Author: Curt Sampson <cjs@cynic.net>

--- pkg.orig/src/mod_fastcgi.c	(revision 4423)
+++ pkg/src/mod_fastcgi.c	(working copy)
@@ -256,6 +256,13 @@
				       applications prefer SIGUSR1 while the
				       rest of the world would use SIGTERM
				       *sigh* */
+
+	/*
+         * If this limit is >= 0, and the queue of requests waiting for
+         * a FastCGI backend to become free would become larger than
+         * this, send a 503 response instead of queueing the request.
+	 */
+	signed short request_queue_limit;
 } fcgi_extension_host;
 
 /*
@@ -1193,6 +1193,7 @@
						{ "allow-x-send-file",  NULL, T_CONFIG_BOOLEAN, T_CONFIG_SCOPE_CONNECTION },      /* 15 */
						{ "strip-request-uri",  NULL, T_CONFIG_STRING, T_CONFIG_SCOPE_CONNECTION },      /* 16 */
						{ "kill-signal",        NULL, T_CONFIG_SHORT, T_CONFIG_SCOPE_CONNECTION },      /* 17 */
+						{ "request-queue-limit", NULL, T_CONFIG_SHORT, T_CONFIG_SCOPE_CONNECTION },      /* 18 */

 						{ NULL,                NULL, T_CONFIG_UNSET, T_CONFIG_SCOPE_UNSET }
 					};
@@ -1220,6 +1220,7 @@
					host->break_scriptfilename_for_php = 0;
					host->allow_xsendfile = 0; /* handle X-LIGHTTPD-send-file */
					host->kill_signal = SIGTERM;
+					host->request_queue_limit = -1;
 
 					fcv[0].destination = host->host;
 					fcv[1].destination = host->docroot;
@@ -1241,6 +1241,7 @@
 					fcv[15].destination = &(host->allow_xsendfile);
 					fcv[16].destination = host->strip_request_uri;
					fcv[17].destination = &(host->kill_signal);
+					fcv[18].destination = &(host->request_queue_limit);
 
 					if (0 != config_insert_values_internal(srv, da_host->value, fcv)) {
 						return HANDLER_ERROR;
@@ -3124,6 +3124,19 @@
		host = hctx->host;
	}
 
+	/* overload check */
+	if (host->request_queue_limit >= 0 && host->load > host->request_queue_limit) {
+		if (p->conf.debug > 0) {
+			log_error_write(srv, __FILE__, __LINE__, "sbsd",
+					"request for ", con->uri.path,
+					"rejected; current load is ", host->load);
+		}
+		fcgi_connection_close(srv, hctx);
+		con->http_status = 503;
+		con->mode = DIRECT;
+		return HANDLER_FINISHED;
+	}
+
 	/* ok, create the request */
 	switch(fcgi_write_request(srv, hctx)) {
 	case HANDLER_ERROR:
--- pkg.orig/doc/fastcgi.txt	(revision 4423)
+++ pkg/doc/fastcgi.txt	(working copy)
@@ -111,6 +111,7 @@
 	  "broken-scriptfilename" => <boolean>, # OPTIONAL
           "disable-time" => <integer>, # optional
           "allow-x-send-file" => <boolean> # optional
+	  "request-queue-limit" => <integer>, # OPTIONAL
 	),
         ( "host" => ...
         )
@@ -146,6 +147,11 @@
                 again
   :"allow-x-send-file": controls if X-LIGHTTPD-send-file headers
                 are allowed
+  :"request-queue-limit": is optional, and defaults to -1. 
+                If this limit is >= 0, and the queue of requests waiting
+                for a FastCGI process to become available to serve them
+                would become larger than this, send a 503 response
+                instead of queueing the request.
 
   If bin-path is set: