Merge branch 'cf/simple_one_for_one_shutdown'

* cf/simple_one_for_one_shutdown:
  Explain how dynamic child processes are stopped
  Stack errors when dynamic children are stopped
  Explicitly kill dynamic children in supervisors

Conflicts:
	lib/stdlib/doc/src/supervisor.xml

OTP-9647

1 files changed, 116 insertions, 5 deletions

diff --git a/lib/stdlib/src/supervisor.erl b/lib/stdlib/src/supervisor.erl
index 051dca462b..f20ea18fd0 100644
--- a/lib/stdlib/src/supervisor.erl
+++ b/lib/stdlib/src/supervisor.erl
@@ -515,9 +515,12 @@ handle_info(Msg, State) ->
 %%
 -spec terminate(term(), state()) -> 'ok'.
 
+terminate(_Reason, #state{children=[Child]} = State) when ?is_simple(State) ->
+    terminate_dynamic_children(Child, dynamics_db(Child#child.restart_type,
+                                                  State#state.dynamics),
+                               State#state.name);
 terminate(_Reason, State) ->
-    terminate_children(State#state.children, State#state.name),
-    ok.
+    terminate_children(State#state.children, State#state.name).
 
 %%
 %% Change code for the supervisor.
@@ -830,8 +833,109 @@ monitor_child(Pid) ->
 	    %% that will be handled in shutdown/2. 
 	    ok   
     end.
-    
-   
+
+
+%%-----------------------------------------------------------------
+%% Func: terminate_dynamic_children/3
+%% Args: Child    = child_rec()
+%%       Dynamics = ?DICT() | ?SET()
+%%       SupName  = {local, atom()} | {global, atom()} | {pid(),Mod}
+%% Returns: ok
+%%
+%%
+%% Shutdown all dynamic children. This happens when the supervisor is
+%% stopped. Because the supervisor can have millions of dynamic children, we
+%% can have an significative overhead here.
+%%-----------------------------------------------------------------
+terminate_dynamic_children(Child, Dynamics, SupName) ->
+    {Pids, EStack0} = monitor_dynamic_children(Child, Dynamics),
+    Sz = ?SETS:size(Pids),
+    EStack = case Child#child.shutdown of
+                 brutal_kill ->
+                     ?SETS:fold(fun(P, _) -> exit(P, kill) end, ok, Pids),
+                     wait_dynamic_children(Child, Pids, Sz, undefined, EStack0);
+                 infinity ->
+                     ?SETS:fold(fun(P, _) -> exit(P, shutdown) end, ok, Pids),
+                     wait_dynamic_children(Child, Pids, Sz, undefined, EStack0);
+                 Time ->
+                     ?SETS:fold(fun(P, _) -> exit(P, shutdown) end, ok, Pids),
+                     TRef = erlang:start_timer(Time, self(), kill),
+                     wait_dynamic_children(Child, Pids, Sz, TRef, EStack0)
+             end,
+    %% Unrool stacked errors and report them
+    ?DICT:fold(fun(Reason, Ls, _) ->
+                       report_error(shutdown_error, Reason,
+                                    Child#child{pid=Ls}, SupName)
+               end, ok, EStack).
+
+
+monitor_dynamic_children(#child{restart_type=temporary}, Dynamics) ->
+    ?SETS:fold(fun(P, {Pids, EStack}) ->
+                       case monitor_child(P) of
+                           ok ->
+                               {?SETS:add_element(P, Pids), EStack};
+                           {error, normal} ->
+                               {Pids, EStack};
+                           {error, Reason} ->
+                               {Pids, ?DICT:append(Reason, P, EStack)}
+                       end
+               end, {?SETS:new(), ?DICT:new()}, Dynamics);
+monitor_dynamic_children(#child{restart_type=RType}, Dynamics) ->
+    ?DICT:fold(fun(P, _, {Pids, EStack}) ->
+                       case monitor_child(P) of
+                           ok ->
+                               {?SETS:add_element(P, Pids), EStack};
+                           {error, normal} when RType =/= permanent ->
+                               {Pids, EStack};
+                           {error, Reason} ->
+                               {Pids, ?DICT:append(Reason, P, EStack)}
+                       end
+               end, {?SETS:new(), ?DICT:new()}, Dynamics).
+
+
+wait_dynamic_children(_Child, _Pids, 0, undefined, EStack) ->
+    EStack;
+wait_dynamic_children(_Child, _Pids, 0, TRef, EStack) ->
+	%% If the timer has expired before its cancellation, we must empty the
+	%% mail-box of the 'timeout'-message.
+    erlang:cancel_timer(TRef),
+    receive
+        {timeout, TRef, kill} ->
+            EStack
+    after 0 ->
+            EStack
+    end;
+wait_dynamic_children(#child{shutdown=brutal_kill} = Child, Pids, Sz,
+                      TRef, EStack) ->
+    receive
+        {'DOWN', _MRef, process, Pid, killed} ->
+            wait_dynamic_children(Child, ?SETS:del_element(Pid, Pids), Sz-1,
+                                  TRef, EStack);
+
+        {'DOWN', _MRef, process, Pid, Reason} ->
+            wait_dynamic_children(Child, ?SETS:del_element(Pid, Pids), Sz-1,
+                                  TRef, ?DICT:append(Reason, Pid, EStack))
+    end;
+wait_dynamic_children(#child{restart_type=RType} = Child, Pids, Sz,
+                      TRef, EStack) ->
+    receive
+        {'DOWN', _MRef, process, Pid, shutdown} ->
+            wait_dynamic_children(Child, ?SETS:del_element(Pid, Pids), Sz-1,
+                                  TRef, EStack);
+
+        {'DOWN', _MRef, process, Pid, normal} when RType =/= permanent ->
+            wait_dynamic_children(Child, ?SETS:del_element(Pid, Pids), Sz-1,
+                                  TRef, EStack);
+
+        {'DOWN', _MRef, process, Pid, Reason} ->
+            wait_dynamic_children(Child, ?SETS:del_element(Pid, Pids), Sz-1,
+                                  TRef, ?DICT:append(Reason, Pid, EStack));
+
+        {timeout, TRef, kill} ->
+            ?SETS:fold(fun(P, _) -> exit(P, kill) end, ok, Pids),
+            wait_dynamic_children(Child, Pids, Sz-1, undefined, EStack)
+    end.
+
 %%-----------------------------------------------------------------
 %% Child/State manipulating functions.
 %%-----------------------------------------------------------------
@@ -1134,12 +1238,19 @@ report_error(Error, Reason, Child, SupName) ->
     error_logger:error_report(supervisor_report, ErrorMsg).
 
 
-extract_child(Child) ->
+extract_child(Child) when is_pid(Child#child.pid) ->
     [{pid, Child#child.pid},
      {name, Child#child.name},
      {mfargs, Child#child.mfargs},
      {restart_type, Child#child.restart_type},
      {shutdown, Child#child.shutdown},
+     {child_type, Child#child.child_type}];
+extract_child(Child) ->
+    [{nb_children, length(Child#child.pid)},
+     {name, Child#child.name},
+     {mfargs, Child#child.mfargs},
+     {restart_type, Child#child.restart_type},
+     {shutdown, Child#child.shutdown},
      {child_type, Child#child.child_type}].
 
 report_progress(Child, SupName) ->