把空闲 keep-alive 连接交给监听线程

1293    if (cs->pub.state == CONN_STATE_KEEPALIVE) {1294        ap_update_child_status(cs->sbh, SERVER_BUSY_KEEPALIVE, NULL);12951296        /* It greatly simplifies the logic to use a single timeout value per q1297         * because the new element can just be added to the end of the list and1298         * it will stay sorted in expiration time sequence.  If brand new1299         * sockets are sent to the event thread for a readability check, this1300         * will be a slight behavior change - they use the non-keepalive1301         * timeout today.  With a normal client, the socket will be readable in1302         * a few milliseconds anyway.1303         */1304        cs->queue_timestamp = apr_time_now();1305        notify_suspend(cs);13061307        /* Add work to pollset. */1308        cs->pub.sense = CONN_SENSE_DEFAULT;1309        update_reqevents_from_sense(cs, CONN_SENSE_WANT_READ);1310        apr_thread_mutex_lock(timeout_mutex);1311        TO_QUEUE_APPEND(cs->sc->ka_q, cs);1312        rv = apr_pollset_add(event_pollset, &cs->pfd);

299static void TO_QUEUE_APPEND(struct timeout_queue *q, event_conn_state_t *el)300{301    apr_time_t elem_expiry;302    apr_time_t next_expiry;303304    APR_RING_INSERT_TAIL(&q->head, el, event_conn_state_t, timeout_list);305    ++*q->total;306    ++q->count;307308    /* Cheaply update the global queues_next_expiry with the one of the309     * first entry of this queue (oldest) if it expires before.310     */311    el = APR_RING_FIRST(&q->head);312    elem_expiry = el->queue_timestamp + q->timeout;313    next_expiry = queues_next_expiry;314    if (!next_expiry || next_expiry > elem_expiry + TIMEOUT_FUDGE_FACTOR) {315        queues_next_expiry = elem_expiry;316        /* Unblock the poll()ing listener for it to update its timeout. */317        if (listener_is_wakeable) {318            apr_pollset_wakeup(event_pollset);319        }320    }

2149                case CONN_STATE_KEEPALIVE:2150                    cs->pub.state = CONN_STATE_PROCESSING;2151                    remove_from_q = cs->sc->ka_q;2152                    break;21532154                case CONN_STATE_LINGER_NORMAL:2155                    remove_from_q = linger_q;2156                    break;21572158                case CONN_STATE_LINGER_SHORT:2159                    remove_from_q = short_linger_q;

2190                    /* If we don't get a worker immediately (nonblocking), we2191                     * close the connection; the client can re-connect to a2192                     * different process for keepalive, and for lingering close2193                     * the connection will be shutdown so the choice is to favor2194                     * incoming/alive connections.2195                     */2196                    get_worker(&have_idle_worker, blocking,2197                               &workers_were_busy);2198                    if (!have_idle_worker) {2199                        shutdown_connection(cs);2200                    }2201                    else if (push2worker(cs, NULL, NULL) == APR_SUCCESS) {2202                        have_idle_worker = 0;2203                    }

1875             * - no expiry was given (zero means all), or1876             * - it expired (according to the queue timeout), or1877             * - the system clock skewed in the past: no entry should be1878             *   registered above the given expiry (~now) + the queue1879             *   timeout, we won't keep any here (eg. for centuries).1880             *1881             * Otherwise stop, no following entry will match thanks to the1882             * single timeout per queue (entries are added to the end!).1883             * This allows maintenance in O(1).1884             */1885            if (expiry && cs->queue_timestamp + qp->timeout > expiry1886                       && cs->queue_timestamp < expiry + qp->timeout) {1887                /* Since this is the next expiring entry of this queue, update1888                 * the global queues_next_expiry if it's later than this one.1889                 */1890                apr_time_t elem_expiry = cs->queue_timestamp + qp->timeout;1891                apr_time_t next_expiry = queues_next_expiry;1892                if (!next_expiry1893                        || next_expiry > elem_expiry + TIMEOUT_FUDGE_FACTOR) {1894                    queues_next_expiry = elem_expiry;1895                }1896                break;

1912        APR_RING_UNSPLICE(first, last, timeout_list);1913        APR_RING_SPLICE_TAIL(&trash.timeout_list, first, last, event_conn_state_t,1914                             timeout_list);1915        AP_DEBUG_ASSERT(*q->total >= count && qp->count >= count);1916        *q->total -= count;1917        qp->count -= count;1918        total += count;1919    }1920    if (!total)1921        return;19221923    apr_thread_mutex_unlock(timeout_mutex);1924    first = APR_RING_FIRST(&trash.timeout_list);1925    do {1926        cs = APR_RING_NEXT(first, timeout_list);1927        TO_QUEUE_ELEM_INIT(first);1928        func(first);1929        first = cs;1930    } while (--total);