%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2016. 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(ref_cell).
-export([start_link/0, start_link_deep/0, call/2]).
-compile(native).
-define(DEPTH, 100).
-define(ALLOCS, 500).
start_link() ->
spawn_link(fun() -> loop(undefined) end).
start_link_deep() ->
spawn_link(fun() -> go_deep(?DEPTH) end).
%% Create a stack large enough to get a graylimit trap placed next time there's
%% a minor gc.
go_deep(0) ->
alloc_some(?ALLOCS),
loop(undefined),
0;
go_deep(Depth) ->
go_deep(Depth-1)+1.
%% Do some allocation to trigger a minor gc
alloc_some(Amount) ->
Check = (Amount * (Amount + 1)) div 2,
Check = lists:sum(lists:seq(1, Amount)).
call(Pid, Call) ->
Pid ! {Call, self()},
receive {Pid, Res} -> Res end.
loop(Thing) ->
receive
{done, Pid} -> Pid ! {self(), done};
{{put_res_of, Fun}, Pid} ->
NewThing = Fun(),
Pid ! {self(), put},
loop(NewThing);
{get, Pid} ->
Pid ! {self(), Thing},
loop(Thing)
end.
