Commit 229217ee authored by Greg Ames's avatar Greg Ames
Browse files

Fix a problem where the threaded MPM stalls after restarts or segfaults. 

Also prevent multiple active processes from using the same scoreboard slot.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@89761 13f79535-47bb-0310-9956-ffa450edef68
parent c78047ab

CHANGES

+4 −0
Original line number Diff line number Diff line
@@ -6,6 +6,10 @@ Changes with Apache 2.0.23 


Changes with Apache 2.0.22

  

  *) Fix a problem where the threaded MPM stalls after restarts or

     segfaults.  Also prevent multiple active processes from using

     the same scoreboard slot.  [Greg Ames]



  *) Apache/Win32 now fills in the service description with Apache's

     server version string, including loaded and advertised modules.

     [William Rowe]

include/scoreboard.h

+3 −0
Original line number Diff line number Diff line
@@ -178,6 +178,9 @@ struct process_score{ 
    pid_t pid;

    ap_generation_t generation;	/* generation of this child */

    ap_scoreboard_e sb_type;

    int quiescing;          /* the process whose pid is stored above is

                             * going down gracefully

                             */

};



typedef struct {

server/mpm/threaded/threaded.c

+23 −3
Original line number Diff line number Diff line
@@ -648,8 +648,15 @@ static void * worker_thread(apr_thread_t *thd, void * dummy) 
    apr_pool_destroy(tpool);

    ap_update_child_status(process_slot, thread_slot, (dying) ? SERVER_DEAD : SERVER_GRACEFUL,

        (request_rec *) NULL);

    dying = 1;

    apr_lock_acquire(worker_thread_count_mutex);

    if (!dying) {

        /* this is the first thread to exit */

        if (ap_my_pid == ap_scoreboard_image->parent[process_slot].pid) {

            /* tell the parent that it may use this scoreboard slot */

            ap_scoreboard_image->parent[process_slot].quiescing = 1;

        }   

        dying = 1;

    }

    worker_thread_count--;

    if (worker_thread_count == 0) {

        /* All the threads have exited, now finish the shutdown process
@@ -900,6 +907,7 @@ static int make_child(server_rec *s, int slot) 
        clean_child_exit(0);

    }

    /* else */

    ap_scoreboard_image->parent[slot].quiescing = 0;

    ap_scoreboard_image->parent[slot].pid = pid;

    return 0;

}
@@ -961,6 +969,7 @@ static void perform_idle_server_maintenance(void) 
    int i, j;

    int idle_thread_count;

    worker_score *ws;

    process_score *ps;

    int free_length;

    int free_slots[MAX_SPAWN_RATE];

    int last_non_dead;
@@ -985,6 +994,7 @@ static void perform_idle_server_maintenance(void) 


	if (i >= ap_max_daemons_limit && free_length == idle_spawn_rate)

	    break;

        ps = &ap_scoreboard_image->parent[i];

	for (j = 0; j < ap_threads_per_child; j++) {

            ws = &ap_scoreboard_image->servers[i][j];

	    status = ws->status;
@@ -998,11 +1008,19 @@ static void perform_idle_server_maintenance(void) 
	     * So we hopefully won't need to fork more if we count it.

	     * This depends on the ordering of SERVER_READY and SERVER_STARTING.

	     */

	    if (status <= SERVER_READY && status != SERVER_DEAD) {

	    if (status <= SERVER_READY && status != SERVER_DEAD &&

                    ps->generation == ap_my_generation && 

                 /* XXX the following shouldn't be necessary if we clean up 

                  *     properly after seg faults, but we're not yet    GLA 

                  */     

                    ps->pid != 0) {

	        ++idle_thread_count;

	    }

	}

	if (any_dead_threads && free_length < idle_spawn_rate) {

        /* XXX any_dead_threads may not be needed any more GLA */

        if (any_dead_threads && free_length < idle_spawn_rate 

                && (!ps->pid               /* no process in the slot */

                    || ps->quiescing)) {   /* or at least one is going away */

	    free_slots[free_length] = i;

	    ++free_length;

	}
@@ -1083,6 +1101,8 @@ static void server_main_loop(int remaining_children_to_start) 
                for (i = 0; i < ap_threads_per_child; i++)

                    ap_update_child_status(child_slot, i, SERVER_DEAD, (request_rec *) NULL);

                

                ap_scoreboard_image->parent[child_slot].pid = 0;

                ap_scoreboard_image->parent[child_slot].quiescing = 0;

		if (remaining_children_to_start

		    && child_slot < ap_daemons_limit) {

		    /* we're still doing a 1-for-1 replacement of dead