merge bug26013 into stable

1 files changed, 44 insertions, 32 deletions

diff --git a/src/rabbit_reader.erl b/src/rabbit_reader.erl
index 1ae9bacf..f9fd4d4e 100644
--- a/src/rabbit_reader.erl
+++ b/src/rabbit_reader.erl
@@ -44,8 +44,7 @@
                      client_properties, capabilities,
                      auth_mechanism, auth_state}).
 
--record(throttle, {alarmed_by, last_blocked_by, last_blocked_at,
-                   blocked_sent}).
+-record(throttle, {alarmed_by, last_blocked_by, last_blocked_at}).
 
 -define(STATISTICS_KEYS, [pid, recv_oct, recv_cnt, send_oct, send_cnt,
                           send_pend, state, last_blocked_by, last_blocked_age,
@@ -243,8 +242,7 @@ start_connection(Parent, HelperSup, Deb, Sock, SockTransform) ->
                 throttle            = #throttle{
                                          alarmed_by      = [],
                                          last_blocked_by = none,
-                                         last_blocked_at = never,
-                                         blocked_sent    = false}},
+                                         last_blocked_at = never}},
     try
         run({?MODULE, recvloop,
              [Deb, switch_callback(rabbit_event:init_stats_timer(
@@ -323,14 +321,19 @@ stop(Reason, State) -> maybe_emit_stats(State),
                        throw({inet_error, Reason}).
 
 handle_other({conserve_resources, Source, Conserve},
-             State = #v1{throttle = Throttle =
-                             #throttle{alarmed_by = CR}}) ->
+             State = #v1{throttle = Throttle = #throttle{alarmed_by = CR}}) ->
     CR1 = case Conserve of
               true  -> lists:usort([Source | CR]);
               false -> CR -- [Source]
           end,
-    Throttle1 = Throttle#throttle{alarmed_by = CR1},
-    control_throttle(State#v1{throttle = Throttle1});
+    State1 = control_throttle(
+               State#v1{throttle = Throttle#throttle{alarmed_by = CR1}}),
+    case {blocked_by_alarm(State), blocked_by_alarm(State1)} of
+        {false, true} -> ok = send_blocked(State1);
+        {true, false} -> ok = send_unblocked(State1);
+        {_,        _} -> ok
+    end,
+    State1;
 handle_other({channel_closing, ChPid}, State) ->
     ok = rabbit_channel:ready_for_close(ChPid),
     channel_cleanup(ChPid),
@@ -422,10 +425,7 @@ control_throttle(State = #v1{connection_state = CS, throttle = Throttle}) ->
         {blocking, false} -> State#v1{connection_state = running};
         {blocked,  false} -> ok = rabbit_heartbeat:resume_monitor(
                                     State#v1.heartbeater),
-                             maybe_send_unblocked(State),
-                             State#v1{connection_state = running,
-                                      throttle = Throttle#throttle{
-                                                   blocked_sent = false}};
+                             State#v1{connection_state = running};
         {blocked,   true} -> State#v1{throttle = update_last_blocked_by(
                                                    Throttle)};
         {_,            _} -> State
@@ -434,37 +434,49 @@ control_throttle(State = #v1{connection_state = CS, throttle = Throttle}) ->
 maybe_block(State = #v1{connection_state = blocking,
                         throttle         = Throttle}) ->
     ok = rabbit_heartbeat:pause_monitor(State#v1.heartbeater),
-    Sent = maybe_send_blocked(State),
-    State#v1{connection_state = blocked,
-             throttle = update_last_blocked_by(
-                          Throttle#throttle{last_blocked_at = erlang:now(),
-                                            blocked_sent    = Sent})};
+    State1 = State#v1{connection_state = blocked,
+                      throttle = update_last_blocked_by(
+                                   Throttle#throttle{
+                                     last_blocked_at = erlang:now()})},
+    case {blocked_by_alarm(State), blocked_by_alarm(State1)} of
+        {false, true} -> ok = send_blocked(State1);
+        {_,        _} -> ok
+    end,
+    State1;
 maybe_block(State) ->
     State.
 
-maybe_send_blocked(#v1{throttle = #throttle{alarmed_by = []}}) ->
-    false;
-maybe_send_blocked(#v1{throttle   = #throttle{alarmed_by = CR},
-                       connection = #connection{
-                                       protocol     = Protocol,
-                                       capabilities = Capabilities},
-                       sock       = Sock}) ->
+
+blocked_by_alarm(#v1{connection_state = blocked,
+                     throttle         = #throttle{alarmed_by = CR}})
+  when CR =/= [] ->
+    true;
+blocked_by_alarm(#v1{}) ->
+    false.
+
+send_blocked(#v1{throttle   = #throttle{alarmed_by = CR},
+                 connection = #connection{protocol     = Protocol,
+                                          capabilities = Capabilities},
+                 sock       = Sock}) ->
     case rabbit_misc:table_lookup(Capabilities, <<"connection.blocked">>) of
         {bool, true} ->
             RStr = string:join([atom_to_list(A) || A <- CR], " & "),
             Reason = list_to_binary(rabbit_misc:format("low on ~s", [RStr])),
             ok = send_on_channel0(Sock, #'connection.blocked'{reason = Reason},
-                                  Protocol),
-            true;
+                                  Protocol);
         _ ->
-            false
+            ok
     end.
 
-maybe_send_unblocked(#v1{throttle = #throttle{blocked_sent = false}}) ->
-    ok;
-maybe_send_unblocked(#v1{connection = #connection{protocol = Protocol},
-                         sock       = Sock}) ->
-    ok = send_on_channel0(Sock, #'connection.unblocked'{}, Protocol).
+send_unblocked(#v1{connection = #connection{protocol     = Protocol,
+                                            capabilities = Capabilities},
+                   sock       = Sock}) ->
+    case rabbit_misc:table_lookup(Capabilities, <<"connection.blocked">>) of
+        {bool, true} ->
+            ok = send_on_channel0(Sock, #'connection.unblocked'{}, Protocol);
+        _ ->
+            ok
+    end.
 
 update_last_blocked_by(Throttle = #throttle{alarmed_by = []}) ->
     Throttle#throttle{last_blocked_by = flow};