Merge pull request #1407 from eltex-ecss/auto_hibernate_timeout

Add option hibernate_after to gen_server, gen_statem and gen_event. 
Also added to the deprecated gen_fsm behaviour.

OTP14405

13 files changed, 459 insertions, 135 deletions

diff --git a/lib/stdlib/doc/src/gen_event.xml b/lib/stdlib/doc/src/gen_event.xml
index 09bde3e397..012737c390 100644
--- a/lib/stdlib/doc/src/gen_event.xml
+++ b/lib/stdlib/doc/src/gen_event.xml
@@ -358,7 +358,7 @@ gen_event:stop             ----->  Module:terminate/2
         <v>&nbsp;Name = atom()</v>
         <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Options = [Option]</v>
-        <v>&nbsp;Option = {debug,Dbgs} | {timeout,Time} | {spawn_opt,SOpts}</v>
+        <v>&nbsp;Option = {debug,Dbgs} | {timeout,Time} | {hibernate_after,HibernateAfterTimeout} | {spawn_opt,SOpts}</v>
         <v>&nbsp;&nbsp;Dbgs = [Dbg]</v>
         <v>&nbsp;&nbsp;&nbsp;Dbg = trace | log | statistics | {log_to_file,FileName} | {install,{Func,FuncState}}</v>
         <v>&nbsp;&nbsp;SOpts = [term()]</v>
@@ -385,7 +385,7 @@ gen_event:stop             ----->  Module:terminate/2
         <v>&nbsp;Name = atom()</v>
         <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Options = [Option]</v>
-        <v>&nbsp;Option = {debug,Dbgs} | {timeout,Time} | {spawn_opt,SOpts}</v>
+        <v>&nbsp;Option = {debug,Dbgs} | {timeout,Time} | {hibernate_after,HibernateAfterTimeout} | {spawn_opt,SOpts}</v>
         <v>&nbsp;&nbsp;Dbgs = [Dbg]</v>
         <v>&nbsp;&nbsp;&nbsp;Dbg = trace | log | statistics | {log_to_file,FileName} | {install,{Func,FuncState}}</v>
         <v>&nbsp;&nbsp;SOpts = [term()]</v>
@@ -419,6 +419,12 @@ gen_event:stop             ----->  Module:terminate/2
               <seealso marker="kernel:global"><c>global</c></seealso>.
               Thus, <c>{via,global,GlobalName}</c> is a valid reference.</p>
           </item>
+          <item>
+            <p>If option <c>{hibernate_after,HibernateAfterTimeout}</c> is present, the <c>gen_event</c>
+              process awaits any message for <c>HibernateAfterTimeout</c> milliseconds and
+              if no message is received, the process goes into hibernation automatically
+              (by calling <seealso marker="proc_lib#hibernate/3"><c>proc_lib:hibernate/3</c></seealso>).</p>
+          </item>
         </list>
         <p>If the event manager is successfully created, the function
           returns <c>{ok,Pid}</c>, where <c>Pid</c> is the pid of
diff --git a/lib/stdlib/doc/src/gen_server.xml b/lib/stdlib/doc/src/gen_server.xml
index a8006bb870..7d137fc772 100644
--- a/lib/stdlib/doc/src/gen_server.xml
+++ b/lib/stdlib/doc/src/gen_server.xml
@@ -199,7 +199,7 @@ gen_server:abcast     -----> Module:handle_cast/2
       <type>
         <v>Module = atom()</v>
         <v>Options = [Option]</v>
-        <v>&nbsp;Option = {debug,Dbgs}</v>
+        <v>&nbsp;Option = {debug,Dbgs} | {hibernate_after,HibernateAfterTimeout}</v>
         <v>&nbsp;&nbsp;Dbgs = [Dbg]</v>
         <v>&nbsp;&nbsp;&nbsp;Dbg = trace | log | statistics</v>
         <v>&nbsp;&nbsp;&nbsp;&nbsp;| {log_to_file,FileName} | {install,{Func,FuncState}}</v>
@@ -334,7 +334,7 @@ gen_server:abcast     -----> Module:handle_cast/2
         <v>Module = atom()</v>
         <v>Args = term()</v>
         <v>Options = [Option]</v>
-        <v>&nbsp;Option = {debug,Dbgs} | {timeout,Time} | {spawn_opt,SOpts}</v>
+        <v>&nbsp;Option = {debug,Dbgs} | {timeout,Time} | {hibernate_after,HibernateAfterTimeout} | {spawn_opt,SOpts}</v>
         <v>&nbsp;&nbsp;Dbgs = [Dbg]</v>
         <v>&nbsp;&nbsp;&nbsp;Dbg = trace | log | statistics | {log_to_file,FileName} | {install,{Func,FuncState}}</v>
         <v>&nbsp;&nbsp;SOpts = [term()]</v>
@@ -364,7 +364,7 @@ gen_server:abcast     -----> Module:handle_cast/2
         <v>Module = atom()</v>
         <v>Args = term()</v>
         <v>Options = [Option]</v>
-        <v>&nbsp;Option = {debug,Dbgs} | {timeout,Time} | {spawn_opt,SOpts}</v>
+        <v>&nbsp;Option = {debug,Dbgs} | {timeout,Time} | {hibernate_after,HibernateAfterTimeout} | {spawn_opt,SOpts}</v>
         <v>&nbsp;&nbsp;Dbgs = [Dbg]</v>
         <v>&nbsp;&nbsp;&nbsp;Dbg = trace | log | statistics | {log_to_file,FileName} | {install,{Func,FuncState}}</v>
         <v>&nbsp;&nbsp;SOpts = [term()]</v>
@@ -417,6 +417,12 @@ gen_server:abcast     -----> Module:handle_cast/2
               returns <c>{error,timeout}</c>.</p>
           </item>
           <item>
+            <p>If option <c>{hibernate_after,HibernateAfterTimeout}</c> is present, the <c>gen_server</c>
+              process awaits any message for <c>HibernateAfterTimeout</c> milliseconds and
+              if no message is received, the process goes into hibernation automatically
+              (by calling <seealso marker="proc_lib#hibernate/3"><c>proc_lib:hibernate/3</c></seealso>).</p>
+          </item>
+          <item>
             <p>If option <c>{debug,Dbgs}</c> is present,
               the corresponding <c>sys</c> function is called for each
               item in <c>Dbgs</c>; see
diff --git a/lib/stdlib/doc/src/gen_statem.xml b/lib/stdlib/doc/src/gen_statem.xml
index 17a3a3c83c..1aac88c308 100644
--- a/lib/stdlib/doc/src/gen_statem.xml
+++ b/lib/stdlib/doc/src/gen_statem.xml
@@ -453,6 +453,21 @@ handle_event(_, _, State, Data) ->
       </desc>
     </datatype>
     <datatype>
+      <name name="hibernate_after_opt"/>
+      <desc>
+	<p>
+          hibernate_after option that can be used when starting
+	  a <c>gen_statem</c> server through,
+	  <seealso marker="#enter_loop/4"><c>enter_loop/4-6</c></seealso>.
+	</p>
+    <p>If option<seealso marker="#type-hibernate_after_opt"><c>{hibernate_after,HibernateAfterTimeout}</c></seealso> is present, the <c>gen_statem</c>
+        process awaits any message for <c>HibernateAfterTimeout</c> milliseconds and
+        if no message is received, the process goes into hibernation automatically
+        (by calling <seealso marker="proc_lib#hibernate/3"><c>proc_lib:hibernate/3</c></seealso>).
+    </p>
+      </desc>
+    </datatype>
+    <datatype>
       <name name="start_opt"/>
       <desc>
 	<p>
@@ -1551,6 +1566,13 @@ handle_event(_, _, State, Data) ->
             </p>
           </item>
           <item>
+            <p>If option<seealso marker="#type-hibernate_after_opt"><c>{hibernate_after,HibernateAfterTimeout}</c></seealso> is present, the <c>gen_statem</c>
+              process awaits any message for <c>HibernateAfterTimeout</c> milliseconds and
+              if no message is received, the process goes into hibernation automatically
+              (by calling <seealso marker="proc_lib#hibernate/3"><c>proc_lib:hibernate/3</c></seealso>).
+            </p>
+          </item>
+          <item>
             <p>
               If option
               <seealso marker="#type-debug_opt"><c>{debug,Dbgs}</c></seealso>
diff --git a/lib/stdlib/src/gen.erl b/lib/stdlib/src/gen.erl
index 597830cf9a..257c829801 100644
--- a/lib/stdlib/src/gen.erl
+++ b/lib/stdlib/src/gen.erl
@@ -26,7 +26,7 @@
 %%%
 %%% The standard behaviour should export init_it/6.
 %%%-----------------------------------------------------------------
--export([start/5, start/6, debug_options/2,
+-export([start/5, start/6, debug_options/2, hibernate_after/1,
 	 name/1, unregister_name/1, get_proc_name/1, get_parent/0,
 	 call/3, call/4, reply/2, stop/1, stop/3]).
 
@@ -408,6 +408,14 @@ spawn_opts(Options) ->
 	    []
     end.
 
+hibernate_after(Options) ->
+	case lists:keyfind(hibernate_after, 1, Options) of
+		{_,HibernateAfterTimeout} ->
+			HibernateAfterTimeout;
+		false ->
+			infinity
+	end.
+
 debug_options(Name, Opts) ->
     case lists:keyfind(debug, 1, Opts) of
 	{_,Options} ->
diff --git a/lib/stdlib/src/gen_event.erl b/lib/stdlib/src/gen_event.erl
index 4c80464680..da2b0da3ca 100644
--- a/lib/stdlib/src/gen_event.erl
+++ b/lib/stdlib/src/gen_event.erl
@@ -37,7 +37,7 @@
          stop/1, stop/3,
 	 notify/2, sync_notify/2,
 	 add_handler/3, add_sup_handler/3, delete_handler/3, swap_handler/3,
-	 swap_sup_handler/3, which_handlers/1, call/3, call/4, wake_hib/4]).
+	 swap_sup_handler/3, which_handlers/1, call/3, call/4, wake_hib/5]).
 
 -export([init_it/6,
 	 system_continue/3,
@@ -186,8 +186,9 @@ init_it(Starter, Parent, Name0, _, _, Options) ->
     process_flag(trap_exit, true),
     Name = gen:name(Name0),
     Debug = gen:debug_options(Name, Options),
+	HibernateAfterTimeout = gen:hibernate_after(Options),
     proc_lib:init_ack(Starter, {ok, self()}),
-    loop(Parent, Name, [], Debug, false).
+    loop(Parent, Name, [], HibernateAfterTimeout, Debug, false).
 
 -spec add_handler(emgr_ref(), handler(), term()) -> term().
 add_handler(M, Handler, Args) -> rpc(M, {add_handler, Handler, Args}).
@@ -264,81 +265,83 @@ send(M, Cmd) ->
     M ! Cmd,
     ok.
 
-loop(Parent, ServerName, MSL, Debug, true) ->
-     proc_lib:hibernate(?MODULE, wake_hib, [Parent, ServerName, MSL, Debug]);
-loop(Parent, ServerName, MSL, Debug, _) ->
-    fetch_msg(Parent, ServerName, MSL, Debug, false).
+loop(Parent, ServerName, MSL, HibernateAfterTimeout, Debug, true) ->
+     proc_lib:hibernate(?MODULE, wake_hib, [Parent, ServerName, MSL, HibernateAfterTimeout, Debug]);
+loop(Parent, ServerName, MSL, HibernateAfterTimeout, Debug, _) ->
+    fetch_msg(Parent, ServerName, MSL, HibernateAfterTimeout, Debug, false).
 
-wake_hib(Parent, ServerName, MSL, Debug) ->
-    fetch_msg(Parent, ServerName, MSL, Debug, true).
+wake_hib(Parent, ServerName, MSL, HibernateAfterTimeout, Debug) ->
+    fetch_msg(Parent, ServerName, MSL, HibernateAfterTimeout, Debug, true).
 
-fetch_msg(Parent, ServerName, MSL, Debug, Hib) ->
+fetch_msg(Parent, ServerName, MSL, HibernateAfterTimeout, Debug, Hib) ->
     receive
 	{system, From, Req} ->
 	    sys:handle_system_msg(Req, From, Parent, ?MODULE, Debug,
-				  [ServerName, MSL, Hib],Hib);
+				  [ServerName, MSL, HibernateAfterTimeout, Hib],Hib);
 	{'EXIT', Parent, Reason} ->
 	    terminate_server(Reason, Parent, MSL, ServerName);
 	Msg when Debug =:= [] ->
-	    handle_msg(Msg, Parent, ServerName, MSL, []);
+	    handle_msg(Msg, Parent, ServerName, MSL, HibernateAfterTimeout, []);
 	Msg ->
 	    Debug1 = sys:handle_debug(Debug, fun print_event/3,
 				      ServerName, {in, Msg}),
-	    handle_msg(Msg, Parent, ServerName, MSL, Debug1)
+	    handle_msg(Msg, Parent, ServerName, MSL, HibernateAfterTimeout, Debug1)
+    after HibernateAfterTimeout ->
+	    loop(Parent, ServerName, MSL, HibernateAfterTimeout, Debug, true)
     end.
 
-handle_msg(Msg, Parent, ServerName, MSL, Debug) ->
+handle_msg(Msg, Parent, ServerName, MSL, HibernateAfterTimeout, Debug) ->
     case Msg of
 	{notify, Event} ->
 	    {Hib,MSL1} = server_notify(Event, handle_event, MSL, ServerName),
-	    loop(Parent, ServerName, MSL1, Debug, Hib);
+	    loop(Parent, ServerName, MSL1, HibernateAfterTimeout, Debug, Hib);
 	{_From, Tag, {sync_notify, Event}} ->
 	    {Hib, MSL1} = server_notify(Event, handle_event, MSL, ServerName),
 	    reply(Tag, ok),
-	    loop(Parent, ServerName, MSL1, Debug, Hib);
+	    loop(Parent, ServerName, MSL1, HibernateAfterTimeout, Debug, Hib);
 	{'EXIT', From, Reason} ->
 	    MSL1 = handle_exit(From, Reason, MSL, ServerName),
-	    loop(Parent, ServerName, MSL1, Debug, false);
+	    loop(Parent, ServerName, MSL1, HibernateAfterTimeout, Debug, false);
 	{_From, Tag, {call, Handler, Query}} ->
 	    {Hib, Reply, MSL1} = server_call(Handler, Query, MSL, ServerName),
 	    reply(Tag, Reply),
-	    loop(Parent, ServerName, MSL1, Debug, Hib);
+	    loop(Parent, ServerName, MSL1, HibernateAfterTimeout, Debug, Hib);
 	{_From, Tag, {add_handler, Handler, Args}} ->
 	    {Hib, Reply, MSL1} = server_add_handler(Handler, Args, MSL),
 	    reply(Tag, Reply),
-	    loop(Parent, ServerName, MSL1, Debug, Hib);
+	    loop(Parent, ServerName, MSL1, HibernateAfterTimeout, Debug, Hib);
 	{_From, Tag, {add_sup_handler, Handler, Args, SupP}} ->
 	    {Hib, Reply, MSL1} = server_add_sup_handler(Handler, Args, MSL, SupP),
 	    reply(Tag, Reply),
-	    loop(Parent, ServerName, MSL1, Debug, Hib);
+	    loop(Parent, ServerName, MSL1, HibernateAfterTimeout, Debug, Hib);
 	{_From, Tag, {delete_handler, Handler, Args}} ->
 	    {Reply, MSL1} = server_delete_handler(Handler, Args, MSL,
 						  ServerName),
 	    reply(Tag, Reply),
-	    loop(Parent, ServerName, MSL1, Debug, false);
+	    loop(Parent, ServerName, MSL1, HibernateAfterTimeout, Debug, false);
 	{_From, Tag, {swap_handler, Handler1, Args1, Handler2, Args2}} ->
 	    {Hib, Reply, MSL1} = server_swap_handler(Handler1, Args1, Handler2,
 						     Args2, MSL, ServerName),
 	    reply(Tag, Reply),
-	    loop(Parent, ServerName, MSL1, Debug, Hib);
+	    loop(Parent, ServerName, MSL1, HibernateAfterTimeout, Debug, Hib);
 	{_From, Tag, {swap_sup_handler, Handler1, Args1, Handler2, Args2,
 		     Sup}} ->
 	    {Hib, Reply, MSL1} = server_swap_handler(Handler1, Args1, Handler2,
 						Args2, MSL, Sup, ServerName),
 	    reply(Tag, Reply),
-	    loop(Parent, ServerName, MSL1, Debug, Hib);
+	    loop(Parent, ServerName, MSL1, HibernateAfterTimeout, Debug, Hib);
 	{_From, Tag, stop} ->
 	    catch terminate_server(normal, Parent, MSL, ServerName),
 	    reply(Tag, ok);
 	{_From, Tag, which_handlers} ->
 	    reply(Tag, the_handlers(MSL)),
-	    loop(Parent, ServerName, MSL, Debug, false);
+	    loop(Parent, ServerName, MSL, HibernateAfterTimeout, Debug, false);
 	{_From, Tag, get_modules} ->
 	    reply(Tag, get_modules(MSL)),
-	    loop(Parent, ServerName, MSL, Debug, false);
+	    loop(Parent, ServerName, MSL, HibernateAfterTimeout, Debug, false);
 	Other  ->
 	    {Hib, MSL1} = server_notify(Other, handle_info, MSL, ServerName),
-	    loop(Parent, ServerName, MSL1, Debug, Hib)
+	    loop(Parent, ServerName, MSL1, HibernateAfterTimeout, Debug, Hib)
     end.
 
 terminate_server(Reason, Parent, MSL, ServerName) ->
@@ -392,18 +395,18 @@ terminate_supervised(Pid, Reason, MSL, SName) ->
 %%-----------------------------------------------------------------
 %% Callback functions for system messages handling.
 %%-----------------------------------------------------------------
-system_continue(Parent, Debug, [ServerName, MSL, Hib]) ->
-    loop(Parent, ServerName, MSL, Debug, Hib).
+system_continue(Parent, Debug, [ServerName, MSL, HibernateAfterTimeout, Hib]) ->
+    loop(Parent, ServerName, MSL, HibernateAfterTimeout, Debug, Hib).
 
 -spec system_terminate(_, _, _, [_]) -> no_return().
-system_terminate(Reason, Parent, _Debug, [ServerName, MSL, _Hib]) ->
+system_terminate(Reason, Parent, _Debug, [ServerName, MSL, _HibernateAfterTimeout, _Hib]) ->
     terminate_server(Reason, Parent, MSL, ServerName).
 
 %%-----------------------------------------------------------------
 %% Module here is sent in the system msg change_code.  It specifies
 %% which module should be changed.
 %%-----------------------------------------------------------------
-system_code_change([ServerName, MSL, Hib], Module, OldVsn, Extra) ->
+system_code_change([ServerName, MSL, HibernateAfterTimeout, Hib], Module, OldVsn, Extra) ->
     MSL1 = lists:zf(fun(H) when H#handler.module =:= Module ->
 			    {ok, NewState} =
 				Module:code_change(OldVsn,
@@ -412,12 +415,12 @@ system_code_change([ServerName, MSL, Hib], Module, OldVsn, Extra) ->
 		       (_) -> true
 		    end,
 		    MSL),
-    {ok, [ServerName, MSL1, Hib]}.
+    {ok, [ServerName, MSL1, HibernateAfterTimeout, Hib]}.
 
-system_get_state([_ServerName, MSL, _Hib]) ->
+system_get_state([_ServerName, MSL, _HibernateAfterTimeout, _Hib]) ->
     {ok, [{Mod,Id,State} || #handler{module=Mod, id=Id, state=State} <- MSL]}.
 
-system_replace_state(StateFun, [ServerName, MSL, Hib]) ->
+system_replace_state(StateFun, [ServerName, MSL, HibernateAfterTimeout, Hib]) ->
     {NMSL, NStates} =
 		lists:unzip([begin
 				 Cur = {Mod,Id,State},
@@ -429,7 +432,7 @@ system_replace_state(StateFun, [ServerName, MSL, Hib]) ->
 					 {HS, Cur}
 				 end
 			     end || #handler{module=Mod, id=Id, state=State}=HS <- MSL]),
-    {ok, NStates, [ServerName, NMSL, Hib]}.
+    {ok, NStates, [ServerName, NMSL, HibernateAfterTimeout, Hib]}.
 
 %%-----------------------------------------------------------------
 %% Format debug messages.  Print them as the call-back module sees
@@ -798,7 +801,7 @@ get_modules(MSL) ->
 %% Status information
 %%-----------------------------------------------------------------
 format_status(Opt, StatusData) ->
-    [PDict, SysState, Parent, _Debug, [ServerName, MSL, _Hib]] = StatusData,
+    [PDict, SysState, Parent, _Debug, [ServerName, MSL, _HibernateAfterTimeout, _Hib]] = StatusData,
     Header = gen:format_status_header("Status for event handler",
                                       ServerName),
     FmtMSL = [case erlang:function_exported(Mod, format_status, 2) of
diff --git a/lib/stdlib/src/gen_fsm.erl b/lib/stdlib/src/gen_fsm.erl
index f9d4286a7c..9ef0ca818c 100644
--- a/lib/stdlib/src/gen_fsm.erl
+++ b/lib/stdlib/src/gen_fsm.erl
@@ -113,7 +113,7 @@
 	 sync_send_all_state_event/2, sync_send_all_state_event/3,
 	 reply/2,
 	 start_timer/2,send_event_after/2,cancel_timer/1,
-	 enter_loop/4, enter_loop/5, enter_loop/6, wake_hib/6]).
+	 enter_loop/4, enter_loop/5, enter_loop/6, wake_hib/7]).
 
 %% Internal exports
 -export([init_it/6,
@@ -329,7 +329,8 @@ enter_loop(Mod, Options, StateName, StateData, ServerName, Timeout) ->
     Name = gen:get_proc_name(ServerName),
     Parent = gen:get_parent(),
     Debug = gen:debug_options(Name, Options),
-    loop(Parent, Name, StateName, StateData, Mod, Timeout, Debug).
+	HibernateAfterTimeout = gen:hibernate_after(Options),
+    loop(Parent, Name, StateName, StateData, Mod, Timeout, HibernateAfterTimeout, Debug).
 
 %%% ---------------------------------------------------
 %%% Initiate the new process.
@@ -343,13 +344,14 @@ init_it(Starter, self, Name, Mod, Args, Options) ->
 init_it(Starter, Parent, Name0, Mod, Args, Options) ->
     Name = gen:name(Name0),
     Debug = gen:debug_options(Name, Options),
-    case catch Mod:init(Args) of
+	HibernateAfterTimeout = gen:hibernate_after(Options),
+	case catch Mod:init(Args) of
 	{ok, StateName, StateData} ->
 	    proc_lib:init_ack(Starter, {ok, self()}), 	    
-	    loop(Parent, Name, StateName, StateData, Mod, infinity, Debug);
+	    loop(Parent, Name, StateName, StateData, Mod, infinity, HibernateAfterTimeout, Debug);
 	{ok, StateName, StateData, Timeout} ->
 	    proc_lib:init_ack(Starter, {ok, self()}), 	    
-	    loop(Parent, Name, StateName, StateData, Mod, Timeout, Debug);
+	    loop(Parent, Name, StateName, StateData, Mod, Timeout, HibernateAfterTimeout, Debug);
 	{stop, Reason} ->
 	    gen:unregister_name(Name0),
 	    proc_lib:init_ack(Starter, {error, Reason}),
@@ -371,68 +373,77 @@ init_it(Starter, Parent, Name0, Mod, Args, Options) ->
 %%-----------------------------------------------------------------
 %% The MAIN loop
 %%-----------------------------------------------------------------
-loop(Parent, Name, StateName, StateData, Mod, hibernate, Debug) ->
+loop(Parent, Name, StateName, StateData, Mod, hibernate, HibernateAfterTimeout, Debug) ->
     proc_lib:hibernate(?MODULE,wake_hib,
-		       [Parent, Name, StateName, StateData, Mod, 
+		       [Parent, Name, StateName, StateData, Mod, HibernateAfterTimeout,
 			Debug]);
-loop(Parent, Name, StateName, StateData, Mod, Time, Debug) ->
+
+loop(Parent, Name, StateName, StateData, Mod, infinity, HibernateAfterTimeout, Debug) ->
+	receive
+		Msg ->
+			decode_msg(Msg,Parent, Name, StateName, StateData, Mod, infinity, HibernateAfterTimeout, Debug, false)
+	after HibernateAfterTimeout ->
+		loop(Parent, Name, StateName, StateData, Mod, hibernate, HibernateAfterTimeout, Debug)
+	end;
+
+loop(Parent, Name, StateName, StateData, Mod, Time, HibernateAfterTimeout, Debug) ->
     Msg = receive
 	      Input ->
 		    Input
 	  after Time ->
 		  {'$gen_event', timeout}
 	  end,
-    decode_msg(Msg,Parent, Name, StateName, StateData, Mod, Time, Debug, false).
+    decode_msg(Msg,Parent, Name, StateName, StateData, Mod, Time, HibernateAfterTimeout, Debug, false).
 
-wake_hib(Parent, Name, StateName, StateData, Mod, Debug) ->
+wake_hib(Parent, Name, StateName, StateData, Mod, HibernateAfterTimeout, Debug) ->
     Msg = receive
 	      Input ->
 		  Input
 	  end,
-    decode_msg(Msg, Parent, Name, StateName, StateData, Mod, hibernate, Debug, true).
+    decode_msg(Msg, Parent, Name, StateName, StateData, Mod, hibernate, HibernateAfterTimeout, Debug, true).
 
-decode_msg(Msg,Parent, Name, StateName, StateData, Mod, Time, Debug, Hib) ->
+decode_msg(Msg,Parent, Name, StateName, StateData, Mod, Time, HibernateAfterTimeout, Debug, Hib) ->
     case Msg of
         {system, From, Req} ->
 	    sys:handle_system_msg(Req, From, Parent, ?MODULE, Debug,
-				  [Name, StateName, StateData, Mod, Time], Hib);
+				  [Name, StateName, StateData, Mod, Time, HibernateAfterTimeout], Hib);
 	{'EXIT', Parent, Reason} ->
 	    terminate(Reason, Name, Msg, Mod, StateName, StateData, Debug);
 	_Msg when Debug =:= [] ->
-	    handle_msg(Msg, Parent, Name, StateName, StateData, Mod, Time);
+	    handle_msg(Msg, Parent, Name, StateName, StateData, Mod, Time, HibernateAfterTimeout);
 	_Msg ->
 	    Debug1 = sys:handle_debug(Debug, fun print_event/3,
 				      {Name, StateName}, {in, Msg}),
 	    handle_msg(Msg, Parent, Name, StateName, StateData,
-		       Mod, Time, Debug1)
+		       Mod, Time, HibernateAfterTimeout, Debug1)
     end.
 
 %%-----------------------------------------------------------------
 %% Callback functions for system messages handling.
 %%-----------------------------------------------------------------
-system_continue(Parent, Debug, [Name, StateName, StateData, Mod, Time]) ->
-    loop(Parent, Name, StateName, StateData, Mod, Time, Debug).
+system_continue(Parent, Debug, [Name, StateName, StateData, Mod, Time, HibernateAfterTimeout]) ->
+    loop(Parent, Name, StateName, StateData, Mod, Time, HibernateAfterTimeout, Debug).
 
 -spec system_terminate(term(), _, _, [term(),...]) -> no_return().
 
 system_terminate(Reason, _Parent, Debug,
-		 [Name, StateName, StateData, Mod, _Time]) ->
+		 [Name, StateName, StateData, Mod, _Time, _HibernateAfterTimeout]) ->
     terminate(Reason, Name, [], Mod, StateName, StateData, Debug).
 
-system_code_change([Name, StateName, StateData, Mod, Time],
+system_code_change([Name, StateName, StateData, Mod, Time, HibernateAfterTimeout],
 		   _Module, OldVsn, Extra) ->
     case catch Mod:code_change(OldVsn, StateName, StateData, Extra) of
 	{ok, NewStateName, NewStateData} ->
-	    {ok, [Name, NewStateName, NewStateData, Mod, Time]};
+	    {ok, [Name, NewStateName, NewStateData, Mod, Time, HibernateAfterTimeout]};
 	Else -> Else
     end.
 
-system_get_state([_Name, StateName, StateData, _Mod, _Time]) ->
+system_get_state([_Name, StateName, StateData, _Mod, _Time, _HibernateAfterTimeout]) ->
     {ok, {StateName, StateData}}.
 
-system_replace_state(StateFun, [Name, StateName, StateData, Mod, Time]) ->
+system_replace_state(StateFun, [Name, StateName, StateData, Mod, Time, HibernateAfterTimeout]) ->
     Result = {NStateName, NStateData} = StateFun({StateName, StateData}),
-    {ok, Result, [Name, NStateName, NStateData, Mod, Time]}.
+    {ok, Result, [Name, NStateName, NStateData, Mod, Time, HibernateAfterTimeout]}.
 
 %%-----------------------------------------------------------------
 %% Format debug messages.  Print them as the call-back module sees
@@ -467,19 +478,19 @@ print_event(Dev, return, {Name, StateName}) ->
     io:format(Dev, "*DBG* ~p switched to state ~w~n",
 	      [Name, StateName]).
 
-handle_msg(Msg, Parent, Name, StateName, StateData, Mod, _Time) -> %No debug here
+handle_msg(Msg, Parent, Name, StateName, StateData, Mod, _Time, HibernateAfterTimeout) -> %No debug here
     From = from(Msg),
     case catch dispatch(Msg, Mod, StateName, StateData) of
 	{next_state, NStateName, NStateData} ->	    
-	    loop(Parent, Name, NStateName, NStateData, Mod, infinity, []);
+	    loop(Parent, Name, NStateName, NStateData, Mod, infinity, HibernateAfterTimeout, []);
 	{next_state, NStateName, NStateData, Time1} ->
-	    loop(Parent, Name, NStateName, NStateData, Mod, Time1, []);
+	    loop(Parent, Name, NStateName, NStateData, Mod, Time1, HibernateAfterTimeout, []);
         {reply, Reply, NStateName, NStateData} when From =/= undefined ->
 	    reply(From, Reply),
-	    loop(Parent, Name, NStateName, NStateData, Mod, infinity, []);
+	    loop(Parent, Name, NStateName, NStateData, Mod, infinity, HibernateAfterTimeout, []);
         {reply, Reply, NStateName, NStateData, Time1} when From =/= undefined ->
 	    reply(From, Reply),
-	    loop(Parent, Name, NStateName, NStateData, Mod, Time1, []);
+	    loop(Parent, Name, NStateName, NStateData, Mod, Time1, HibernateAfterTimeout, []);
 	{stop, Reason, NStateData} ->
 	    terminate(Reason, Name, Msg, Mod, StateName, NStateData, []);
 	{stop, Reason, Reply, NStateData} when From =/= undefined ->
@@ -490,7 +501,7 @@ handle_msg(Msg, Parent, Name, StateName, StateData, Mod, _Time) -> %No debug her
         {'EXIT', {undef, [{Mod, handle_info, [_,_,_], _}|_]}} ->
             error_logger:warning_msg("** Undefined handle_info in ~p~n"
                                      "** Unhandled message: ~p~n", [Mod, Msg]),
-            loop(Parent, Name, StateName, StateData, Mod, infinity, []);
+            loop(Parent, Name, StateName, StateData, Mod, infinity, HibernateAfterTimeout, []);
 	{'EXIT', What} ->
 	    terminate(What, Name, Msg, Mod, StateName, StateData, []);
 	Reply ->
@@ -498,23 +509,23 @@ handle_msg(Msg, Parent, Name, StateName, StateData, Mod, _Time) -> %No debug her
 		      Name, Msg, Mod, StateName, StateData, [])
     end.
 
-handle_msg(Msg, Parent, Name, StateName, StateData, Mod, _Time, Debug) ->
+handle_msg(Msg, Parent, Name, StateName, StateData, Mod, _Time, HibernateAfterTimeout, Debug) ->
     From = from(Msg),
     case catch dispatch(Msg, Mod, StateName, StateData) of
 	{next_state, NStateName, NStateData} ->
 	    Debug1 = sys:handle_debug(Debug, fun print_event/3,
 				      {Name, NStateName}, return),
-	    loop(Parent, Name, NStateName, NStateData, Mod, infinity, Debug1);
+	    loop(Parent, Name, NStateName, NStateData, Mod, infinity, HibernateAfterTimeout, Debug1);
 	{next_state, NStateName, NStateData, Time1} ->
 	    Debug1 = sys:handle_debug(Debug, fun print_event/3,
 				      {Name, NStateName}, return),
-	    loop(Parent, Name, NStateName, NStateData, Mod, Time1, Debug1);
+	    loop(Parent, Name, NStateName, NStateData, Mod, Time1, HibernateAfterTimeout, Debug1);
         {reply, Reply, NStateName, NStateData} when From =/= undefined ->
 	    Debug1 = reply(Name, From, Reply, Debug, NStateName),
-	    loop(Parent, Name, NStateName, NStateData, Mod, infinity, Debug1);
+	    loop(Parent, Name, NStateName, NStateData, Mod, infinity, HibernateAfterTimeout, Debug1);
         {reply, Reply, NStateName, NStateData, Time1} when From =/= undefined ->
 	    Debug1 = reply(Name, From, Reply, Debug, NStateName),
-	    loop(Parent, Name, NStateName, NStateData, Mod, Time1, Debug1);
+	    loop(Parent, Name, NStateName, NStateData, Mod, Time1, HibernateAfterTimeout, Debug1);
 	{stop, Reason, NStateData} ->
 	    terminate(Reason, Name, Msg, Mod, StateName, NStateData, Debug);
 	{stop, Reason, Reply, NStateData} when From =/= undefined ->
@@ -645,7 +656,7 @@ get_msg(Msg) -> Msg.
 %% Status information
 %%-----------------------------------------------------------------
 format_status(Opt, StatusData) ->
-    [PDict, SysState, Parent, Debug, [Name, StateName, StateData, Mod, _Time]] =
+    [PDict, SysState, Parent, Debug, [Name, StateName, StateData, Mod, _Time, _HibernateAfterTimeout]] =
 	StatusData,
     Header = gen:format_status_header("Status for state machine",
                                       Name),
diff --git a/lib/stdlib/src/gen_server.erl b/lib/stdlib/src/gen_server.erl
index e628fec00f..ba0a7ae8e5 100644
--- a/lib/stdlib/src/gen_server.erl
+++ b/lib/stdlib/src/gen_server.erl
@@ -94,7 +94,7 @@
 	 cast/2, reply/2,
 	 abcast/2, abcast/3,
 	 multi_call/2, multi_call/3, multi_call/4,
-	 enter_loop/3, enter_loop/4, enter_loop/5, wake_hib/5]).
+	 enter_loop/3, enter_loop/4, enter_loop/5, wake_hib/6]).
 
 %% System exports
 -export([system_continue/3,
@@ -307,7 +307,8 @@ enter_loop(Mod, Options, State, ServerName, Timeout) ->
     Name = gen:get_proc_name(ServerName),
     Parent = gen:get_parent(),
     Debug = gen:debug_options(Name, Options),
-    loop(Parent, Name, State, Mod, Timeout, Debug).
+	HibernateAfterTimeout = gen:hibernate_after(Options),
+    loop(Parent, Name, State, Mod, Timeout, HibernateAfterTimeout, Debug).
 
 %%%========================================================================
 %%% Gen-callback functions
@@ -325,13 +326,14 @@ init_it(Starter, self, Name, Mod, Args, Options) ->
 init_it(Starter, Parent, Name0, Mod, Args, Options) ->
     Name = gen:name(Name0),
     Debug = gen:debug_options(Name, Options),
+	HibernateAfterTimeout = gen:hibernate_after(Options),
     case catch Mod:init(Args) of
 	{ok, State} ->
 	    proc_lib:init_ack(Starter, {ok, self()}), 	    
-	    loop(Parent, Name, State, Mod, infinity, Debug);
+	    loop(Parent, Name, State, Mod, infinity, HibernateAfterTimeout, Debug);
 	{ok, State, Timeout} ->
 	    proc_lib:init_ack(Starter, {ok, self()}), 	    
-	    loop(Parent, Name, State, Mod, Timeout, Debug);
+	    loop(Parent, Name, State, Mod, Timeout, HibernateAfterTimeout, Debug);
 	{stop, Reason} ->
 	    %% For consistency, we must make sure that the
 	    %% registered name (if any) is unregistered before
@@ -362,37 +364,46 @@ init_it(Starter, Parent, Name0, Mod, Args, Options) ->
 %%% ---------------------------------------------------
 %%% The MAIN loop.
 %%% ---------------------------------------------------
-loop(Parent, Name, State, Mod, hibernate, Debug) ->
-    proc_lib:hibernate(?MODULE,wake_hib,[Parent, Name, State, Mod, Debug]);
-loop(Parent, Name, State, Mod, Time, Debug) ->
+loop(Parent, Name, State, Mod, hibernate, HibernateAfterTimeout, Debug) ->
+    proc_lib:hibernate(?MODULE,wake_hib,[Parent, Name, State, Mod, HibernateAfterTimeout, Debug]);
+
+loop(Parent, Name, State, Mod, infinity, HibernateAfterTimeout, Debug) ->
+	receive
+		Msg ->
+			decode_msg(Msg, Parent, Name, State, Mod, infinity, HibernateAfterTimeout, Debug, false)
+	after HibernateAfterTimeout ->
+		loop(Parent, Name, State, Mod, hibernate, HibernateAfterTimeout, Debug)
+	end;
+
+loop(Parent, Name, State, Mod, Time, HibernateAfterTimeout, Debug) ->
     Msg = receive
 	      Input ->
 		    Input
 	  after Time ->
 		  timeout
 	  end,
-    decode_msg(Msg, Parent, Name, State, Mod, Time, Debug, false).
+    decode_msg(Msg, Parent, Name, State, Mod, Time, HibernateAfterTimeout, Debug, false).
 
-wake_hib(Parent, Name, State, Mod, Debug) ->
+wake_hib(Parent, Name, State, Mod, HibernateAfterTimeout, Debug) ->
     Msg = receive
 	      Input ->
 		  Input
 	  end,
-    decode_msg(Msg, Parent, Name, State, Mod, hibernate, Debug, true).
+    decode_msg(Msg, Parent, Name, State, Mod, hibernate, HibernateAfterTimeout, Debug, true).
 
-decode_msg(Msg, Parent, Name, State, Mod, Time, Debug, Hib) ->
+decode_msg(Msg, Parent, Name, State, Mod, Time, HibernateAfterTimeout, Debug, Hib) ->
     case Msg of
 	{system, From, Req} ->
 	    sys:handle_system_msg(Req, From, Parent, ?MODULE, Debug,
-				  [Name, State, Mod, Time], Hib);
+				  [Name, State, Mod, Time, HibernateAfterTimeout], Hib);
 	{'EXIT', Parent, Reason} ->
 	    terminate(Reason, Name, undefined, Msg, Mod, State, Debug);
 	_Msg when Debug =:= [] ->
-	    handle_msg(Msg, Parent, Name, State, Mod);
+	    handle_msg(Msg, Parent, Name, State, Mod, HibernateAfterTimeout);
 	_Msg ->
 	    Debug1 = sys:handle_debug(Debug, fun print_event/3,
 				      Name, {in, Msg}),
-	    handle_msg(Msg, Parent, Name, State, Mod, Debug1)
+	    handle_msg(Msg, Parent, Name, State, Mod, HibernateAfterTimeout, Debug1)
     end.
 
 %%% ---------------------------------------------------
@@ -659,65 +670,65 @@ try_terminate(Mod, Reason, State) ->
 %%% Message handling functions
 %%% ---------------------------------------------------
 
-handle_msg({'$gen_call', From, Msg}, Parent, Name, State, Mod) ->
+handle_msg({'$gen_call', From, Msg}, Parent, Name, State, Mod, HibernateAfterTimeout) ->
     Result = try_handle_call(Mod, Msg, From, State),
     case Result of
 	{ok, {reply, Reply, NState}} ->
 	    reply(From, Reply),
-	    loop(Parent, Name, NState, Mod, infinity, []);
+	    loop(Parent, Name, NState, Mod, infinity, HibernateAfterTimeout, []);
 	{ok, {reply, Reply, NState, Time1}} ->
 	    reply(From, Reply),
-	    loop(Parent, Name, NState, Mod, Time1, []);
+	    loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, []);
 	{ok, {noreply, NState}} ->
-	    loop(Parent, Name, NState, Mod, infinity, []);
+	    loop(Parent, Name, NState, Mod, infinity, HibernateAfterTimeout, []);
 	{ok, {noreply, NState, Time1}} ->
-	    loop(Parent, Name, NState, Mod, Time1, []);
+	    loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, []);
 	{ok, {stop, Reason, Reply, NState}} ->
 	    {'EXIT', R} = 
 		(catch terminate(Reason, Name, From, Msg, Mod, NState, [])),
 	    reply(From, Reply),
 	    exit(R);
-	Other -> handle_common_reply(Other, Parent, Name, From, Msg, Mod, State)
+	Other -> handle_common_reply(Other, Parent, Name, From, Msg, Mod, HibernateAfterTimeout, State)
     end;
-handle_msg(Msg, Parent, Name, State, Mod) ->
+handle_msg(Msg, Parent, Name, State, Mod, HibernateAfterTimeout) ->
     Reply = try_dispatch(Msg, Mod, State),
-    handle_common_reply(Reply, Parent, Name, undefined, Msg, Mod, State).
+    handle_common_reply(Reply, Parent, Name, undefined, Msg, Mod, HibernateAfterTimeout, State).
 
-handle_msg({'$gen_call', From, Msg}, Parent, Name, State, Mod, Debug) ->
+handle_msg({'$gen_call', From, Msg}, Parent, Name, State, Mod, HibernateAfterTimeout, Debug) ->
     Result = try_handle_call(Mod, Msg, From, State),
     case Result of
 	{ok, {reply, Reply, NState}} ->
 	    Debug1 = reply(Name, From, Reply, NState, Debug),
-	    loop(Parent, Name, NState, Mod, infinity, Debug1);
+	    loop(Parent, Name, NState, Mod, infinity, HibernateAfterTimeout, Debug1);
 	{ok, {reply, Reply, NState, Time1}} ->
 	    Debug1 = reply(Name, From, Reply, NState, Debug),
-	    loop(Parent, Name, NState, Mod, Time1, Debug1);
+	    loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, Debug1);
 	{ok, {noreply, NState}} ->
 	    Debug1 = sys:handle_debug(Debug, fun print_event/3, Name,
 				      {noreply, NState}),
-	    loop(Parent, Name, NState, Mod, infinity, Debug1);
+	    loop(Parent, Name, NState, Mod, infinity, HibernateAfterTimeout, Debug1);
 	{ok, {noreply, NState, Time1}} ->
 	    Debug1 = sys:handle_debug(Debug, fun print_event/3, Name,
 				      {noreply, NState}),
-	    loop(Parent, Name, NState, Mod, Time1, Debug1);
+	    loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, Debug1);
 	{ok, {stop, Reason, Reply, NState}} ->
 	    {'EXIT', R} = 
 		(catch terminate(Reason, Name, From, Msg, Mod, NState, Debug)),
 	    _ = reply(Name, From, Reply, NState, Debug),
 	    exit(R);
 	Other ->
-	    handle_common_reply(Other, Parent, Name, From, Msg, Mod, State, Debug)
+	    handle_common_reply(Other, Parent, Name, From, Msg, Mod, HibernateAfterTimeout, State, Debug)
     end;
-handle_msg(Msg, Parent, Name, State, Mod, Debug) ->
+handle_msg(Msg, Parent, Name, State, Mod, HibernateAfterTimeout, Debug) ->
     Reply = try_dispatch(Msg, Mod, State),
-    handle_common_reply(Reply, Parent, Name, undefined, Msg, Mod, State, Debug).
+    handle_common_reply(Reply, Parent, Name, undefined, Msg, Mod, HibernateAfterTimeout, State, Debug).
 
-handle_common_reply(Reply, Parent, Name, From, Msg, Mod, State) ->
+handle_common_reply(Reply, Parent, Name, From, Msg, Mod, HibernateAfterTimeout, State) ->
     case Reply of
 	{ok, {noreply, NState}} ->
-	    loop(Parent, Name, NState, Mod, infinity, []);
+	    loop(Parent, Name, NState, Mod, infinity, HibernateAfterTimeout, []);
 	{ok, {noreply, NState, Time1}} ->
-	    loop(Parent, Name, NState, Mod, Time1, []);
+	    loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, []);
 	{ok, {stop, Reason, NState}} ->
 	    terminate(Reason, Name, From, Msg, Mod, NState, []);
 	{'EXIT', ExitReason, ReportReason} ->
@@ -726,16 +737,16 @@ handle_common_reply(Reply, Parent, Name, From, Msg, Mod, State) ->
 	    terminate({bad_return_value, BadReply}, Name, From, Msg, Mod, State, [])
     end.
 
-handle_common_reply(Reply, Parent, Name, From, Msg, Mod, State, Debug) ->
+handle_common_reply(Reply, Parent, Name, From, Msg, Mod, HibernateAfterTimeout, State, Debug) ->
     case Reply of
 	{ok, {noreply, NState}} ->
 	    Debug1 = sys:handle_debug(Debug, fun print_event/3, Name,
 				      {noreply, NState}),
-	    loop(Parent, Name, NState, Mod, infinity, Debug1);
+	    loop(Parent, Name, NState, Mod, infinity, HibernateAfterTimeout, Debug1);
 	{ok, {noreply, NState, Time1}} ->
 	    Debug1 = sys:handle_debug(Debug, fun print_event/3, Name,
 				      {noreply, NState}),
-	    loop(Parent, Name, NState, Mod, Time1, Debug1);
+	    loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, Debug1);
 	{ok, {stop, Reason, NState}} ->
 	    terminate(Reason, Name, From, Msg, Mod, NState, Debug);
 	{'EXIT', ExitReason, ReportReason} ->
@@ -753,26 +764,26 @@ reply(Name, {To, Tag}, Reply, State, Debug) ->
 %%-----------------------------------------------------------------
 %% Callback functions for system messages handling.
 %%-----------------------------------------------------------------
-system_continue(Parent, Debug, [Name, State, Mod, Time]) ->
-    loop(Parent, Name, State, Mod, Time, Debug).
+system_continue(Parent, Debug, [Name, State, Mod, Time, HibernateAfterTimeout]) ->
+    loop(Parent, Name, State, Mod, Time, HibernateAfterTimeout, Debug).
 
 -spec system_terminate(_, _, _, [_]) -> no_return().
 
-system_terminate(Reason, _Parent, Debug, [Name, State, Mod, _Time]) ->
+system_terminate(Reason, _Parent, Debug, [Name, State, Mod, _Time, _HibernateAfterTimeout]) ->
     terminate(Reason, Name, undefined, [], Mod, State, Debug).
 
-system_code_change([Name, State, Mod, Time], _Module, OldVsn, Extra) ->
+system_code_change([Name, State, Mod, Time, HibernateAfterTimeout], _Module, OldVsn, Extra) ->
     case catch Mod:code_change(OldVsn, State, Extra) of
-	{ok, NewState} -> {ok, [Name, NewState, Mod, Time]};
+	{ok, NewState} -> {ok, [Name, NewState, Mod, Time, HibernateAfterTimeout]};
 	Else -> Else
     end.
 
-system_get_state([_Name, State, _Mod, _Time]) ->
+system_get_state([_Name, State, _Mod, _Time, _HibernateAfterTimeout]) ->
     {ok, State}.
 
-system_replace_state(StateFun, [Name, State, Mod, Time]) ->
+system_replace_state(StateFun, [Name, State, Mod, Time, HibernateAfterTimeout]) ->
     NState = StateFun(State),
-    {ok, NState, [Name, NState, Mod, Time]}.
+    {ok, NState, [Name, NState, Mod, Time, HibernateAfterTimeout]}.
 
 %%-----------------------------------------------------------------
 %% Format debug messages.  Print them as the call-back module sees
@@ -802,10 +813,10 @@ print_event(Dev, Event, Name) ->
 %%% Terminate the server.
 %%% ---------------------------------------------------
 
+
 -spec terminate(_, _, _, _, _, _, _) -> no_return().
 terminate(Reason, Name, From, Msg, Mod, State, Debug) ->
     terminate(Reason, Reason, Name, From, Msg, Mod, State, Debug).
-
 -spec terminate(_, _, _, _, _, _, _, _) -> no_return().
 terminate(ExitReason, ReportReason, Name, From, Msg, Mod, State, Debug) ->
     Reply = try_terminate(Mod, ExitReason, State),
@@ -851,7 +862,7 @@ error_info(Reason, Name, From, Msg, State, Debug) ->
 		end;
 	    _ ->
 		Reason
-	end,
+	end,    
     {ClientFmt, ClientArgs} = client_stacktrace(From),
     format("** Generic server ~p terminating \n"
            "** Last message in was ~p~n"
@@ -860,7 +871,6 @@ error_info(Reason, Name, From, Msg, State, Debug) ->
 	   [Name, Msg, State, Reason1] ++ ClientArgs),
     sys:print_log(Debug),
     ok.
-
 client_stacktrace(undefined) ->
     {"", []};
 client_stacktrace({From, _Tag}) ->
@@ -885,7 +895,7 @@ client_stacktrace(From) when is_pid(From) ->
 %% Status information
 %%-----------------------------------------------------------------
 format_status(Opt, StatusData) ->
-    [PDict, SysState, Parent, Debug, [Name, State, Mod, _Time]] = StatusData,
+    [PDict, SysState, Parent, Debug, [Name, State, Mod, _Time, _HibernateAfterTimeout]] = StatusData,
     Header = gen:format_status_header("Status for generic server", Name),
     Log = sys:get_debug(log, Debug, []),
     Specfic = case format_status(Opt, Mod, PDict, State) of
diff --git a/lib/stdlib/src/gen_statem.erl b/lib/stdlib/src/gen_statem.erl
index 6f566b8beb..86109f04b4 100644
--- a/lib/stdlib/src/gen_statem.erl
+++ b/lib/stdlib/src/gen_statem.erl
@@ -369,9 +369,12 @@ event_type(Type) ->
 	 Dbgs ::
 	   ['trace' | 'log' | 'statistics' | 'debug'
 	    | {'logfile', string()}]}.
+-type hibernate_after_opt() ::
+	{'hibernate_after', HibernateAfterTimeout :: timeout()}.
 -type start_opt() ::
 	debug_opt()
       | {'timeout', Time :: timeout()}
+	  | hibernate_after_opt()
       | {'spawn_opt', [proc_lib:spawn_option()]}.
 -type start_ret() ::  {'ok', pid()} | 'ignore' | {'error', term()}.
 
@@ -544,14 +547,14 @@ reply({To,Tag}, Reply) when is_pid(To) ->
 %% started by proc_lib into a state machine using
 %% the same arguments as you would have returned from init/1
 -spec enter_loop(
-	Module :: module(), Opts :: [debug_opt()],
+	Module :: module(), Opts :: [debug_opt() | hibernate_after_opt()],
 	State :: state(), Data :: data()) ->
 			no_return().
 enter_loop(Module, Opts, State, Data) ->
     enter_loop(Module, Opts, State, Data, self()).
 %%
 -spec enter_loop(
-	Module :: module(), Opts :: [debug_opt()],
+	Module :: module(), Opts :: [debug_opt() | hibernate_after_opt()],
 	State :: state(), Data :: data(),
 	Server_or_Actions ::
 	  server_name() | pid() | [action()]) ->
@@ -565,7 +568,7 @@ enter_loop(Module, Opts, State, Data, Server_or_Actions) ->
     end.
 %%
 -spec enter_loop(
-	Module :: module(), Opts :: [debug_opt()],
+	Module :: module(), Opts :: [debug_opt() | hibernate_after_opt()],
 	State :: state(), Data :: data(),
 	Server :: server_name() | pid(),
 	Actions :: [action()] | action()) ->
@@ -605,7 +608,8 @@ enter(Module, Opts, State, Data, Server, Actions, Parent) ->
     %% The values should already have been type checked
     Name = gen:get_proc_name(Server),
     Debug = gen:debug_options(Name, Opts),
-    Events = [],
+	HibernateAfterTimeout = gen:hibernate_after(Opts),
+	Events = [],
     P = [],
     Event = {internal,init_state},
     %% We enforce {postpone,false} to ensure that
@@ -648,6 +652,7 @@ enter(Module, Opts, State, Data, Server, Actions, Parent) ->
       timer_refs => TimerRefs,
       timer_types => TimerTypes,
       hibernate => Hibernate,
+	  hibernate_after => HibernateAfterTimeout,
       cancel_timers => CancelTimers
      },
     NewDebug = sys_debug(Debug, S, State, {enter,Event,State}),
@@ -854,7 +859,7 @@ loop_hibernate(Parent, Debug, S) ->
        {wakeup_from_hibernate,3}}).
 
 %% Entry point for wakeup_from_hibernate/3
-loop_receive(Parent, Debug, S) ->
+loop_receive(Parent, Debug, #{hibernate_after := HibernateAfterTimeout} = S) ->
     receive
 	Msg ->
 	    case Msg of
@@ -956,6 +961,9 @@ loop_receive(Parent, Debug, S) ->
 		    loop_receive_result(
 		      Parent, Debug, S, Hibernate, Event)
 	    end
+    after
+	    HibernateAfterTimeout ->
+		    loop_hibernate(Parent, Debug, S)
     end.
 
 loop_receive_result(
diff --git a/lib/stdlib/test/dummy_h.erl b/lib/stdlib/test/dummy_h.erl
index 45ccfee240..7a9eb11f98 100644
--- a/lib/stdlib/test/dummy_h.erl
+++ b/lib/stdlib/test/dummy_h.erl
@@ -43,6 +43,9 @@ handle_event(hibernate, _State) ->
    {ok,[],hibernate};
 handle_event(wakeup, _State) ->
     {ok,[]};
+handle_event({From, handle_event}, _State) ->
+    From ! handled_event,
+    {ok,[]};
 handle_event(Event, Parent) ->
     Parent ! {dummy_h, Event},
     {ok, Parent}.
@@ -75,6 +78,9 @@ handle_info(wake, _State) ->
     {ok, []};
 handle_info(gnurf, _State) ->
     {ok, []};
+handle_info({From, handle_info}, _State) ->
+    From ! handled_info,
+    {ok, []};
 handle_info(Info, Parent) ->
     Parent ! {dummy_h, Info},
     {ok, Parent}.
diff --git a/lib/stdlib/test/gen_event_SUITE.erl b/lib/stdlib/test/gen_event_SUITE.erl
index 749920f843..880b10117c 100644
--- a/lib/stdlib/test/gen_event_SUITE.erl
+++ b/lib/stdlib/test/gen_event_SUITE.erl
@@ -26,7 +26,7 @@
          end_per_testcase/2]).
 -export([start/1, add_handler/1, add_sup_handler/1,
 	 delete_handler/1, swap_handler/1, swap_sup_handler/1,
-	 notify/1, sync_notify/1, call/1, info/1, hibernate/1,
+	 notify/1, sync_notify/1, call/1, info/1, hibernate/1, auto_hibernate/1,
 	 call_format_status/1, call_format_status_anon/1,
          error_format_status/1, get_state/1, replace_state/1,
          start_opt/1,
@@ -37,7 +37,7 @@
 suite() -> [{ct_hooks,[ts_install_cth]}].
 
 all() ->
-    [start, {group, test_all}, hibernate,
+    [start, {group, test_all}, hibernate, auto_hibernate,
      call_format_status, call_format_status_anon, error_format_status,
      get_state, replace_state,
      start_opt, {group, undef_callbacks}, undef_in_terminate].
@@ -306,6 +306,48 @@ hibernate(Config) when is_list(Config) ->
 
     ok.
 
+auto_hibernate(Config) when is_list(Config) ->
+    HibernateAfterTimeout = 100,
+    State = {auto_hibernate_state},
+    {ok,Pid} = gen_event:start({local, auto_hibernate_handler}, [{hibernate_after, HibernateAfterTimeout}]),
+    %% After init test
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    ok = gen_event:add_handler(auto_hibernate_handler, dummy_h, [State]),
+    %% Get state test
+    [{dummy_h,false,State}] = sys:get_state(Pid),
+    is_in_erlang_hibernate(Pid),
+    %% Call test
+    {ok, hejhopp} = gen_event:call(auto_hibernate_handler, dummy_h, hejsan),
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    %% Event test
+    ok = gen_event:notify(auto_hibernate_handler, {self(), handle_event}),
+    receive
+        handled_event ->
+            ok
+    after 1000 ->
+        ct:fail(event)
+    end,
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    %% Info test
+    Pid ! {self(), handle_info},
+    receive
+        handled_info ->
+            ok
+    after 1000 ->
+        ct:fail(info)
+    end,
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    ok = gen_event:stop(auto_hibernate_handler),
+    ok.
+
 is_in_erlang_hibernate(Pid) ->
     receive after 1 -> ok end,
     is_in_erlang_hibernate_1(200, Pid).
diff --git a/lib/stdlib/test/gen_fsm_SUITE.erl b/lib/stdlib/test/gen_fsm_SUITE.erl
index 7f98526d35..86cf58566b 100644
--- a/lib/stdlib/test/gen_fsm_SUITE.erl
+++ b/lib/stdlib/test/gen_fsm_SUITE.erl
@@ -44,7 +44,7 @@
 
 -export([undef_in_handle_info/1, undef_in_terminate/1]).
 
--export([hibernate/1,hiber_idle/3,hiber_wakeup/3,hiber_idle/2,hiber_wakeup/2]).
+-export([hibernate/1,auto_hibernate/1,hiber_idle/3,hiber_wakeup/3,hiber_idle/2,hiber_wakeup/2]).
 
 -export([enter_loop/1]).
 
@@ -68,7 +68,7 @@ suite() -> [{ct_hooks,[ts_install_cth]}].
 
 all() ->
     [{group, start}, {group, abnormal}, shutdown,
-     {group, sys}, hibernate, enter_loop, {group, undef_callbacks},
+     {group, sys}, hibernate, auto_hibernate, enter_loop, {group, undef_callbacks},
      undef_in_handle_info, undef_in_terminate].
 
 groups() ->
@@ -700,6 +700,43 @@ hibernate(Config) when is_list(Config) ->
     process_flag(trap_exit, OldFl),
     ok.
 
+%% Auto hibernation
+auto_hibernate(Config) when is_list(Config) ->
+    OldFl = process_flag(trap_exit, true),
+    HibernateAfterTimeout = 100,
+    State = {auto_hibernate_state},
+    {ok, Pid} = gen_fsm:start_link({local, my_test_name_auto_hibernate}, ?MODULE, {state_data, State}, [{hibernate_after, HibernateAfterTimeout}]),
+    %% After init test
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    %% Get state test
+    {_, State} = sys:get_state(my_test_name_auto_hibernate),
+    is_in_erlang_hibernate(Pid),
+    %% Sync send event test
+    'alive!' = gen_fsm:sync_send_event(Pid,'alive?'),
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    %% Send event test
+    ok = gen_fsm:send_all_state_event(Pid,{'alive?', self()}),
+    wfor(yes),
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    %% Info test
+    Pid ! {self(), handle_info},
+    wfor({Pid, handled_info}),
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    stop_it(Pid),
+    receive
+        {'EXIT',Pid,normal} -> ok
+    end,
+    process_flag(trap_exit, OldFl),
+    ok.
+
 is_in_erlang_hibernate(Pid) ->
     receive after 1 -> ok end,
     is_in_erlang_hibernate_1(200, Pid).
@@ -1151,6 +1188,8 @@ idle(badreturn, _From, _Data) ->
 idle({timeout,Time}, From, _Data) ->
     gen_fsm:send_event_after(Time, {timeout,Time}),
     {next_state, timeout, From};
+idle('alive?', _From, Data) ->
+    {reply, 'alive!', idle, Data};
 idle(_, _From, Data) ->
     {reply, 'eh?', idle, Data}.
 
@@ -1226,6 +1265,9 @@ handle_info(hibernate_later, _SName, _State) ->
 handle_info({call_undef_fun, {Mod, Fun}}, State, Data) ->
     Mod:Fun(),
     {next_state, State, Data};
+handle_info({From, handle_info}, SName, State) ->
+    From ! {self(), handled_info},
+    {next_state, SName, State};
 handle_info(Info, _State, Data) ->
     {stop, {unexpected,Info}, Data}.
 
diff --git a/lib/stdlib/test/gen_server_SUITE.erl b/lib/stdlib/test/gen_server_SUITE.erl
index 6f72034b09..7e3c71715e 100644
--- a/lib/stdlib/test/gen_server_SUITE.erl
+++ b/lib/stdlib/test/gen_server_SUITE.erl
@@ -32,7 +32,7 @@
 	 call_remote_n1/1, call_remote_n2/1, call_remote_n3/1, spec_init/1,
 	 spec_init_local_registered_parent/1, 
 	 spec_init_global_registered_parent/1,
-	 otp_5854/1, hibernate/1, otp_7669/1, call_format_status/1,
+	 otp_5854/1, hibernate/1, auto_hibernate/1, otp_7669/1, call_format_status/1,
 	 error_format_status/1, terminate_crash_format/1,
 	 get_state/1, replace_state/1, call_with_huge_message_queue/1,
 	 undef_handle_call/1, undef_handle_cast/1, undef_handle_info/1,
@@ -65,7 +65,7 @@ all() ->
      call_remote3, call_remote_n1, call_remote_n2,
      call_remote_n3, spec_init,
      spec_init_local_registered_parent,
-     spec_init_global_registered_parent, otp_5854, hibernate,
+     spec_init_global_registered_parent, otp_5854, hibernate, auto_hibernate,
      otp_7669,
      call_format_status, error_format_status, terminate_crash_format,
      get_state, replace_state,
@@ -730,6 +730,58 @@ hibernate(Config) when is_list(Config) ->
     process_flag(trap_exit, OldFl),
     ok.
 
+auto_hibernate(Config) when is_list(Config) ->
+    OldFl = process_flag(trap_exit, true),
+    HibernateAfterTimeout = 100,
+    State = {auto_hibernate_state},
+    {ok, Pid} =
+        gen_server:start_link({local, my_test_name_auto_hibernate},
+            gen_server_SUITE, {state,State}, [{hibernate_after, HibernateAfterTimeout}]),
+    %% After init test
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    %% Get state test
+    State = sys:get_state(my_test_name_auto_hibernate),
+    is_in_erlang_hibernate(Pid),
+    %% Call test
+    ok = gen_server:call(my_test_name_auto_hibernate, started_p),
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    %% Cast test
+    ok = gen_server:cast(my_test_name_auto_hibernate, {self(),handle_cast}),
+    receive
+        {Pid, handled_cast} ->
+            ok
+    after 1000 ->
+        ct:fail(cast)
+    end,
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    %% Info test
+    Pid ! {self(),handle_info},
+    receive
+        {Pid, handled_info} ->
+            ok
+    after 1000 ->
+        ct:fail(info)
+    end,
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+
+    ok = gen_server:call(my_test_name_auto_hibernate, stop),
+    receive
+        {'EXIT', Pid, stopped} ->
+            ok
+    after 5000 ->
+        ct:fail(gen_server_did_not_die)
+    end,
+    process_flag(trap_exit, OldFl),
+    ok.
+
 is_in_erlang_hibernate(Pid) ->
     receive after 1 -> ok end,
     is_in_erlang_hibernate_1(200, Pid).
@@ -747,6 +799,23 @@ is_in_erlang_hibernate_1(N, Pid) ->
 	    is_in_erlang_hibernate_1(N-1, Pid)
     end.
 
+is_not_in_erlang_hibernate(Pid) ->
+    receive after 1 -> ok end,
+    is_not_in_erlang_hibernate_1(200, Pid).
+
+is_not_in_erlang_hibernate_1(0, Pid) ->
+    io:format("~p\n", [erlang:process_info(Pid, current_function)]),
+    ct:fail(not_in_erlang_hibernate_3);
+is_not_in_erlang_hibernate_1(N, Pid) ->
+    {current_function,MFA} = erlang:process_info(Pid, current_function),
+    case MFA of
+        {erlang,hibernate,3} ->
+            receive after 10 -> ok end,
+            is_not_in_erlang_hibernate_1(N-1, Pid);
+        _ ->
+            ok
+    end.
+
 %% --------------------------------------
 %% Test gen_server:abcast and handle_cast.
 %% Test all different return values from
diff --git a/lib/stdlib/test/gen_statem_SUITE.erl b/lib/stdlib/test/gen_statem_SUITE.erl
index 05934b3953..5b9daecfd3 100644
--- a/lib/stdlib/test/gen_statem_SUITE.erl
+++ b/lib/stdlib/test/gen_statem_SUITE.erl
@@ -40,7 +40,7 @@ all() ->
      shutdown, stop_and_reply, state_enter, event_order,
      state_timeout, event_types, generic_timers, code_change,
      {group, sys},
-     hibernate, enter_loop, {group, undef_callbacks},
+     hibernate, auto_hibernate, enter_loop, {group, undef_callbacks},
      undef_in_terminate].
 
 groups() ->
@@ -1284,6 +1284,84 @@ hibernate(Config) ->
     end,
     ok = verify_empty_msgq().
 
+%% Auto-hibernation timeout
+auto_hibernate(Config) ->
+    OldFl = process_flag(trap_exit, true),
+    HibernateAfterTimeout = 100,
+
+    {ok,Pid} =
+        gen_statem:start_link(
+            ?MODULE, start_arg(Config, []), [{hibernate_after, HibernateAfterTimeout}]),
+    %% After init test
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    %% After info test
+    Pid ! {hping, self()},
+    receive
+        {Pid, hpong} ->
+            ok
+    after 1000 ->
+        ct:fail(info)
+    end,
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    %% After cast test
+    ok = gen_statem:cast(Pid, {hping, self()}),
+    receive
+        {Pid, hpong} ->
+            ok
+    after 1000 ->
+        ct:fail(cast)
+    end,
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    %% After call test
+    hpong = gen_statem:call(Pid, hping),
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    %% Timer test 1
+    TimerTimeout1 = 50,
+    ok = gen_statem:call(Pid, {arm_htimer, self(), TimerTimeout1}),
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(TimerTimeout1),
+    is_not_in_erlang_hibernate(Pid),
+    receive
+        {Pid, htimer_armed} ->
+            ok
+    after 1000 ->
+        ct:fail(timer1)
+    end,
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    %% Timer test 2
+    TimerTimeout2 = 150,
+    ok = gen_statem:call(Pid, {arm_htimer, self(), TimerTimeout2}),
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    receive
+        {Pid, htimer_armed} ->
+            ok
+    after 1000 ->
+        ct:fail(timer2)
+    end,
+    is_not_in_erlang_hibernate(Pid),
+    timer:sleep(HibernateAfterTimeout),
+    is_in_erlang_hibernate(Pid),
+    stop_it(Pid),
+    process_flag(trap_exit, OldFl),
+    receive
+        {'EXIT',Pid,normal} -> ok
+    after 5000 ->
+        ct:fail(gen_statem_did_not_die)
+    end,
+    ok = verify_empty_msgq().
+
 is_in_erlang_hibernate(Pid) ->
     receive after 1 -> ok end,
     is_in_erlang_hibernate_1(200, Pid).
@@ -1704,6 +1782,19 @@ terminate(_Reason, _State, _Data) ->
 
 %% State functions
 
+idle(info, {hping,Pid}, _Data) ->
+    Pid ! {self(), hpong},
+    keep_state_and_data;
+idle(cast, {hping,Pid}, Data) ->
+    Pid ! {self(), hpong},
+    {keep_state, Data};
+idle({call, From}, hping, _Data) ->
+    {keep_state_and_data, [{reply, From, hpong}]};
+idle({call, From}, {arm_htimer, Pid, Timeout}, _Data) ->
+    {keep_state_and_data, [{reply, From, ok}, {timeout, Timeout, {arm_htimer, Pid}}]};
+idle(timeout, {arm_htimer, Pid}, _Data) ->
+    Pid ! {self(), htimer_armed},
+    keep_state_and_data;
 idle(cast, {connect,Pid}, Data) ->
     Pid ! accept,
     {next_state,wfor_conf,Data,infinity}; % NoOp timeout just to test API