diff options
Diffstat (limited to 'erts/emulator/test/map_SUITE.erl')
| -rw-r--r-- | erts/emulator/test/map_SUITE.erl | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/erts/emulator/test/map_SUITE.erl b/erts/emulator/test/map_SUITE.erl index 886ae7d516..1b9758c23e 100644 --- a/erts/emulator/test/map_SUITE.erl +++ b/erts/emulator/test/map_SUITE.erl @@ -58,6 +58,7 @@ %% erlang t_erlang_hash/1, t_map_encode_decode/1, + t_gc_rare_map_overflow/1, %% non specific BIF related t_bif_build_and_check/1, @@ -121,6 +122,7 @@ all() -> [ %% erlang t_erlang_hash, t_map_encode_decode, + t_gc_rare_map_overflow, t_map_size, t_is_map, %% non specific BIF related @@ -2966,3 +2968,97 @@ do_badmap_17(Config) -> %% Use this function to avoid compile-time evaluation of an expression. id(I) -> I. + + +%% OTP-13146 +%% Provoke major GC with a lot of "fat" maps on external format in msg queue +%% causing heap fragments to be allocated. +t_gc_rare_map_overflow(Config) -> + Pa = filename:dirname(code:which(?MODULE)), + {ok, Node} = test_server:start_node(gc_rare_map_overflow, slave, [{args, "-pa \""++Pa++"\""}]), + Echo = spawn_link(Node, fun Loop() -> receive {From,Msg} -> From ! Msg + end, + Loop() + end), + FatMap = fatmap(34), + false = (flatmap =:= erts_internal:map_type(FatMap)), + + t_gc_rare_map_overflow_do(Echo, FatMap, fun() -> erlang:garbage_collect() end), + + % Repeat test for minor gc: + minor_collect(), % need this to make the next gc really be a minor + t_gc_rare_map_overflow_do(Echo, FatMap, fun() -> true = minor_collect() end), + + unlink(Echo), + test_server:stop_node(Node). + +t_gc_rare_map_overflow_do(Echo, FatMap, GcFun) -> + Master = self(), + true = receive M -> false after 0 -> true end, % assert empty msg queue + Echo ! {Master, token}, + repeat(1000, fun(_) -> Echo ! {Master, FatMap} end, void), + + timer:sleep(100), % Wait for maps to arrive in our msg queue + token = receive Tok -> Tok end, % and provoke move from outer to inner msg queue + + %% Do GC that will "overflow" and create heap frags due to all the fat maps + GcFun(), + + %% Now check that all maps in msg queueu are intact + %% Will crash emulator in OTP-18.1 + repeat(1000, fun(_) -> FatMap = receive FM -> FM end end, void), + ok. + +minor_collect() -> + minor_collect(minor_gcs()). + +minor_collect(Before) -> + After = minor_gcs(), + case After of + _ when After > Before -> true; + _ when After =:= Before -> minor_collect(Before); + 0 -> false + end. + +minor_gcs() -> + {garbage_collection, Info} = process_info(self(), garbage_collection), + {minor_gcs, GCS} = lists:keyfind(minor_gcs, 1, Info), + GCS. + +%% Generate a map with N (or N+1) keys that has an abnormal heap demand. +%% Done by finding keys that collide in the first 32-bit hash. +fatmap(N) -> + erts_debug:set_internal_state(available_internal_state, true), + Table = ets:new(void, [bag, private]), + + Seed0 = rand:seed_s(exsplus, {4711, 3141592, 2718281}), + Seed1 = fatmap_populate(Table, Seed0, (1 bsl 16)), + Keys = fatmap_generate(Table, Seed1, N, []), + ets:delete(Table), + maps:from_list([{K,K} || K <- Keys]). + +fatmap_populate(_, Seed, 0) -> Seed; +fatmap_populate(Table, Seed, N) -> + {I, NextSeed} = rand:uniform_s(1 bsl 48, Seed), + Hash = internal_hash(I), + ets:insert(Table, [{Hash, I}]), + fatmap_populate(Table, NextSeed, N-1). + + +fatmap_generate(_, _, N, Acc) when N =< 0 -> + Acc; +fatmap_generate(Table, Seed, N0, Acc0) -> + {I, NextSeed} = rand:uniform_s(1 bsl 48, Seed), + Hash = internal_hash(I), + case ets:member(Table, Hash) of + true -> + NewKeys = [I | ets:lookup_element(Table, Hash, 2)], + Acc1 = lists:usort(Acc0 ++ NewKeys), + N1 = N0 - (length(Acc1) - length(Acc0)), + fatmap_generate(Table, NextSeed, N1, Acc1); + false -> + fatmap_generate(Table, NextSeed, N0, Acc0) + end. + +internal_hash(Term) -> + erts_debug:get_internal_state({internal_hash, Term}). |