//任务添加到对应的线程池任务队列中
ngx_int_t //ngx_thread_pool_cycle和ngx_thread_task_post配合阅读
ngx_thread_task_post(ngx_thread_pool_t *tp, ngx_thread_task_t *task)
{
if (task->event.active) {
ngx_log_error(NGX_LOG_ALERT, tp->log, 0,
"task #%ui already active", task->id);
return NGX_ERROR;
}
if (ngx_thread_mutex_lock(&tp->mtx, tp->log) != NGX_OK) {
return NGX_ERROR;
}
if (tp->waiting >= tp->max_queue) {
(void) ngx_thread_mutex_unlock(&tp->mtx, tp->log);
ngx_log_error(NGX_LOG_ERR, tp->log, 0,
"thread pool \"%V\" queue overflow: %i tasks waiting",
&tp->name, tp->waiting);
return NGX_ERROR;
}
task->event.active = 1;
task->id = ngx_thread_pool_task_id++;
task->next = NULL;
ngx_log_debugall(tp->log, 0, "ngx add task to thread, task id:%ui", task->id);
if (ngx_thread_cond_signal(&tp->cond, tp->log) != NGX_OK) {
(void) ngx_thread_mutex_unlock(&tp->mtx, tp->log);
return NGX_ERROR;
}
//添加到任务队列
*tp->queue.last = task;
tp->queue.last = &task->next;
tp->waiting++;
(void) ngx_thread_mutex_unlock(&tp->mtx, tp->log);
ngx_log_debug2(NGX_LOG_DEBUG_CORE, tp->log, 0,
"task #%ui added to thread pool name: \"%V\" complete",
task->id, &tp->name);
return NGX_OK;
}
static void *
ngx_thread_pool_cycle(void *data)
{
ngx_thread_pool_t *tp = data;
int err;
sigset_t set;
ngx_thread_task_t *task;
#if 0
ngx_time_update();
#endif
ngx_log_debug1(NGX_LOG_DEBUG_CORE, tp->log, 0,
"thread in pool \"%V\" started", &tp->name);
sigfillset(&set);
sigdelset(&set, SIGILL);
sigdelset(&set, SIGFPE);
sigdelset(&set, SIGSEGV);
sigdelset(&set, SIGBUS);
err = pthread_sigmask(SIG_BLOCK, &set, NULL);
if (err)
{
ngx_log_error(NGX_LOG_ALERT, tp->log, err, "pthread_sigmask() failed");
return NULL;
}
for (;;)
{
if (ngx_thread_mutex_lock(&tp->mtx, tp->log) != NGX_OK)
{
return NULL;
}
/* the number may become negative */
tp->waiting--;
while (tp->queue.first == NULL)
{
if (ngx_thread_cond_wait(&tp->cond, &tp->mtx, tp->log)
!= NGX_OK)
{
(void) ngx_thread_mutex_unlock(&tp->mtx, tp->log);
return NULL;
}
}
task = tp->queue.first;
tp->queue.first = task->next;
if (tp->queue.first == NULL)
{
tp->queue.last = &tp->queue.first;
}
if (ngx_thread_mutex_unlock(&tp->mtx, tp->log) != NGX_OK)
{
return NULL;
}
#if 0
ngx_time_update();
#endif
ngx_log_debug2(NGX_LOG_DEBUG_CORE, tp->log, 0,
"run task #%ui in thread pool \"%V\"",
task->id, &tp->name);
task->handler(task->ctx, tp->log);
ngx_log_debug2(NGX_LOG_DEBUG_CORE, tp->log, 0,
"complete task #%ui in thread pool \"%V\"",
task->id, &tp->name);
task->next = NULL;
ngx_spinlock(&ngx_thread_pool_done_lock, 1, 2048);
*ngx_thread_pool_done.last = task;
ngx_thread_pool_done.last = &task->next;
ngx_unlock(&ngx_thread_pool_done_lock);
(void) ngx_notify(ngx_thread_pool_handler);
}
}
//ngx_thread_pool_cycle和ngx_thread_task_post配合阅读
static void *
ngx_thread_pool_cycle(void *data)
{
ngx_thread_pool_t *tp = data; //一个该结构对应一个threads_pool配置
int err;
sigset_t set;
ngx_thread_task_t *task;
#if 0
ngx_time_update();
#endif
ngx_log_debug1(NGX_LOG_DEBUG_CORE, tp->log, 0,
"thread in pool \"%V\" started", &tp->name);
sigfillset(&set);
sigdelset(&set, SIGILL);
sigdelset(&set, SIGFPE);
sigdelset(&set, SIGSEGV);
sigdelset(&set, SIGBUS);
err = pthread_sigmask(SIG_BLOCK, &set, NULL); //
if (err) {
ngx_log_error(NGX_LOG_ALERT, tp->log, err, "pthread_sigmask() failed");
return NULL;
}
/*
一般主线程通过ngx_thread_task_post添加任务，线程队列中的线程执行任务，主线程号和进程号一样，线程队列中的线程和进程号不一样，例如
2016/01/07 12:38:01[ ngx_thread_task_post, 280][yangya [debug] 20090#20090: ngx add task to thread, task id:183
20090#20090前面是进程号，后面是主线程号，他们相同
*/
for ( ;; ) {//一次任务执行完后又会走到这里，循环
if (ngx_thread_mutex_lock(&tp->mtx, tp->log) != NGX_OK) {
return NULL;
}
/* the number may become negative */
tp->waiting--;
//如果队列中有任务，则直接执行任务，不会在while中等待conf signal
while (tp->queue.first == NULL) { //此时任务队列为空，在条件变量上等待 配合ngx_thread_task_post阅读
//在添加任务的时候唤醒ngx_thread_task_post -> ngx_thread_cond_signal
if (ngx_thread_cond_wait(&tp->cond, &tp->mtx, tp->log) //等待ngx_thread_cond_signal后才会返回
!= NGX_OK)
{
(void) ngx_thread_mutex_unlock(&tp->mtx, tp->log);
return NULL;
}
}
//取出队首任务，然后执行
task = tp->queue.first;
tp->queue.first = task->next;
if (tp->queue.first == NULL) {
tp->queue.last = &tp->queue.first;
}
//这一段加锁是因为线程池是共享资源，多个线程都从队列中取线程，并且主线程会添加任务到队列中
if (ngx_thread_mutex_unlock(&tp->mtx, tp->log) != NGX_OK) {
return NULL;
}
#if 0
ngx_time_update();
#endif
ngx_log_debug2(NGX_LOG_DEBUG_CORE, tp->log, 0,
"run task #%ui in thread pool name:\"%V\"",
task->id, &tp->name);
task->handler(task->ctx, tp->log); //每个任务有各自的ctx,因此这里不需要加锁
ngx_log_debug2(NGX_LOG_DEBUG_CORE, tp->log, 0,
"complete task #%ui in thread pool name: \"%V\"",
task->id, &tp->name);
task->next = NULL;
ngx_spinlock(&ngx_thread_pool_done_lock, 1, 2048);
//task添加到队列尾部，同时可以保证多次添加的时候，让新task和以前的task形成一个还，first执行第一个task，last指向最后一个task
*ngx_thread_pool_done.last = task;
ngx_thread_pool_done.last = &task->next;
ngx_unlock(&ngx_thread_pool_done_lock);
//ngx_notify通告主线程，该任务处理完毕，ngx_thread_pool_handler由主线程执行，也就是进程cycle{}通过epoll_wait返回执行，而不是由线程池中的线程执行
(void) ngx_notify(ngx_thread_pool_handler);
}
}
