Merge remote-tracking branch 'arma/bug19969_028_squashed' into maint-0.2.8

changes/bug19969

@@ -0,0 +1,10 @@
+  o Major bugfixes (client performance);
+    - Clients now respond to new application stream requests when
+      they arrive, rather than waiting up to one second before starting
+      to handle them. Fixes part of bug 19969; bugfix on 0.2.8.1-alpha.
+
+  o Major bugfixes (clients on flaky network connections);
+    - When Tor leaves standby because of a new application request, open
+      circuits as needed to serve that request. Previously, we would
+      potentially wait a very long time. Fixes part of bug 19969; bugfix
+      on 0.2.8.1-alpha.

src/or/connection_edge.c

@@ -892,6 +892,15 @@ connection_ap_mark_as_pending_circuit_(entry_connection_t *entry_conn,
 
   untried_pending_connections = 1;
   smartlist_add(pending_entry_connections, entry_conn);
+
+  /* Work-around for bug 19969: we handle pending_entry_connections at
+   * the end of run_main_loop_once(), but in many cases that function will
+   * take a very long time, if ever, to finish its call to event_base_loop().
+   *
+   * So the fix is to tell it right now that it ought to finish its loop at
+   * its next available opportunity.
+   */
+  tell_event_loop_to_finish();
 }
 
 /** Mark <b>entry_conn</b> as no longer waiting for a circuit. */

src/or/main.c

@@ -726,6 +726,19 @@ connection_should_read_from_linked_conn(connection_t *conn)
   return 0;
 }
 
+/** If we called event_base_loop() and told it to never stop until it
+ * runs out of events, now we've changed our mind: tell it we want it to
+ * finish. */
+void
+tell_event_loop_to_finish(void)
+{
+  if (!called_loop_once) {
+    struct timeval tv = { 0, 0 };
+    tor_event_base_loopexit(tor_libevent_get_base(), &tv);
+    called_loop_once = 1; /* hack to avoid adding more exit events */
+  }
+}
+
 /** Helper: Tell the main loop to begin reading bytes into <b>conn</b> from
  * its linked connection, if it is not doing so already.  Called by
  * connection_start_reading and connection_start_writing as appropriate. */
@@ -738,14 +751,10 @@ connection_start_reading_from_linked_conn(connection_t *conn)
   if (!conn->active_on_link) {
     conn->active_on_link = 1;
     smartlist_add(active_linked_connection_lst, conn);
-    if (!called_loop_once) {
-      /* This is the first event on the list; we won't be in LOOP_ONCE mode,
-       * so we need to make sure that the event_base_loop() actually exits at
-       * the end of its run through the current connections and lets us
+    /* make sure that the event_base_loop() function exits at
+     * the end of its run through the current connections, so we can
      * activate read events for linked connections. */
-      struct timeval tv = { 0, 0 };
-      tor_event_base_loopexit(tor_libevent_get_base(), &tv);
-    }
+    tell_event_loop_to_finish();
   } else {
     tor_assert(smartlist_contains(active_linked_connection_lst, conn));
   }
@@ -1516,6 +1525,12 @@ run_scheduled_events(time_t now)
     circuit_expire_old_circs_as_needed(now);
   }
 
+  if (!net_is_disabled()) {
+    /* This is usually redundant with circuit_build_needed_circs() above,
+     * but it is very fast when there is no work to do. */
+    connection_ap_attach_pending(0);
+  }
+
   /* 5. We do housekeeping for each connection... */
   connection_or_set_bad_connections(NULL, 0);
   int i;

src/or/main.h

@@ -45,6 +45,8 @@ int connection_is_writing(connection_t *conn);
 MOCK_DECL(void,connection_stop_writing,(connection_t *conn));
 MOCK_DECL(void,connection_start_writing,(connection_t *conn));
 
+void tell_event_loop_to_finish(void);
+
 void connection_stop_reading_from_linked_conn(connection_t *conn);
 
 void directory_all_unreachable(time_t now);