merge bug21087 into default

3 files changed, 300 insertions, 83 deletions

diff --git a/src/gen_server2.erl b/src/gen_server2.erl
index ba8becfc..36fb4fa8 100644
--- a/src/gen_server2.erl
+++ b/src/gen_server2.erl
@@ -1,4 +1,4 @@
-%% This file is a copy of gen_server.erl from the R11B-5 Erlang/OTP
+%% This file is a copy of gen_server.erl from the R13B-1 Erlang/OTP
 %% distribution, with the following modifications:
 %%
 %% 1) the module name is gen_server2
@@ -21,6 +21,42 @@
 %% higher priorities are processed before requests with lower
 %% priorities. The default priority is 0.
 %%
+%% 5) The callback module can optionally implement
+%% handle_pre_hibernate/1 and handle_post_hibernate/1. These will be
+%% called immediately prior to and post hibernation, respectively. If
+%% handle_pre_hibernate returns {hibernate, NewState} then the process
+%% will hibernate. If the module does not implement
+%% handle_pre_hibernate/1 then the default action is to hibernate.
+%%
+%% 6) init can return a 4th arg, {backoff, InitialTimeout,
+%% MinimumTimeout, DesiredHibernatePeriod} (all in
+%% milliseconds). Then, on all callbacks which can return a timeout
+%% (including init), timeout can be 'hibernate'. When this is the
+%% case, the current timeout value will be used (initially, the
+%% InitialTimeout supplied from init). After this timeout has
+%% occurred, hibernation will occur as normal. Upon awaking, a new
+%% current timeout value will be calculated.
+%% 
+%% The purpose is that the gen_server2 takes care of adjusting the
+%% current timeout value such that the process will increase the
+%% timeout value repeatedly if it is unable to sleep for the
+%% DesiredHibernatePeriod. If it is able to sleep for the
+%% DesiredHibernatePeriod it will decrease the current timeout down to
+%% the MinimumTimeout, so that the process is put to sleep sooner (and
+%% hopefully stays asleep for longer). In short, should a process
+%% using this receive a burst of messages, it should not hibernate
+%% between those messages, but as the messages become less frequent,
+%% the process will not only hibernate, it will do so sooner after
+%% each message.
+%%
+%% When using this backoff mechanism, normal timeout values (i.e. not
+%% 'hibernate') can still be used, and if they are used then the
+%% handle_info(timeout, State) will be called as normal. In this case,
+%% returning 'hibernate' from handle_info(timeout, State) will not
+%% hibernate the process immediately, as it would if backoff wasn't
+%% being used. Instead it'll wait for the current timeout as described
+%% above.
+
 %% All modifications are (C) 2009 LShift Ltd.
 
 %% ``The contents of this file are subject to the Erlang Public License,
@@ -55,6 +91,7 @@
 %%%   init(Args)  
 %%%     ==> {ok, State}
 %%%         {ok, State, Timeout}
+%%%         {ok, State, Timeout, Backoff}
 %%%         ignore
 %%%         {stop, Reason}
 %%%
@@ -86,6 +123,17 @@
 %%%
 %%%    ==> ok
 %%%
+%%%   handle_pre_hibernate(State)
+%%%
+%%%    ==> {hibernate, State}
+%%%        {stop, Reason, State}
+%%%              Reason = normal | shutdown | Term, terminate(State) is called
+%%%
+%%%   handle_post_hibernate(State)
+%%%
+%%%    ==> {noreply, State}
+%%%        {stop, Reason, State}
+%%%              Reason = normal | shutdown | Term, terminate(State) is called
 %%%
 %%% The work flow (of the server) can be described as follows:
 %%%
@@ -116,7 +164,7 @@
 	 cast/2, pcast/3, reply/2,
 	 abcast/2, abcast/3,
 	 multi_call/2, multi_call/3, multi_call/4,
-	 enter_loop/3, enter_loop/4, enter_loop/5]).
+	 enter_loop/3, enter_loop/4, enter_loop/5, wake_hib/7]).
 
 -export([behaviour_info/1]).
 
@@ -290,7 +338,7 @@ multi_call(Nodes, Name, Req, Timeout)
 
 
 %%-----------------------------------------------------------------
-%% enter_loop(Mod, Options, State, <ServerName>, <TimeOut>) ->_ 
+%% enter_loop(Mod, Options, State, <ServerName>, <TimeOut>, <Backoff>) ->_ 
 %%   
 %% Description: Makes an existing process into a gen_server. 
 %%              The calling process will enter the gen_server receive 
@@ -301,20 +349,30 @@ multi_call(Nodes, Name, Req, Timeout)
 %%              process, including registering a name for it.
 %%-----------------------------------------------------------------
 enter_loop(Mod, Options, State) ->
-    enter_loop(Mod, Options, State, self(), infinity).
+    enter_loop(Mod, Options, State, self(), infinity, undefined).
+
+enter_loop(Mod, Options, State, Backoff = {backoff, _, _ , _}) ->
+    enter_loop(Mod, Options, State, self(), infinity, Backoff);
 
 enter_loop(Mod, Options, State, ServerName = {_, _}) ->
-    enter_loop(Mod, Options, State, ServerName, infinity);
+    enter_loop(Mod, Options, State, ServerName, infinity, undefined);
 
 enter_loop(Mod, Options, State, Timeout) ->
-    enter_loop(Mod, Options, State, self(), Timeout).
+    enter_loop(Mod, Options, State, self(), Timeout, undefined).
+
+enter_loop(Mod, Options, State, ServerName, Backoff = {backoff, _, _, _}) ->
+    enter_loop(Mod, Options, State, ServerName, infinity, Backoff);
 
 enter_loop(Mod, Options, State, ServerName, Timeout) ->
+    enter_loop(Mod, Options, State, ServerName, Timeout, undefined).
+
+enter_loop(Mod, Options, State, ServerName, Timeout, Backoff) ->
     Name = get_proc_name(ServerName),
     Parent = get_parent(),
     Debug = debug_options(Name, Options),
     Queue = priority_queue:new(),
-    loop(Parent, Name, State, Mod, Timeout, Queue, Debug).
+    Backoff1 = extend_backoff(Backoff),
+    loop(Parent, Name, State, Mod, Timeout, Backoff1, Queue, Debug).
 
 %%%========================================================================
 %%% Gen-callback functions
@@ -329,23 +387,37 @@ enter_loop(Mod, Options, State, ServerName, Timeout) ->
 %%% ---------------------------------------------------
 init_it(Starter, self, Name, Mod, Args, Options) ->
     init_it(Starter, self(), Name, Mod, Args, Options);
-init_it(Starter, Parent, Name, Mod, Args, Options) ->
+init_it(Starter, Parent, Name0, Mod, Args, Options) ->
+    Name = name(Name0),
     Debug = debug_options(Name, Options),
     Queue = priority_queue:new(),
     case catch Mod:init(Args) of
 	{ok, State} ->
 	    proc_lib:init_ack(Starter, {ok, self()}), 	    
-	    loop(Parent, Name, State, Mod, infinity, Queue, Debug);
+	    loop(Parent, Name, State, Mod, infinity, undefined, Queue, Debug);
 	{ok, State, Timeout} ->
-	    proc_lib:init_ack(Starter, {ok, self()}), 	    
-	    loop(Parent, Name, State, Mod, Timeout, Queue, Debug);
+	    proc_lib:init_ack(Starter, {ok, self()}),
+	    loop(Parent, Name, State, Mod, Timeout, undefined, Queue, Debug);
+	{ok, State, Timeout, Backoff = {backoff, _, _, _}} ->
+            Backoff1 = extend_backoff(Backoff),
+	    proc_lib:init_ack(Starter, {ok, self()}),
+	    loop(Parent, Name, State, Mod, Timeout, Backoff1, Queue, Debug);
 	{stop, Reason} ->
+	    %% For consistency, we must make sure that the
+	    %% registered name (if any) is unregistered before
+	    %% the parent process is notified about the failure.
+	    %% (Otherwise, the parent process could get
+	    %% an 'already_started' error if it immediately
+	    %% tried starting the process again.)
+	    unregister_name(Name0),
 	    proc_lib:init_ack(Starter, {error, Reason}),
 	    exit(Reason);
 	ignore ->
+	    unregister_name(Name0),
 	    proc_lib:init_ack(Starter, ignore),
 	    exit(normal);
 	{'EXIT', Reason} ->
+	    unregister_name(Name0),
 	    proc_lib:init_ack(Starter, {error, Reason}),
 	    exit(Reason);
 	Else ->
@@ -354,33 +426,159 @@ init_it(Starter, Parent, Name, Mod, Args, Options) ->
 	    exit(Error)
     end.
 
+name({local,Name}) -> Name;
+name({global,Name}) -> Name;
+%% name(Pid) when is_pid(Pid) -> Pid;
+%% when R11 goes away, drop the line beneath and uncomment the line above
+name(Name) -> Name.
+
+unregister_name({local,Name}) ->
+    _ = (catch unregister(Name));
+unregister_name({global,Name}) ->
+    _ = global:unregister_name(Name);
+unregister_name(Pid) when is_pid(Pid) ->
+    Pid.
+
+extend_backoff(undefined) ->
+    undefined;
+extend_backoff({backoff, InitialTimeout, MinimumTimeout, DesiredHibPeriod}) ->
+    {backoff, InitialTimeout, MinimumTimeout, DesiredHibPeriod, now()}.
+
 %%%========================================================================
 %%% Internal functions
 %%%========================================================================
 %%% ---------------------------------------------------
 %%% The MAIN loop.
 %%% ---------------------------------------------------
-loop(Parent, Name, State, Mod, Time, Queue, Debug) ->
+loop(Parent, Name, State, Mod, hibernate, undefined, Queue, Debug) ->
+    pre_hibernate(Parent, Name, State, Mod, undefined, Queue, Debug);
+loop(Parent, Name, State, Mod, Time, TimeoutState, Queue, Debug) ->
+    process_next_msg(Parent, Name, State, Mod, Time, TimeoutState,
+                     drain(Queue), Debug).
+
+drain(Queue) ->
     receive
-        Input -> loop(Parent, Name, State, Mod,
-                      Time, in(Input, Queue), Debug)
-    after 0 ->
-            case priority_queue:out(Queue) of
-                {{value, Msg}, Queue1} ->
-                    process_msg(Parent, Name, State, Mod,
-                                Time, Queue1, Debug, Msg);
-                {empty, Queue1} ->
-                    receive
-                        Input ->
-                            loop(Parent, Name, State, Mod,
-                                 Time, in(Input, Queue1), Debug)
-                    after Time ->
-                            process_msg(Parent, Name, State, Mod,
-                                        Time, Queue1, Debug, timeout)
+        Input -> drain(in(Input, Queue))
+    after 0 -> Queue
+    end.
+
+process_next_msg(Parent, Name, State, Mod, Time, TimeoutState, Queue, Debug) ->
+    case priority_queue:out(Queue) of
+        {{value, Msg}, Queue1} ->
+            process_msg(Parent, Name, State, Mod,
+                        Time, TimeoutState, Queue1, Debug, Msg);
+        {empty, Queue1} ->
+            {Time1, HibOnTimeout}
+                = case {Time, TimeoutState} of
+                      {hibernate, {backoff, Current, _Min, _Desired, _RSt}} ->
+                          {Current, true};
+                      {hibernate, _} ->
+                          %% wake_hib/7 will set Time to hibernate. If
+                          %% we were woken and didn't receive a msg
+                          %% then we will get here and need a sensible
+                          %% value for Time1, otherwise we crash.
+                          %% R13B1 always waits infinitely when waking
+                          %% from hibernation, so that's what we do
+                          %% here too.
+                          {infinity, false};
+                      _ -> {Time, false}
+                  end,
+            receive
+                Input ->
+                    %% Time could be 'hibernate' here, so *don't* call loop
+                    process_next_msg(
+                      Parent, Name, State, Mod, Time, TimeoutState,
+                      drain(in(Input, Queue1)), Debug)
+            after Time1 ->
+                    case HibOnTimeout of
+                        true ->
+                            pre_hibernate(
+                              Parent, Name, State, Mod, TimeoutState, Queue1,
+                              Debug);
+                        false ->
+                            process_msg(
+                              Parent, Name, State, Mod, Time, TimeoutState,
+                              Queue1, Debug, timeout)
                     end
             end
     end.
 
+wake_hib(Parent, Name, State, Mod, TS, Queue, Debug) ->
+    TimeoutState1 = case TS of
+                        undefined ->
+                            undefined;
+                        {SleptAt, TimeoutState} ->
+                            adjust_timeout_state(SleptAt, now(), TimeoutState)
+                    end,
+    post_hibernate(Parent, Name, State, Mod, TimeoutState1,
+                   drain(Queue), Debug).
+
+hibernate(Parent, Name, State, Mod, TimeoutState, Queue, Debug) ->
+    TS = case TimeoutState of
+             undefined             -> undefined;
+             {backoff, _, _, _, _} -> {now(), TimeoutState}
+         end,
+    proc_lib:hibernate(?MODULE, wake_hib, [Parent, Name, State, Mod,
+                                           TS, Queue, Debug]).
+
+pre_hibernate(Parent, Name, State, Mod, TimeoutState, Queue, Debug) ->
+    case erlang:function_exported(Mod, handle_pre_hibernate, 1) of
+        true ->
+            case catch Mod:handle_pre_hibernate(State) of
+                {hibernate, NState} ->
+                    hibernate(Parent, Name, NState, Mod, TimeoutState, Queue,
+                              Debug);
+                Reply ->
+                    handle_common_termination(Reply, Name, pre_hibernate,
+                                              Mod, State, Debug)
+            end;
+        false ->
+            hibernate(Parent, Name, State, Mod, TimeoutState, Queue, Debug)
+    end.
+
+post_hibernate(Parent, Name, State, Mod, TimeoutState, Queue, Debug) ->
+    case erlang:function_exported(Mod, handle_post_hibernate, 1) of
+        true ->
+            case catch Mod:handle_post_hibernate(State) of
+                {noreply, NState} ->
+                    process_next_msg(Parent, Name, NState, Mod, infinity,
+                                     TimeoutState, Queue, Debug);
+                {noreply, NState, Time} ->
+                    process_next_msg(Parent, Name, NState, Mod, Time,
+                                     TimeoutState, Queue, Debug);
+                Reply ->
+                    handle_common_termination(Reply, Name, post_hibernate,
+                                              Mod, State, Debug)
+            end;
+        false ->
+            %% use hibernate here, not infinity. This matches
+            %% R13B. The key is that we should be able to get through
+            %% to process_msg calling sys:handle_system_msg with Time
+            %% still set to hibernate, iff that msg is the very msg
+            %% that woke us up (or the first msg we receive after
+            %% waking up).
+            process_next_msg(Parent, Name, State, Mod, hibernate,
+                             TimeoutState, Queue, Debug)
+    end.
+
+adjust_timeout_state(SleptAt, AwokeAt, {backoff, CurrentTO, MinimumTO,
+                                        DesiredHibPeriod, RandomState}) ->
+    NapLengthMicros = timer:now_diff(AwokeAt, SleptAt),
+    CurrentMicros = CurrentTO * 1000,
+    MinimumMicros = MinimumTO * 1000,
+    DesiredHibMicros = DesiredHibPeriod * 1000,
+    GapBetweenMessagesMicros = NapLengthMicros + CurrentMicros,
+    Base =
+        %% If enough time has passed between the last two messages then we
+        %% should consider sleeping sooner. Otherwise stay awake longer.
+        case GapBetweenMessagesMicros > (MinimumMicros + DesiredHibMicros) of
+            true -> lists:max([MinimumTO, CurrentTO div 2]);
+            false -> CurrentTO
+        end,
+    {Extra, RandomState1} = random:uniform_s(Base, RandomState),
+    CurrentTO1 = Base + Extra,
+    {backoff, CurrentTO1, MinimumTO, DesiredHibPeriod, RandomState1}.
+
 in({'$gen_pcast', {Priority, Msg}}, Queue) ->
     priority_queue:in({'$gen_cast', Msg}, Priority, Queue);
 in({'$gen_pcall', From, {Priority, Msg}}, Queue) ->
@@ -388,19 +586,25 @@ in({'$gen_pcall', From, {Priority, Msg}}, Queue) ->
 in(Input, Queue) ->
     priority_queue:in(Input, Queue).
 
-process_msg(Parent, Name, State, Mod, Time, Queue, Debug, Msg) ->
+process_msg(Parent, Name, State, Mod, Time, TimeoutState, Queue,
+            Debug, Msg) ->
     case Msg of
 	{system, From, Req} ->
-	    sys:handle_system_msg(Req, From, Parent, ?MODULE, Debug,
-				  [Name, State, Mod, Time, Queue]);
+	    sys:handle_system_msg
+              (Req, From, Parent, ?MODULE, Debug,
+               [Name, State, Mod, Time, TimeoutState, Queue]);
+        %% gen_server puts Hib on the end as the 7th arg, but that
+        %% version of the function seems not to be documented so
+        %% leaving out for now.
 	{'EXIT', Parent, Reason} ->
 	    terminate(Reason, Name, Msg, Mod, State, Debug);
 	_Msg when Debug =:= [] ->
-	    handle_msg(Msg, Parent, Name, State, Mod, Time, Queue);
+	    handle_msg(Msg, Parent, Name, State, Mod, TimeoutState, Queue);
 	_Msg ->
 	    Debug1 = sys:handle_debug(Debug, {?MODULE, print_event}, 
 				      Name, {in, Msg}),
-	    handle_msg(Msg, Parent, Name, State, Mod, Time, Queue, Debug1)
+	    handle_msg(Msg, Parent, Name, State, Mod, TimeoutState, Queue,
+                       Debug1)
     end.
 
 %%% ---------------------------------------------------
@@ -598,87 +802,95 @@ dispatch(Info, Mod, State) ->
     Mod:handle_info(Info, State).
 
 handle_msg({'$gen_call', From, Msg},
-           Parent, Name, State, Mod, _Time, Queue) ->
+           Parent, Name, State, Mod, TimeoutState, Queue) ->
     case catch Mod:handle_call(Msg, From, State) of
 	{reply, Reply, NState} ->
 	    reply(From, Reply),
-	    loop(Parent, Name, NState, Mod, infinity, Queue, []);
+	    loop(Parent, Name, NState, Mod, infinity, TimeoutState, Queue, []);
 	{reply, Reply, NState, Time1} ->
 	    reply(From, Reply),
-	    loop(Parent, Name, NState, Mod, Time1, Queue, []);
+	    loop(Parent, Name, NState, Mod, Time1, TimeoutState, Queue, []);
 	{noreply, NState} ->
-	    loop(Parent, Name, NState, Mod, infinity, Queue, []);
+	    loop(Parent, Name, NState, Mod, infinity, TimeoutState, Queue, []);
 	{noreply, NState, Time1} ->
-	    loop(Parent, Name, NState, Mod, Time1, Queue, []);
+	    loop(Parent, Name, NState, Mod, Time1, TimeoutState, Queue, []);
 	{stop, Reason, Reply, NState} ->
 	    {'EXIT', R} = 
 		(catch terminate(Reason, Name, Msg, Mod, NState, [])),
 	    reply(From, Reply),
 	    exit(R);
-	Other -> handle_common_reply(Other,
-                                     Parent, Name, Msg, Mod, State, Queue)
+	Other -> handle_common_reply(Other, Parent, Name, Msg, Mod, State,
+                                     TimeoutState, Queue)
     end;
 handle_msg(Msg,
-           Parent, Name, State, Mod, _Time, Queue) ->
+           Parent, Name, State, Mod, TimeoutState, Queue) ->
     Reply = (catch dispatch(Msg, Mod, State)),
-    handle_common_reply(Reply, Parent, Name, Msg, Mod, State, Queue).
+    handle_common_reply(Reply, Parent, Name, Msg, Mod, State,
+                        TimeoutState, Queue).
 
 handle_msg({'$gen_call', From, Msg},
-           Parent, Name, State, Mod, _Time, Queue, Debug) ->
+           Parent, Name, State, Mod, TimeoutState, Queue, Debug) ->
     case catch Mod:handle_call(Msg, From, State) of
 	{reply, Reply, NState} ->
 	    Debug1 = reply(Name, From, Reply, NState, Debug),
-	    loop(Parent, Name, NState, Mod, infinity, Queue, Debug1);
+	    loop(Parent, Name, NState, Mod, infinity, TimeoutState, Queue,
+                 Debug1);
 	{reply, Reply, NState, Time1} ->
 	    Debug1 = reply(Name, From, Reply, NState, Debug),
-	    loop(Parent, Name, NState, Mod, Time1, Queue, Debug1);
+	    loop(Parent, Name, NState, Mod, Time1, TimeoutState, Queue, Debug1);
 	{noreply, NState} ->
 	    Debug1 = sys:handle_debug(Debug, {?MODULE, print_event}, Name,
 				      {noreply, NState}),
-	    loop(Parent, Name, NState, Mod, infinity, Queue, Debug1);
+	    loop(Parent, Name, NState, Mod, infinity, TimeoutState, Queue,
+                 Debug1);
 	{noreply, NState, Time1} ->
 	    Debug1 = sys:handle_debug(Debug, {?MODULE, print_event}, Name,
 				      {noreply, NState}),
-	    loop(Parent, Name, NState, Mod, Time1, Queue, Debug1);
+	    loop(Parent, Name, NState, Mod, Time1, TimeoutState, Queue, Debug1);
 	{stop, Reason, Reply, NState} ->
 	    {'EXIT', R} = 
 		(catch terminate(Reason, Name, Msg, Mod, NState, Debug)),
 	    reply(Name, From, Reply, NState, Debug),
 	    exit(R);
 	Other ->
-	    handle_common_reply(Other,
-                                Parent, Name, Msg, Mod, State, Queue, Debug)
+	    handle_common_reply(Other, Parent, Name, Msg, Mod, State,
+                                TimeoutState, Queue, Debug)
     end;
 handle_msg(Msg,
-           Parent, Name, State, Mod, _Time, Queue, Debug) ->
+           Parent, Name, State, Mod, TimeoutState, Queue, Debug) ->
     Reply = (catch dispatch(Msg, Mod, State)),
-    handle_common_reply(Reply,
-                        Parent, Name, Msg, Mod, State, Queue, Debug).
+    handle_common_reply(Reply, Parent, Name, Msg, Mod, State,
+                        TimeoutState, Queue, Debug).
 
-handle_common_reply(Reply, Parent, Name, Msg, Mod, State, Queue) ->
+handle_common_reply(Reply, Parent, Name, Msg, Mod, State,
+                    TimeoutState, Queue) ->
     case Reply of
 	{noreply, NState} ->
-	    loop(Parent, Name, NState, Mod, infinity, Queue, []);
+	    loop(Parent, Name, NState, Mod, infinity, TimeoutState, Queue, []);
 	{noreply, NState, Time1} ->
-	    loop(Parent, Name, NState, Mod, Time1, Queue, []);
-	{stop, Reason, NState} ->
-	    terminate(Reason, Name, Msg, Mod, NState, []);
-	{'EXIT', What} ->
-	    terminate(What, Name, Msg, Mod, State, []);
-	_ ->
-	    terminate({bad_return_value, Reply}, Name, Msg, Mod, State, [])
+	    loop(Parent, Name, NState, Mod, Time1, TimeoutState, Queue, []);
+        _ ->
+            handle_common_termination(Reply, Name, Msg, Mod, State, [])
     end.
 
-handle_common_reply(Reply, Parent, Name, Msg, Mod, State, Queue, Debug) ->
+handle_common_reply(Reply, Parent, Name, Msg, Mod, State, TimeoutState, Queue,
+                    Debug) ->
     case Reply of
 	{noreply, NState} ->
 	    Debug1 = sys:handle_debug(Debug, {?MODULE, print_event}, Name,
 				      {noreply, NState}),
-	    loop(Parent, Name, NState, Mod, infinity, Queue, Debug1);
+	    loop(Parent, Name, NState, Mod, infinity, TimeoutState, Queue,
+                 Debug1);
 	{noreply, NState, Time1} ->
 	    Debug1 = sys:handle_debug(Debug, {?MODULE, print_event}, Name,
 				      {noreply, NState}),
-	    loop(Parent, Name, NState, Mod, Time1, Queue, Debug1);
+	    loop(Parent, Name, NState, Mod, Time1, TimeoutState, Queue, Debug1);
+        _ ->
+            handle_common_termination(Reply, Name, Msg, Mod, State, Debug)
+    end.
+
+handle_common_termination(Reply, Name, Msg, Mod, State, Debug) ->
+    case Reply of
 	{stop, Reason, NState} ->
 	    terminate(Reason, Name, Msg, Mod, NState, Debug);
 	{'EXIT', What} ->
@@ -696,16 +908,24 @@ reply(Name, {To, Tag}, Reply, State, Debug) ->
 %%-----------------------------------------------------------------
 %% Callback functions for system messages handling.
 %%-----------------------------------------------------------------
-system_continue(Parent, Debug, [Name, State, Mod, Time, Queue]) ->
-    loop(Parent, Name, State, Mod, Time, Queue, Debug).
+system_continue(Parent, Debug, [Name, State, Mod, Time, TimeoutState, Queue]) ->
+    loop(Parent, Name, State, Mod, Time, TimeoutState, Queue, Debug).
 
-system_terminate(Reason, _Parent, Debug, [Name, State, Mod, _Time, _Queue]) ->
+-ifdef(use_specs).
+-spec system_terminate(_, _, _, [_]) -> no_return().
+-endif.
+
+system_terminate(Reason, _Parent, Debug, [Name, State, Mod, _Time,
+                                          _TimeoutState, _Queue]) ->
     terminate(Reason, Name, [], Mod, State, Debug).
 
-system_code_change([Name, State, Mod, Time, Queue], _Module, OldVsn, Extra) ->
+system_code_change([Name, State, Mod, Time, TimeoutState, Queue], _Module,
+                   OldVsn, Extra) ->
     case catch Mod:code_change(OldVsn, State, Extra) of
-	{ok, NewState} -> {ok, [Name, NewState, Mod, Time, Queue]};
-	Else -> Else
+	{ok, NewState} ->
+            {ok, [Name, NewState, Mod, Time, TimeoutState, Queue]};
+	Else ->
+            Else
     end.
 
 %%-----------------------------------------------------------------
@@ -747,6 +967,8 @@ terminate(Reason, Name, Msg, Mod, State, Debug) ->
 		    exit(normal);
 		shutdown ->
 		    exit(shutdown);
+		{shutdown,_}=Shutdown ->
+		    exit(Shutdown);
 		_ ->
 		    error_info(Reason, Name, Msg, State, Debug),
 		    exit(Reason)
@@ -871,8 +1093,8 @@ name_to_pid(Name) ->
 %% Status information
 %%-----------------------------------------------------------------
 format_status(Opt, StatusData) ->
-    [PDict, SysState, Parent, Debug, [Name, State, Mod, _Time, Queue]] =
-        StatusData,
+    [PDict, SysState, Parent, Debug,
+     [Name, State, Mod, _Time, _TimeoutState, Queue]] = StatusData,
     NameTag = if is_pid(Name) ->
 		      pid_to_list(Name);
 		 is_atom(Name) ->
diff --git a/src/rabbit_amqqueue_process.erl b/src/rabbit_amqqueue_process.erl
index cf0ef44f..fe2e8509 100644
--- a/src/rabbit_amqqueue_process.erl
+++ b/src/rabbit_amqqueue_process.erl
@@ -36,7 +36,8 @@
 -behaviour(gen_server2).
 
 -define(UNSENT_MESSAGE_LIMIT, 100).
--define(HIBERNATE_AFTER, 1000).
+-define(HIBERNATE_AFTER_MIN, 1000).
+-define(DESIRED_HIBERNATE, 10000).
 
 -export([start_link/1]).
 
@@ -101,7 +102,8 @@ init(Q) ->
             next_msg_id = 1,
             message_buffer = queue:new(),
             active_consumers = queue:new(),
-            blocked_consumers = queue:new()}, ?HIBERNATE_AFTER}.
+            blocked_consumers = queue:new()}, hibernate,
+     {backoff, ?HIBERNATE_AFTER_MIN, ?HIBERNATE_AFTER_MIN, ?DESIRED_HIBERNATE}}.
 
 terminate(_Reason, State) ->
     %% FIXME: How do we cancel active subscriptions?
@@ -116,9 +118,9 @@ code_change(_OldVsn, State, _Extra) ->
 
 %%----------------------------------------------------------------------------
 
-reply(Reply, NewState) -> {reply, Reply, NewState, ?HIBERNATE_AFTER}.
+reply(Reply, NewState) -> {reply, Reply, NewState, hibernate}.
 
-noreply(NewState) -> {noreply, NewState, ?HIBERNATE_AFTER}.
+noreply(NewState) -> {noreply, NewState, hibernate}.
 
 lookup_ch(ChPid) ->
     case get({ch, ChPid}) of
@@ -813,11 +815,6 @@ handle_info({'DOWN', MonitorRef, process, DownPid, _Reason},
 handle_info({'DOWN', _MonitorRef, process, DownPid, _Reason}, State) ->
     handle_ch_down(DownPid, State);
 
-handle_info(timeout, State) ->
-    %% TODO: Once we drop support for R11B-5, we can change this to
-    %% {noreply, State, hibernate};
-    proc_lib:hibernate(gen_server2, enter_loop, [?MODULE, [], State]);
-
 handle_info(Info, State) ->
     ?LOGDEBUG("Info in queue: ~p~n", [Info]),
     {stop, {unhandled_info, Info}, State}.
diff --git a/src/rabbit_channel.erl b/src/rabbit_channel.erl
index 87664de3..58b94234 100644
--- a/src/rabbit_channel.erl
+++ b/src/rabbit_channel.erl
@@ -162,9 +162,7 @@ handle_info({'EXIT', _Pid, Reason}, State) ->
 
 handle_info(timeout, State) ->
     ok = clear_permission_cache(),
-    %% TODO: Once we drop support for R11B-5, we can change this to
-    %% {noreply, State, hibernate};
-    proc_lib:hibernate(gen_server2, enter_loop, [?MODULE, [], State]).
+    {noreply, State, hibernate}.
 
 terminate(_Reason, #ch{writer_pid = WriterPid, limiter_pid = LimiterPid,
                        state = terminating}) ->