Merge pull request #2654 from methane/graceful-stop

`gracefully_kill()` uses pipe to stop worker loop

core/loop.c

@@ -127,6 +127,7 @@ void *simple_loop_run(void *arg1) {
 	int main_queue = event_queue_init();
 
 	uwsgi_add_sockets_to_queue(main_queue, core_id);
+	event_queue_add_fd_read(main_queue, uwsgi.loop_stop_pipe[0]);
 
 	if (uwsgi.signal_socket > -1) {
 		event_queue_add_fd_read(main_queue, uwsgi.signal_socket);

core/uwsgi.c

@@ -1255,16 +1255,17 @@ void gracefully_kill(int signum) {
 
 	uwsgi_log("Gracefully killing worker %d (pid: %d)...\n", uwsgi.mywid, uwsgi.mypid);
 	uwsgi.workers[uwsgi.mywid].manage_next_request = 0;
+
 	if (uwsgi.threads > 1) {
-		struct wsgi_request *wsgi_req = current_wsgi_req();
-		wait_for_threads();
-		if (!uwsgi.workers[uwsgi.mywid].cores[wsgi_req->async_id].in_request) {
-			if (uwsgi.workers[uwsgi.mywid].shutdown_sockets)
-				uwsgi_shutdown_all_sockets();
-			exit(UWSGI_RELOAD_CODE);
+		// Stop event_queue_wait() in other threads.
+		// We use loop_stop_pipe only in threaded workers to avoid
+		// unintensional behavior changes in single threaded workers.
+		int fd;
+		if ((fd = uwsgi.loop_stop_pipe[1]) > 0) {
+			close(fd);
+			uwsgi.loop_stop_pipe[1] = 0;
 		}
 		return;
-		// never here
 	}
 
 	// still not found a way to gracefully reload in async mode
@@ -1296,6 +1297,17 @@ static void simple_goodbye_cruel_world(const char *reason) {
 		// Avoid showing same message from all threads.
 		uwsgi_log("...The work of process %d is done (%s). Seeya!\n", getpid(), (reason != NULL ? reason : "no reason given"));
 	}
+
+	if (uwsgi.threads > 1) {
+		// Stop event_queue_wait() in other threads.
+		// We use loop_stop_pipe only in threaded workers to avoid
+		// unintensional behavior changes in single threaded workers.
+		int fd;
+		if ((fd = uwsgi.loop_stop_pipe[1]) > 0) {
+			close(fd);
+			uwsgi.loop_stop_pipe[1] = 0;
+		}
+	}
 }
 
 void goodbye_cruel_world(const char *reason_fmt, ...) {
@@ -3641,6 +3653,10 @@ void uwsgi_ignition() {
 			exit(1);
 		}
 	}
+	if (pipe(&uwsgi.loop_stop_pipe[0])) {
+		uwsgi_error("pipe()")
+		exit(1);
+	}
 
 	// mark the worker as "accepting" (this is a mark used by chain reloading)
 	uwsgi.workers[uwsgi.mywid].accepting = 1;

uwsgi.h

@@ -2953,6 +2953,8 @@ struct uwsgi_server {
 	struct uwsgi_buffer *websockets_continuation_buffer;
 
 	uint64_t max_worker_lifetime_delta;
+	// This pipe is used to stop event_queue_wait() in threaded workers.
+	int loop_stop_pipe[2];
 };
 
 struct uwsgi_rpc {