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-rw-r--r--lib/stdlib/doc/src/supervisor.xml38
-rw-r--r--lib/stdlib/src/supervisor.erl49
-rw-r--r--lib/stdlib/test/supervisor_SUITE.erl175
3 files changed, 247 insertions, 15 deletions
diff --git a/lib/stdlib/doc/src/supervisor.xml b/lib/stdlib/doc/src/supervisor.xml
index adf9d24eae..fb2ec9ba67 100644
--- a/lib/stdlib/doc/src/supervisor.xml
+++ b/lib/stdlib/doc/src/supervisor.xml
@@ -402,9 +402,12 @@ child_spec() = {Id,StartFunc,Restart,Shutdown,Type,Modules}
<v>&nbsp;Module = atom()</v>
</type>
<desc>
- <p>Returns a list with information about all child
+ <p>Returns a newly created list with information about all child
specifications and child processes belonging to
the supervisor <c>SupRef</c>.</p>
+ <p>Note that calling this function when supervising a large
+ number of children under low memory conditions can cause an
+ out of memory exception.</p>
<p>See <c>start_child/2</c> for a description of <c>SupRef</c>.</p>
<p>The information given for each child specification/process
is:</p>
@@ -428,6 +431,39 @@ child_spec() = {Id,StartFunc,Restart,Shutdown,Type,Modules}
</desc>
</func>
<func>
+ <name>count_children(SupRef) -> PropListOfCounts</name>
+ <fsummary>Return counts for the number of childspecs, active children, supervisors and workers.</fsummary>
+ <type>
+ <v>SupRef = Name | {Name,Node} | {global,Name} | pid()</v>
+ <v>&nbsp;Name = Node = atom()</v>
+ <v>PropListOfCounts = [{specs, ChildSpecCount}, {active, ActiveProcessCount}, {supervisors, ChildSupervisorCount}, {workers, ChildWorkerCount}]</v>
+ </type>
+ <desc>
+ <p>Returns a property list (see <c>proplists</c>) containing the
+ counts for each of the following elements of the supervisor's
+ child specifications and managed processes:</p>
+ <list type="bulleted">
+ <item>
+ <p><c>specs</c> - the total count of children, dead or alive.</p>
+ </item>
+ <item>
+ <p><c>active</c> - the count of all actively running child processes
+ managed by this supervisor.</p>
+ </item>
+ <item>
+ <p><c>supervisors</c> - the count of all children marked as
+ child_type = supervisor in the spec list, whether or not the
+ child process is still alive.</p>
+ </item>
+ <item>
+ <p><c>workers</c> - the count of all children marked as
+ child_type = worker in the spec list, whether or not the child
+ process is still alive.</p>
+ </item>
+ </list>
+ </desc>
+ </func>
+ <func>
<name>check_childspecs([ChildSpec]) -> Result</name>
<fsummary>Check if children specifications are syntactically correct.</fsummary>
<type>
diff --git a/lib/stdlib/src/supervisor.erl b/lib/stdlib/src/supervisor.erl
index fb1303d1eb..342b71f2da 100644
--- a/lib/stdlib/src/supervisor.erl
+++ b/lib/stdlib/src/supervisor.erl
@@ -24,7 +24,7 @@
-export([start_link/2,start_link/3,
start_child/2, restart_child/2,
delete_child/2, terminate_child/2,
- which_children/1,
+ which_children/1, count_children/1,
check_childspecs/1]).
-export([behaviour_info/1]).
@@ -95,6 +95,9 @@ terminate_child(Supervisor, Name) ->
which_children(Supervisor) ->
call(Supervisor, which_children).
+count_children(Supervisor) ->
+ call(Supervisor, count_children).
+
call(Supervisor, Req) ->
gen_server:call(Supervisor, Req, infinity).
@@ -297,7 +300,49 @@ handle_call(which_children, _From, State) ->
{Name, Pid, ChildType, Mods}
end,
State#state.children),
- {reply, Resp, State}.
+ {reply, Resp, State};
+
+handle_call(count_children, _From, State) when ?is_simple(State) ->
+ [#child{child_type = CT}] = State#state.children,
+ {Active, Count} =
+ ?DICT:fold(fun(Pid, _Val, {Alive, Tot}) ->
+ if is_pid(Pid) -> {Alive+1, Tot +1};
+ true -> {Alive, Tot + 1} end
+ end, {0, 0}, State#state.dynamics),
+ Reply = case CT of
+ supervisor -> [{specs, 1}, {active, Active},
+ {supervisors, Count}, {workers, 0}];
+ worker -> [{specs, 1}, {active, Active},
+ {supervisors, 0}, {workers, Count}]
+ end,
+ {reply, Reply, State};
+
+handle_call(count_children, _From, State) ->
+
+ %% Specs and children are together on the children list...
+ {Specs, Active, Supers, Workers} =
+ lists:foldl(fun(Child, Counts) ->
+ count_child(Child, Counts)
+ end, {0,0,0,0}, State#state.children),
+
+ %% Reformat counts to a property list.
+ Reply = [{specs, Specs}, {active, Active},
+ {supervisors, Supers}, {workers, Workers}],
+ {reply, Reply, State}.
+
+
+count_child(#child{pid = Pid, child_type = worker},
+ {Specs, Active, Supers, Workers}) ->
+ case is_pid(Pid) andalso is_process_alive(Pid) of
+ true -> {Specs+1, Active+1, Supers, Workers+1};
+ false -> {Specs+1, Active, Supers, Workers+1}
+ end;
+count_child(#child{pid = Pid, child_type = supervisor},
+ {Specs, Active, Supers, Workers}) ->
+ case is_pid(Pid) andalso is_process_alive(Pid) of
+ true -> {Specs+1, Active+1, Supers+1, Workers};
+ false -> {Specs+1, Active, Supers+1, Workers}
+ end.
%%% Hopefully cause a function-clause as there is no API function
diff --git a/lib/stdlib/test/supervisor_SUITE.erl b/lib/stdlib/test/supervisor_SUITE.erl
index f25e877289..039ea298c4 100644
--- a/lib/stdlib/test/supervisor_SUITE.erl
+++ b/lib/stdlib/test/supervisor_SUITE.erl
@@ -50,7 +50,7 @@
simple_one_for_one_extra/1]).
%% Misc tests
--export([child_unlink/1, tree/1]).
+-export([child_unlink/1, tree/1, count_children_memory/1]).
%-------------------------------------------------------------------------
@@ -60,7 +60,8 @@ all(suite) ->
child_adm_simple, extra_return, child_specs,
restart_one_for_one, restart_one_for_all,
restart_simple_one_for_one, restart_rest_for_one,
- normal_termination, abnormal_termination, child_unlink, tree]}.
+ normal_termination, abnormal_termination, child_unlink, tree,
+ count_children_memory]}.
start(InitResult) ->
@@ -72,6 +73,15 @@ init(fail) ->
init(InitResult) ->
InitResult.
+%% Respect proplist return of supervisor:count_children
+get_child_counts(Supervisor) ->
+ Counts = supervisor:count_children(Supervisor),
+ [proplists:get_value(specs, Counts),
+ proplists:get_value(active, Counts),
+ proplists:get_value(supervisors, Counts),
+ proplists:get_value(workers, Counts)].
+
+
%-------------------------------------------------------------------------
%
% Test cases starts here.
@@ -140,6 +150,8 @@ sup_start_ignore_child(Config) when is_list(Config) ->
?line [{child2, CPid2, worker, []},{child1, undefined, worker, []}]
= supervisor:which_children(sup_test),
+ ?line [2,1,0,2] = get_child_counts(sup_test),
+
ok.
%-------------------------------------------------------------------------
@@ -341,6 +353,8 @@ extra_return(Config) when is_list(Config) ->
?line {error, running} = supervisor:delete_child(sup_test, child1),
?line {error, running} = supervisor:restart_child(sup_test, child1),
?line [{child1, CPid, worker, []}] = supervisor:which_children(sup_test),
+ ?line [1,1,0,1] = get_child_counts(sup_test),
+
?line ok = supervisor:terminate_child(sup_test, child1),
receive
{'EXIT', CPid, shutdown} -> ok;
@@ -350,22 +364,31 @@ extra_return(Config) when is_list(Config) ->
?line test_server:fail(no_child_termination)
end,
?line [{child1,undefined,worker,[]}] = supervisor:which_children(sup_test),
+ ?line [1,0,0,1] = get_child_counts(sup_test),
+
?line {ok, CPid2,extra_return} =
supervisor:restart_child(sup_test, child1),
?line [{child1, CPid2, worker, []}] = supervisor:which_children(sup_test),
+ ?line [1,1,0,1] = get_child_counts(sup_test),
+
?line ok = supervisor:terminate_child(sup_test, child1),
?line ok = supervisor:terminate_child(sup_test, child1),
?line ok = supervisor:delete_child(sup_test, child1),
?line {error, not_found} = supervisor:restart_child(sup_test, child1),
?line [] = supervisor:which_children(sup_test),
+ ?line [0,0,0,0] = get_child_counts(sup_test),
+
?line {ok, CPid3, extra_return} = supervisor:start_child(sup_test, Child),
?line [{child1, CPid3, worker, []}] = supervisor:which_children(sup_test),
+ ?line [1,1,0,1] = get_child_counts(sup_test),
+
ok.
%-------------------------------------------------------------------------
child_adm(doc)->
["Test API functions start_child/2, terminate_child/2, delete_child/2 "
- "restart_child/2, which_children/1. Only correct childspecs are used, "
- "handling of incorrect childspecs is tested in child_specs/1"];
+ "restart_child/2, which_children/1, count_children/1. Only correct "
+ "childspecs are used, handling of incorrect childspecs is tested in "
+ "child_specs/1"];
child_adm(suite) -> [];
child_adm(Config) when is_list(Config) ->
process_flag(trap_exit, true),
@@ -373,6 +396,7 @@ child_adm(Config) when is_list(Config) ->
worker, []},
?line {ok, _Pid} = start({ok, {{one_for_one, 2, 3600}, [Child]}}),
?line [{child1, CPid, worker, []}] = supervisor:which_children(sup_test),
+ ?line [1,1,0,1] = get_child_counts(sup_test),
link(CPid),
%% Start of an already runnig process
@@ -392,6 +416,7 @@ child_adm(Config) when is_list(Config) ->
?line test_server:fail(no_child_termination)
end,
?line [{child1,undefined,worker,[]}] = supervisor:which_children(sup_test),
+ ?line [1,0,0,1] = get_child_counts(sup_test),
%% Like deleting something that does not exist, it will succeed!
?line ok = supervisor:terminate_child(sup_test, child1),
@@ -402,6 +427,7 @@ child_adm(Config) when is_list(Config) ->
%% Restart
?line {ok, CPid2} = supervisor:restart_child(sup_test, child1),
?line [{child1, CPid2, worker, []}] = supervisor:which_children(sup_test),
+ ?line [1,1,0,1] = get_child_counts(sup_test),
?line {error, running} = supervisor:restart_child(sup_test, child1),
?line {error, not_found} = supervisor:restart_child(sup_test, child2),
@@ -414,15 +440,19 @@ child_adm(Config) when is_list(Config) ->
?line ok = supervisor:delete_child(sup_test, child1),
?line {error, not_found} = supervisor:restart_child(sup_test, child1),
?line [] = supervisor:which_children(sup_test),
+ ?line [0,0,0,0] = get_child_counts(sup_test),
%% Start
?line {'EXIT',{noproc,{gen_server,call, _}}} =
(catch supervisor:start_child(foo, Child)),
?line {ok, CPid3} = supervisor:start_child(sup_test, Child),
?line [{child1, CPid3, worker, []}] = supervisor:which_children(sup_test),
+ ?line [1,1,0,1] = get_child_counts(sup_test),
?line {'EXIT',{noproc,{gen_server,call,[foo,which_children,infinity]}}}
= (catch supervisor:which_children(foo)),
+ ?line {'EXIT',{noproc,{gen_server,call,[foo,count_children,infinity]}}}
+ = (catch supervisor:count_children(foo)),
ok.
%-------------------------------------------------------------------------
child_adm_simple(doc) ->
@@ -436,6 +466,7 @@ child_adm_simple(Config) when is_list(Config) ->
?line {ok, _Pid} = start({ok, {{simple_one_for_one, 2, 3600}, [Child]}}),
%% In simple_one_for_one all children are added dynamically
?line [] = supervisor:which_children(sup_test),
+ ?line [1,0,0,0] = get_child_counts(sup_test),
%% Start
?line {'EXIT',{noproc,{gen_server,call, _}}} =
@@ -443,12 +474,14 @@ child_adm_simple(Config) when is_list(Config) ->
?line {ok, CPid1} = supervisor:start_child(sup_test, []),
?line [{undefined, CPid1, worker, []}] =
supervisor:which_children(sup_test),
+ ?line [1,1,0,1] = get_child_counts(sup_test),
?line {ok, CPid2} = supervisor:start_child(sup_test, []),
?line Children = supervisor:which_children(sup_test),
?line 2 = length(Children),
?line true = lists:member({undefined, CPid2, worker, []}, Children),
?line true = lists:member({undefined, CPid1, worker, []}, Children),
+ ?line [1,2,0,2] = get_child_counts(sup_test),
%% Termination
?line {error, simple_one_for_one} =
@@ -541,8 +574,10 @@ permanent_normal(Config) when is_list(Config) ->
ok;
false ->
?line test_server:fail({permanent_child_not_restarted, Child1})
- end.
+ end,
+ ?line [1,1,0,1] = get_child_counts(sup_test),
+ ok.
%-------------------------------------------------------------------------
transient_normal(doc) ->
["A transient child should not be restarted if it exits with "
@@ -558,8 +593,10 @@ transient_normal(Config) when is_list(Config) ->
CPid1 ! stop,
test_server:sleep(100),
- ?line [{child1,undefined,worker,[]}] = supervisor:which_children(sup_test).
+ ?line [{child1,undefined,worker,[]}] = supervisor:which_children(sup_test),
+ ?line [1,0,0,1] = get_child_counts(sup_test),
+ ok.
%-------------------------------------------------------------------------
temporary_normal(doc) ->
["A temporary process should never be restarted"];
@@ -574,8 +611,10 @@ temporary_normal(Config) when is_list(Config) ->
CPid1 ! stop,
test_server:sleep(100),
- ?line [{child1,undefined,worker,[]}] = supervisor:which_children(sup_test).
+ ?line [{child1,undefined,worker,[]}] = supervisor:which_children(sup_test),
+ ?line [1,0,0,1] = get_child_counts(sup_test),
+ ok.
%-------------------------------------------------------------------------
abnormal_termination(doc) ->
["Testes the supervisors behaviour if a child dies with reason abnormal"];
@@ -601,8 +640,10 @@ permanent_abnormal(Config) when is_list(Config) ->
ok;
false ->
?line test_server:fail({permanent_child_not_restarted, Child1})
- end.
+ end,
+ ?line [1,1,0,1] = get_child_counts(sup_test),
+ ok.
%-------------------------------------------------------------------------
transient_abnormal(doc) ->
["A transient child should be restarted if it exits with "
@@ -624,9 +665,10 @@ transient_abnormal(Config) when is_list(Config) ->
ok;
false ->
?line test_server:fail({transient_child_not_restarted, Child1})
- end.
-
+ end,
+ ?line [1,1,0,1] = get_child_counts(sup_test),
+ ok.
%-------------------------------------------------------------------------
temporary_abnormal(doc) ->
["A temporary process should never be restarted"];
@@ -641,8 +683,10 @@ temporary_abnormal(Config) when is_list(Config) ->
CPid1 ! die,
test_server:sleep(100),
- ?line [{child1,undefined,worker,[]}] = supervisor:which_children(sup_test).
+ ?line [{child1,undefined,worker,[]}] = supervisor:which_children(sup_test),
+ ?line [1,0,0,1] = get_child_counts(sup_test),
+ ok.
%-------------------------------------------------------------------------
restart_one_for_one(doc) ->
["Test that the one_for_one strategy works."];
@@ -679,6 +723,7 @@ one_for_one(Config) when is_list(Config) ->
end;
true -> ?line test_server:fail({bad_child_list, Children})
end,
+ ?line [2,2,0,2] = get_child_counts(sup_test),
%% Test restart frequency property
CPid2 ! die,
@@ -772,6 +817,8 @@ one_for_all(Config) when is_list(Config) ->
true -> ?line test_server:fail(bad_child);
false -> ok
end,
+ ?line [2,2,0,2] = get_child_counts(sup_test),
+
%%% Test restart frequency property
[{_, Pid3, _, _}|_] = supervisor:which_children(sup_test),
Pid3 ! die,
@@ -854,6 +901,8 @@ simple_one_for_one(Config) when is_list(Config) ->
end;
true -> ?line test_server:fail({bad_child_list, Children})
end,
+ ?line [1,2,0,2] = get_child_counts(sup_test),
+
%% Test restart frequency property
CPid2 ! die,
receive
@@ -896,6 +945,8 @@ simple_one_for_one_extra(Config) when is_list(Config) ->
end;
true -> ?line test_server:fail({bad_child_list, Children})
end,
+ ?line [1,2,0,2] = get_child_counts(sup_test),
+
CPid2 ! die,
receive
{'EXIT', CPid2, _} -> ok
@@ -962,6 +1013,8 @@ rest_for_one(Config) when is_list(Config) ->
link(CPid2),
?line {ok, CPid3} = supervisor:start_child(sup_test, Child3),
link(CPid3),
+ ?line [3,3,0,3] = get_child_counts(sup_test),
+
CPid2 ! die,
receive
{'EXIT', CPid2, died} -> ok;
@@ -987,6 +1040,8 @@ rest_for_one(Config) when is_list(Config) ->
if length(Children) == 3 -> ok;
true -> ?line test_server:fail({bad_child_list, Children})
end,
+ ?line [3,3,0,3] = get_child_counts(sup_test),
+
%% Test that no old children is still alive
SCh = lists:map(fun({_,P,_,_}) -> P end, Children),
case lists:member(CPid1, SCh) of
@@ -1114,15 +1169,19 @@ tree(Config) when is_list(Config) ->
%% Child supervisors
?line {ok, Sup1} = supervisor:start_child(Pid, ChildSup1),
?line {ok, Sup2} = supervisor:start_child(Pid, ChildSup2),
+ ?line [2,2,2,0] = get_child_counts(Pid),
%% Workers
-
?line [{_, CPid2, _, _},{_, CPid1, _, _}] =
supervisor:which_children(Sup1),
+ ?line [2,2,0,2] = get_child_counts(Sup1),
+ ?line [0,0,0,0] = get_child_counts(Sup2),
%% Dynamic children
?line {ok, CPid3} = supervisor:start_child(Sup2, Child3),
?line {ok, CPid4} = supervisor:start_child(Sup2, Child4),
+ ?line [2,2,0,2] = get_child_counts(Sup1),
+ ?line [2,2,0,2] = get_child_counts(Sup2),
link(Sup1),
link(Sup2),
@@ -1144,9 +1203,11 @@ tree(Config) when is_list(Config) ->
?line [{_, CPid2, _, _},{_, CPid1, _, _}] =
supervisor:which_children(Sup1),
+ ?line [2,2,0,2] = get_child_counts(Sup1),
?line [{_, NewCPid4, _, _},{_, CPid3, _, _}] =
supervisor:which_children(Sup2),
+ ?line [2,2,0,2] = get_child_counts(Sup2),
link(NewCPid4),
@@ -1195,9 +1256,99 @@ tree(Config) when is_list(Config) ->
?line [{supchild2, NewSup2, _, _},{supchild1, NewSup1, _, _}] =
supervisor:which_children(Pid),
+ ?line [2,2,2,0] = get_child_counts(Pid),
?line [{child2, _, _, _},{child1, _, _, _}] =
supervisor:which_children(NewSup1),
+ ?line [2,2,0,2] = get_child_counts(NewSup1),
+
?line [] = supervisor:which_children(NewSup2),
+ ?line [0,0,0,0] = get_child_counts(NewSup2),
ok.
+%-------------------------------------------------------------------------
+count_children_allocator_test(MemoryState) ->
+ Allocators = [temp_alloc, eheap_alloc, binary_alloc, ets_alloc,
+ driver_alloc, sl_alloc, ll_alloc, fix_alloc, std_alloc,
+ sys_alloc],
+ MemoryStateList = element(4, MemoryState),
+ AllocTypes = [lists:keyfind(Alloc, 1, MemoryStateList)
+ || Alloc <- Allocators],
+ AllocStates = [lists:keyfind(e, 1, AllocValue)
+ || {_Type, AllocValue} <- AllocTypes],
+ lists:all(fun(State) -> State == {e, true} end, AllocStates).
+
+count_children_memory(doc) ->
+ ["Test that which_children eats memory, but count_children does not."];
+count_children_memory(suite) ->
+ MemoryState = erlang:system_info(allocator),
+ case count_children_allocator_test(MemoryState) of
+ true -> [];
+ false ->
+ {skip, "+Meamin used during test; erlang:memory/1 not available"}
+ end;
+count_children_memory(Config) when is_list(Config) ->
+ process_flag(trap_exit, true),
+ Child = {child, {supervisor_1, start_child, []}, temporary, 1000,
+ worker, []},
+ ?line {ok, _Pid} = start({ok, {{simple_one_for_one, 2, 3600}, [Child]}}),
+ [supervisor:start_child(sup_test, []) || _Ignore <- lists:seq(1,1000)],
+
+ garbage_collect(),
+ _Size1 = erlang:memory(processes_used),
+ Children = supervisor:which_children(sup_test),
+ _Size2 = erlang:memory(processes_used),
+ ChildCount = get_child_counts(sup_test),
+ Size3 = erlang:memory(processes_used),
+
+ [supervisor:start_child(sup_test, []) || _Ignore2 <- lists:seq(1,1000)],
+
+ garbage_collect(),
+ Children2 = supervisor:which_children(sup_test),
+ Size4 = erlang:memory(processes_used),
+ ChildCount2 = get_child_counts(sup_test),
+ Size5 = erlang:memory(processes_used),
+
+ garbage_collect(),
+ Children3 = supervisor:which_children(sup_test),
+ Size6 = erlang:memory(processes_used),
+ ChildCount3 = get_child_counts(sup_test),
+ Size7 = erlang:memory(processes_used),
+
+ ?line 1000 = length(Children),
+ ?line [1,1000,0,1000] = ChildCount,
+ ?line 2000 = length(Children2),
+ ?line [1,2000,0,2000] = ChildCount2,
+ ?line Children3 = Children2,
+ ?line ChildCount3 = ChildCount2,
+
+ %% count_children consumes memory using an accumulator function,
+ %% but the space can be reclaimed incrementally, whereas
+ %% which_children generates a return list.
+ case (Size5 =< Size4) of
+ true -> ok;
+ false ->
+ ?line test_server:fail({count_children, used_more_memory})
+ end,
+ case Size7 =< Size6 of
+ true -> ok;
+ false ->
+ ?line test_server:fail({count_children, used_more_memory})
+ end,
+
+ case Size4 > Size3 of
+ true -> ok;
+ false ->
+ ?line test_server:fail({which_children, used_no_memory})
+ end,
+ case Size6 > Size5 of
+ true -> ok;
+ false ->
+ ?line test_server:fail({which_children, used_no_memory})
+ end,
+
+ [exit(Pid, kill) || {undefined, Pid, worker, _Modules} <- Children3],
+ test_server:sleep(100),
+ ?line [1,0,0,0] = get_child_counts(sup_test),
+
+ ok.
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-12 13:50:31 +0000