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Stack errors when dynamic children are stopped
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Because a simple_one_for_one supervisor can have many workers, we stack
errors during its shutdown to report only one message for each encountered
error type. Instead of reporting the child's pid, we use the number of
concerned children.
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Christopher Faulet committed Sep 14, 2011
1 parent c35108d commit bddb627
Showing 1 changed file with 63 additions and 60 deletions.
123 changes: 63 additions & 60 deletions lib/stdlib/src/supervisor.erl
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Expand Up @@ -849,96 +849,92 @@ monitor_child(Pid) ->
%% can have an significative overhead here.
%%-----------------------------------------------------------------
terminate_dynamic_children(Child, Dynamics, SupName) ->
Pids = monitor_dynamic_children(Child, Dynamics, SupName),
Sz = ?SETS:size(Pids),
case Child#child.shutdown of
brutal_kill ->
?SETS:fold(fun(P, _) -> exit(P, kill) end, ok, Pids),
wait_dynamic_children(Child, Pids, SupName, Sz, undefined);
infinity ->
?SETS:fold(fun(P, _) -> exit(P, shutdown) end, ok, Pids),
wait_dynamic_children(Child, Pids, SupName, Sz, undefined);
Time ->
?SETS:fold(fun(P, _) -> exit(P, shutdown) end, ok, Pids),
TRef = erlang:start_timer(Time, self(), kill),
wait_dynamic_children(Child, Pids, SupName, Sz, TRef)
end.


monitor_dynamic_children(#child{restart_type=temporary} = Child,
Dynamics, SupName) ->
?SETS:fold(fun(P, Acc) ->
{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, Acc);
{?SETS:add_element(P, Pids), EStack};
{error, normal} ->
Acc;
{error, OtherReason} ->
report_error(shutdown_error, OtherReason,
Child#child{pid=P}, SupName),
Acc
{Pids, EStack};
{error, Reason} ->
{Pids, ?DICT:append(Reason, P, EStack)}
end
end, ?SETS:new(), Dynamics);
monitor_dynamic_children(#child{restart_type=RType} = Child,
Dynamics, SupName) ->
?DICT:fold(fun(P, _, Acc) ->
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, Acc);
{?SETS:add_element(P, Pids), EStack};
{error, normal} when RType =/= permanent ->
Acc;
{error, OtherReason} ->
report_error(shutdown_error, OtherReason,
Child#child{pid=P}, SupName),
Acc
{Pids, EStack};
{error, Reason} ->
{Pids, ?DICT:append(Reason, P, EStack)}
end
end, ?SETS:new(), Dynamics).

end, {?SETS:new(), ?DICT:new()}, Dynamics).


wait_dynamic_children(_Child, _Pids, _SupName, 0, undefined) ->
ok;
wait_dynamic_children(_Child, _Pids, _SupName, 0, TRef) ->
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} ->
ok
EStack
after 0 ->
ok
EStack
end;
wait_dynamic_children(#child{shutdown=brutal_kill} = Child,
Pids, SupName, Sz, TRef) ->
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), SupName,
Sz-1, TRef);
wait_dynamic_children(Child, ?SETS:del_element(Pid, Pids), Sz-1,
TRef, EStack);

{'DOWN', _MRef, process, Pid, Reason} ->
report_error(shutdown_error, Reason, Child#child{pid=Pid}, SupName),
wait_dynamic_children(Child, ?SETS:del_element(Pid, Pids), SupName,
Sz-1, TRef)
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,
SupName, Sz, TRef) ->
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), SupName,
Sz-1, TRef);
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), SupName,
Sz-1, TRef);
wait_dynamic_children(Child, ?SETS:del_element(Pid, Pids), Sz-1,
TRef, EStack);

{'DOWN', _MRef, process, Pid, Reason} ->
report_error(shutdown_error, Reason, Child#child{pid=Pid}, SupName),
wait_dynamic_children(Child, ?SETS:del_element(Pid, Pids), SupName,
Sz-1, TRef);
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, SupName, Sz, undefined)
wait_dynamic_children(Child, Pids, Sz-1, undefined, EStack)
end.

%%-----------------------------------------------------------------
Expand Down Expand Up @@ -1243,8 +1239,15 @@ 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},
Expand Down

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