Method Start

src/brpc/event_dispatcher_kqueue.cpp:58–95

}

int EventDispatcher::Start(const bthread_attr_t* thread_attr) {
    if (_event_dispatcher_fd < 0) {
        LOG(FATAL) << "kqueue was not created";
        return -1;
    }
    
    if (_tid != 0) {
        LOG(FATAL) << "Already started this dispatcher(" << this 
                   << ") in bthread=" << _tid;
        return -1;
    }

    // Set _thread_attr before creating kqueue thread to make sure
    // everyting seems sane to the thread.
    if (thread_attr) {
        _thread_attr = *thread_attr;
    }

    //_thread_attr is used in StartInputEvent(), assign flag NEVER_QUIT to it will cause new bthread
    // that created by kevent() never to quit.
    // Only event dispatcher thread has flag BTHREAD_GLOBAL_PRIORITY.
    bthread_attr_t kqueue_thread_attr =
        _thread_attr | BTHREAD_NEVER_QUIT | BTHREAD_GLOBAL_PRIORITY;
    bthread_attr_set_name(&kqueue_thread_attr, "EventDispatcher::RunThis");

    // Polling thread uses the same attr for consumer threads (NORMAL right
    // now). Previously, we used small stack (32KB) which may be overflowed
    // when the older comlog (e.g. 3.1.85) calls com_openlog_r(). Since this
    // is also a potential issue for consumer threads, using the same attr
    // should be a reasonable solution.
    int rc = bthread_start_background(
        &_tid, &kqueue_thread_attr, RunThis, this);
    if (rc) {
        LOG(FATAL) << "Fail to create kqueue thread: " << berror(rc);
        return -1;
    }
    return 0;
}

bool EventDispatcher::Running() const {
    return !_stop  && _event_dispatcher_fd >= 0 && _tid != 0;