Commit eeae7b53 authored by Greg Ames's avatar Greg Ames
Browse files

fix child process aborts with 

  assertion "!((queue)->nelts == (queue)->bounds)" failed
due to worker queue overflows. The listener/event thread
needs to block when all worker threads are busy.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@109631 13f79535-47bb-0310-9956-ffa450edef68
parent 40c37f24

server/mpm/experimental/event/event.c

+49 −3
Original line number Diff line number Diff line
@@ -748,6 +748,41 @@ static apr_status_t push2worker(const apr_pollfd_t * pfd, 
    return APR_SUCCESS;

}



/* get_worker:

 *     reserve a worker thread, block if all are currently busy.

 *     this prevents the worker queue from overflowing and lets

 *     other processes accept new connections in the mean time.

 */ 



static int get_worker(int *have_idle_worker_p)

{

    apr_status_t rc;



    if (!*have_idle_worker_p) {

        rc = ap_queue_info_wait_for_idler(worker_queue_info);



        if (rc == APR_SUCCESS) {

            *have_idle_worker_p = 1;

            return 1;

        }

        else {

            if (!APR_STATUS_IS_EOF(rc)) {

                ap_log_error(APLOG_MARK, APLOG_ERR, rc, ap_server_conf,

                             "ap_queue_info_wait_for_idler failed.  "  

                             "Attempting to shutdown process gracefully");

                signal_threads(ST_GRACEFUL);

            }

            return 0;

        }

    }

    else {

        /* already reserved a worker thread - must have hit a

         * transient error on a previous pass

         */  

        return 1; 

    }

}        



static void *listener_thread(apr_thread_t * thd, void *dummy)

{

    apr_status_t rc;
@@ -863,7 +898,7 @@ static void *listener_thread(apr_thread_t * thd, void *dummy) 
        if (listener_may_exit)

            break;



        while (num) {

        while (num && get_worker(&have_idle_worker)) {

            pt = (listener_poll_type *) out_pfd->client_data;

            if (pt->type == PT_CSD) {

                /* one of the sockets is readable */
@@ -889,6 +924,9 @@ static void *listener_thread(apr_thread_t * thd, void *dummy) 
                    ap_log_error(APLOG_MARK, APLOG_CRIT, rc,

                                 ap_server_conf, "push2worker failed");

                }

                else {

                    have_idle_worker = 0;

                }

            }

            else {

                /* A Listener Socket is ready for an accept() */
@@ -970,7 +1008,9 @@ static void *listener_thread(apr_thread_t * thd, void *dummy) 
        cs = APR_RING_FIRST(&timeout_head);

        timeout_time = time_now + TIMEOUT_FUDGE_FACTOR;

        while (!APR_RING_EMPTY(&timeout_head, conn_state_t, timeout_list)

               && cs->expiration_time < timeout_time) {

               && cs->expiration_time < timeout_time

               && get_worker(&have_idle_worker)) {



            cs->state = CONN_STATE_LINGER;



            APR_RING_REMOVE(cs, timeout_list);
@@ -979,7 +1019,13 @@ static void *listener_thread(apr_thread_t * thd, void *dummy) 


            if (rc != APR_SUCCESS) {

                return NULL;

                /* XXX return NULL looks wrong - not an init failure

                 * that bypasses all the cleanup outside the main loop

                 * break seems more like it

                 * need to evaluate seriousness of push2worker failures

                 */

            }

            have_idle_worker = 0;

            cs = APR_RING_FIRST(&timeout_head);

        }

        apr_thread_mutex_unlock(timeout_mutex);
@@ -1150,7 +1196,7 @@ static void *APR_THREAD_FUNC start_threads(apr_thread_t * thd, void *dummy) 
    /* We must create the fd queues before we start up the listener

     * and worker threads. */

    worker_queue = apr_pcalloc(pchild, sizeof(*worker_queue));

    rv = ap_queue_init(worker_queue, ap_threads_per_child * 2, pchild);

    rv = ap_queue_init(worker_queue, ap_threads_per_child, pchild);

    if (rv != APR_SUCCESS) {

        ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,

                     "ap_queue_init() failed");