Remove module 'overload' from SASL

The reason is that the module is not used, and that we se no obvious
use case for it.

5 files changed, 4 insertions, 241 deletions

diff --git a/lib/sasl/src/Makefile b/lib/sasl/src/Makefile
index 7ff6a03a50..92d4818f2e 100644
--- a/lib/sasl/src/Makefile
+++ b/lib/sasl/src/Makefile
@@ -36,7 +36,7 @@ RELSYSDIR = $(RELEASE_PATH)/lib/sasl-$(VSN)
 # ----------------------------------------------------
 MODULES= alarm_handler sasl sasl_report \
 	sasl_report_file_h sasl_report_tty_h format_lib_supp \
-	misc_supp overload rb rb_format_supp release_handler \
+	misc_supp rb rb_format_supp release_handler \
 	release_handler_1 si si_sasl_supp systools \
 	systools_make systools_rc systools_relup systools_lib \
 	erlsrv
diff --git a/lib/sasl/src/misc_supp.erl b/lib/sasl/src/misc_supp.erl
index 42de7eedec..39656f6e65 100644
--- a/lib/sasl/src/misc_supp.erl
+++ b/lib/sasl/src/misc_supp.erl
@@ -27,7 +27,7 @@
 %%% 2) Very generic functions such as, multi_map, is_string...
 %%%
 %%% This module is a part of the BOS.  (format_pdict is called from
-%%% init, memsup, disksup, overload (but not the fileserver since it
+%%% init, memsup, disksup (but not the fileserver since it
 %%% formats its pdict its own way).)
 %%%---------------------------------------------------------------------
 
diff --git a/lib/sasl/src/overload.erl b/lib/sasl/src/overload.erl
deleted file mode 100644
index bc8ab7d5e4..0000000000
--- a/lib/sasl/src/overload.erl
+++ /dev/null
@@ -1,233 +0,0 @@
-%%
-%% %CopyrightBegin%
-%%
-%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
-%%
-%% Licensed under the Apache License, Version 2.0 (the "License");
-%% you may not use this file except in compliance with the License.
-%% You may obtain a copy of the License at
-%%
-%%     http://www.apache.org/licenses/LICENSE-2.0
-%%
-%% Unless required by applicable law or agreed to in writing, software
-%% distributed under the License is distributed on an "AS IS" BASIS,
-%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-%% See the License for the specific language governing permissions and
-%% limitations under the License.
-%%
-%% %CopyrightEnd%
-%%
--module(overload). 
-
--deprecated(module).
-
--export([start_link/0, request/0, set_config_data/2,
-	 get_overload_info/0]).
-
--export([init/1, handle_call/3, handle_info/2, terminate/2,
-	 format_status/2]).
-
-%%%-----------------------------------------------------------------
-%%% This is a rewrite of overload from BS.3, by Peter Högfeldt.
-%%%
-%%% DESCRIPTION
-%%%
-%%% This module implements a server process that keeps record of the
-%%% intensity of calls of the request/0 function, and answers accept or
-%%% reject depending on if the current average intensity is not greater 
-%%% than a specified maximum intensity.
-%%%
-%%% The intensity i is calculated according to the formula:
-%%%    i(n) = exp(-K*(T(n) - T(n-1)))*i(n-1) + Kappa
-%%% where i(n) is the intensity at event n, Kappa is a constant, and
-%%% T(n) is the time at event n.
-%%%
-%%% The constant Kappa can be thought of as 1 / T, where T is the time 
-%%% constant. Kappa is externally referred to as Weight.
-%%%  
-%%% We keep track of two intensities: the total call intensity and the 
-%%% intensity of accepted calls.
-%%%-----------------------------------------------------------------
-%%% TODO
-%%%
-%%% 3. Hysteresis.
-%%%
-%%%-----------------------------------------------------------------
-
--record(state, {total = 0, accept = 0, max, prev_t = get_now(),
-		kappa, call_counts = {0, 0}, alarm = clear}).
-
--define(clear_timeout, 30000).
-  
-start_link() ->
-    gen_server:start_link({local, overload}, overload, [], []).
-
-init([]) ->
-    process_flag(priority, high),
-    MaxIntensity = fetch_config_data(overload_max_intensity),
-    Kappa = fetch_config_data(overload_weight),
-    {ok, #state{max = MaxIntensity, kappa = Kappa}}.
-  
-%%-----------------------------------------------------------------
-%% Func: request/0
-%% Purpose: This is a request to proceed, e.g. a request to
-%%          establish a call.
-%% Returns: accept | reject
-%%-----------------------------------------------------------------
-request() -> call(request).
-  
-%%-----------------------------------------------------------------
-%% Func: set_config_data/2
-%% Purpose: Set configuration data, and reset intensities.
-%% Arguments: MaxIntensity (real > 0), Weight (real > 0).
-%% Returns: ok | {error, What}
-%% This function is for debugging purposes and is therefore not
-%% documented at all.
-%%-----------------------------------------------------------------
-set_config_data(MaxIntensity, Weight) ->
-    call({set_config_data, MaxIntensity, Weight}).
-%%-----------------------------------------------------------------
-%% Func: get_overload_info/0
-%% Returns: A list of tagged items: TotalIntensity, AcceptIntensity,
-%%          MaxIntensity, Weight, TotalRequests, AcceptedRequests.
-%%-----------------------------------------------------------------
-get_overload_info() -> call(get_overload_info).
-
-%%-----------------------------------------------------------------
-%% call(Request) -> Term
-%%-----------------------------------------------------------------
-call(Req) ->
-    gen_server:call(overload, Req, infinity).
-
-%%%-----------------------------------------------------------------
-%%% Callback functions from gen_server
-%%%-----------------------------------------------------------------
-handle_call(request, _From, State) ->
-    #state{total = TI, accept = AI, kappa = Kappa, prev_t = PrevT,
-	  alarm = Alarm} = State,
-    {TR, AR} = State#state.call_counts,
-    T = get_now(),
-    CurI = new_intensity(AI, T, PrevT, Kappa),
-    NewTI  = new_intensity(TI, T, PrevT, Kappa) + Kappa,
-    if 
-	CurI =< State#state.max ->
-	    %% Hysteresis: If alarm is set, and current intensity has
-	    %% fallen below 75% of max intensity, clear alarm.
-	    NewAlarm = if
-			   CurI =< 0.75*State#state.max ->
-			       clear_alarm(Alarm);
-			   true ->
-			       Alarm
-		       end,
-	    {reply, accept, State#state{call_counts = {TR+1, AR+1}, 
-					prev_t = T, total = NewTI, 
-					accept = CurI + Kappa, 
-				        alarm = NewAlarm},
-	     ?clear_timeout};
-        true ->
-	    %% Set alarm if not already set.
-	    NewAlarm = set_alarm(Alarm),
-	    {reply, reject,
-	     State#state{call_counts = {TR+1, AR}, prev_t = T,
-			 total = NewTI, accept = CurI,
-				       alarm = NewAlarm},
-	    ?clear_timeout}
-    end;
-handle_call({set_config_data, MaxIntensity, Weight}, _From, _State) ->
-    {reply, ok, #state{max = MaxIntensity, kappa = Weight},
-     ?clear_timeout};
-handle_call(get_overload_info, _From, State) ->
-    #state{max = MI, total = TI, accept = AI, kappa = Kappa,
-	   prev_t = PrevT, call_counts = {TR, AR}} = State,
-    T = get_now(),
-    CurI = new_intensity(AI, T, PrevT, Kappa),
-    NewTI  = new_intensity(TI, T, PrevT, Kappa),
-    Reply = [{total_intensity, NewTI}, {accept_intensity, CurI}, 
-	     {max_intensity, MI}, {weight, Kappa},
-	     {total_requests, TR}, {accepted_requests, AR}],
-    {reply, Reply, State#state{total = NewTI, accept = CurI},
-     ?clear_timeout}.
-
-handle_info(timeout, State) ->
-    #state{total = TI, accept = AI, kappa = Kappa, prev_t = PrevT,
-	  alarm = Alarm} = State,
-    T = get_now(),
-    CurI = new_intensity(AI, T, PrevT, Kappa),
-    NewTI  = new_intensity(TI, T, PrevT, Kappa),
-    if 
-	CurI < 0.75* State#state.max ->
-	    NewAlarm = clear_alarm(Alarm),
-	    {noreply, State#state{total = NewTI, accept = CurI, 
-				  alarm = NewAlarm}};
-	    
-	true ->
-	    {noreply, State#state{total = NewTI, accept = CurI},
-	     ?clear_timeout}
-    end;
-
-handle_info(_, State) ->
-    {noreply, State, ?clear_timeout}.
-
-terminate(_Reason, _State) ->
-    ok.
-
-%%-----------------------------------------------------------------
-%% Internal functions
-%%-----------------------------------------------------------------
-fetch_config_data(Tag) ->
-    case application:get_env(sasl, Tag) of
-	{ok, Value} -> Value;
-	_ -> fetch_default_data(Tag)
-    end.
-  
-fetch_default_data(overload_max_intensity) -> 0.8;
-fetch_default_data(overload_weight) -> 0.1.
-
-set_alarm(clear) ->
-    alarm_handler:set_alarm({overload, []}),
-    set;
-set_alarm(Alarm) ->
-    Alarm.
-
-clear_alarm(set) ->
-    alarm_handler:clear_alarm(overload),
-    clear;
-clear_alarm(Alarm) ->
-    Alarm.
-
-%%-----------------------------------------------------------------
-%% The catch protects against floating-point exception.
-%%
-new_intensity(I, T, PrevT, K) ->
-    Diff = sub(T, PrevT)/1000,
-    case catch (I*math:exp(-K*Diff)) of
-	{'EXIT', _} ->				% Assume zero.
-	    0.0;
-	Res ->
-	    Res
-    end.
-
-%% Mask equal to 2^27 - 1, used below.
--define(mask27, 16#7ffffff).
-
-%% Returns number of milliseconds in the range [0, 2^27 - 1]. Must have
-%% this since statistics(wall_clock) wraps. Having 2^27 -1 as the max
-%% assures that we always get non-negative integers. 2^27 milliseconds 
-%% are approx. 37.28 hours.
-get_now() -> 
-    element(1, statistics(wall_clock)) band ?mask27.
-
-%% Returns (X - Y) mod 2^27 (which is in the range [0, 2^27 - 1]).
-sub(X, Y) ->
-    (X + (bnot Y) + 1) band ?mask27.
-
-format_status(Opt, [PDict, #state{max = MI, total = TI, accept = AI,
-				  kappa = K,
-				  call_counts = {TR, AR}}]) ->
-    [{data, [{"Total Intensity", TI},
-	     {"Accept Intensity", AI}, 
-	     {"Max Intensity", MI},
-	     {"Weight", K},
-	     {"Total requests", TR},
-	     {"Accepted requests", AR}]} |
-     misc_supp:format_pdict(Opt, PDict, [])].     
diff --git a/lib/sasl/src/sasl.app.src b/lib/sasl/src/sasl.app.src
index 507e2dc229..16e8e44ba2 100644
--- a/lib/sasl/src/sasl.app.src
+++ b/lib/sasl/src/sasl.app.src
@@ -24,7 +24,6 @@
 	       alarm_handler, 
                format_lib_supp, 
                misc_supp, 
-               overload, 
                rb, 
                rb_format_supp, 
 	       release_handler, 
@@ -41,7 +40,7 @@
 	       systools_relup, 
 	       systools_lib
 	      ]},
-    {registered, [sasl_sup, alarm_handler, overload, release_handler]},
+    {registered, [sasl_sup, alarm_handler, release_handler]},
     {applications, [kernel, stdlib]},
     {env, [{sasl_error_logger, tty},
            {errlog_type, all}]},
diff --git a/lib/sasl/src/sasl.erl b/lib/sasl/src/sasl.erl
index fc49fc2465..0fb85682c6 100644
--- a/lib/sasl/src/sasl.erl
+++ b/lib/sasl/src/sasl.erl
@@ -170,7 +170,4 @@ init(safe) ->
     AlarmH = {alarm_handler,
 	      {alarm_handler, start_link, []},
 	      permanent, 2000, worker, dynamic},	      
-    Overload = {overload,
-		{overload, start_link, []},
-		permanent, 2000, worker, [overload]},	      
-    {ok, {SupFlags, [AlarmH, Overload]}}.
+    {ok, {SupFlags, [AlarmH]}}.