢复wait的协程运行权
10 nty_coroutine *wait = NULL;
11 int nready = epoll_wait(sched->epfd, events, EVENT_MAX, 1);
12 for (i = 0;i < nready;i ++) {
13 wait = wait_tree_search(events[i].data.fd);
14 resume(wait);
15 }
16
17 // 使用resume恢复ready的协程运行权
18 while (!TAILQ_EMPTY(sched->ready)) {
19 nty_coroutine *ready = TAILQ_POP(sched->ready);
20 resume(ready);
21 }
22 }
转载：
https://blog.csdn.net/Yttsam/article/details/107388747