From d468fcbb1dfeef6c68f6033df9bff57dfcd748af Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?John=20H=C3=B6gberg?= Date: Wed, 10 Jan 2018 13:34:05 +0100 Subject: Reduce memory use of system_information:to_file/1 The previous implementation generated a term, converted it to plain text with io_lib:format/2, and then converted that to a binary before writing it to disk. We now emit the term as we go, which should make it a bit safer to extract this information under load. --- lib/runtime_tools/src/system_information.erl | 232 ++++++++++++++++++--------- 1 file changed, 158 insertions(+), 74 deletions(-) (limited to 'lib/runtime_tools/src') diff --git a/lib/runtime_tools/src/system_information.erl b/lib/runtime_tools/src/system_information.erl index df25297eb9..6a9f3ff58a 100644 --- a/lib/runtime_tools/src/system_information.erl +++ b/lib/runtime_tools/src/system_information.erl @@ -75,43 +75,37 @@ load_report(file, File) -> load_report(data, from_file(File)); load_report(data, Report) -> ok = start_internal(), gen_server:call(?SERVER, {load_report, Report}, infinity). -report() -> [ - {init_arguments, init:get_arguments()}, - {code_paths, code:get_path()}, - {code, code()}, - {system_info, erlang_system_info()}, - {erts_compile_info, erlang:system_info(compile_info)}, - {beam_dynamic_libraries, get_dynamic_libraries()}, - {environment_erts, os_getenv_erts_specific()}, - {environment, [split_env(Env) || Env <- os:getenv()]}, - {sanity_check, sanity_check()} - ]. +report() -> + %% This is ugly but beats having to maintain two distinct implementations, + %% and we don't really care about memory use since it's internal and + %% undocumented. + {ok, Fd} = file:open([], [ram, read, write]), + to_fd(Fd), + {ok, _} = file:position(Fd, bof), + from_fd(Fd). -spec to_file(FileName) -> ok | {error, Reason} when FileName :: file:name_all(), Reason :: file:posix() | badarg | terminated | system_limit. to_file(File) -> - file:write_file(File, iolist_to_binary([ - io_lib:format("{system_information_version, ~p}.~n", [ - ?REPORT_FILE_VSN - ]), - io_lib:format("{system_information, ~p}.~n", [ - report() - ]) - ])). + case file:open(File, [raw, write, binary, delayed_write]) of + {ok, Fd} -> + try + to_fd(Fd) + after + file:close(Fd) + end; + {error, Reason} -> + {error, Reason} + end. from_file(File) -> - case file:consult(File) of - {ok, Data} -> - case get_value([system_information_version], Data) of - ?REPORT_FILE_VSN -> - get_value([system_information], Data); - Vsn -> - erlang:error({unknown_version, Vsn}) - end; - _ -> - erlang:error(bad_report_file) + {ok, Fd} = file:open(File, [raw, read]), + try + from_fd(Fd) + after + file:close(Fd) end. applications() -> applications([]). @@ -457,61 +451,151 @@ split_env([$=|Vs], Key) -> {lists:reverse(Key), Vs}; split_env([I|Vs], Key) -> split_env(Vs, [I|Key]); split_env([], KV) -> lists:reverse(KV). % should not happen. -%% get applications +from_fd(Fd) -> + try + [{system_information_version, "1.0"}, + {system_information, Data}] = consult_fd(Fd), + Data + catch + _:_ -> erlang:error(bad_report_file) + end. -code() -> - % order is important - get_code_from_paths(code:get_path()). +consult_fd(Fd) -> + consult_fd_1(Fd, [], {ok, []}). +consult_fd_1(Fd, Cont0, ReadResult) -> + Data = + case ReadResult of + {ok, Characters} -> Characters; + eof -> eof + end, + case erl_scan:tokens(Cont0, Data, 1) of + {done, {ok, Tokens, _}, Next} -> + {ok, Term} = erl_parse:parse_term(Tokens), + [Term | consult_fd_1(Fd, [], {ok, Next})]; + {more, Cont} -> + consult_fd_1(Fd, Cont, file:read(Fd, 1 bsl 20)); + {done, {eof, _}, eof} -> [] + end. -get_code_from_paths([]) -> []; -get_code_from_paths([Path|Paths]) -> - case is_application_path(Path) of - true -> - [{application, get_application_from_path(Path)}|get_code_from_paths(Paths)]; - false -> - [{code, [ - {path, Path}, - {modules, get_modules_from_path(Path)} - ]}|get_code_from_paths(Paths)] +%% +%% Dumps a system_information tuple to the given Fd, writing the term in chunks +%% to avoid eating too much memory on large systems. +%% + +to_fd(Fd) -> + EmitChunk = + fun(Format, Args) -> + ok = file:write(Fd, io_lib:format(Format, Args)) + end, + + EmitChunk("{system_information_version, ~p}.~n" + "{system_information,[" + "{init_arguments,~p}," + "{code_paths,~p},", + [?REPORT_FILE_VSN, + init:get_arguments(), + code:get_path()]), + + emit_code_info(EmitChunk), + + EmitChunk( "," %% Note the leading comma! + "{system_info,~p}," + "{erts_compile_info,~p}," + "{beam_dynamic_libraries,~p}," + "{environment_erts,~p}," + "{environment,~p}," + "{sanity_check,~p}" + "]}.~n", + [erlang_system_info(), + erlang:system_info(compile_info), + get_dynamic_libraries(), + os_getenv_erts_specific(), + [split_env(Env) || Env <- os:getenv()], + sanity_check()]). + +%% Emits all modules/applications in the *code path order* +emit_code_info(EmitChunk) -> + EmitChunk("{code, [", []), + comma_separated_foreach(EmitChunk, + fun(Path) -> + case is_application_path(Path) of + true -> emit_application_info(EmitChunk, Path); + false -> emit_code_path_info(EmitChunk, Path) + end + end, code:get_path()), + EmitChunk("]}", []). + +emit_application_info(EmitChunk, Path) -> + [Appfile|_] = filelib:wildcard(filename:join(Path, "*.app")), + case file:consult(Appfile) of + {ok, [{application, App, Info}]} -> + RtDeps = proplists:get_value(runtime_dependencies, Info, []), + Description = proplists:get_value(description, Info, []), + Version = proplists:get_value(vsn, Info, []), + + EmitChunk("{application, {~p,[" + "{description,~p}," + "{vsn,~p}," + "{path,~p}," + "{runtime_dependencies,~p},", + [App, Description, Version, Path, RtDeps]), + emit_module_info_from_path(EmitChunk, Path), + EmitChunk("]}}", []) end. +emit_code_path_info(EmitChunk, Path) -> + EmitChunk("{code, [" + "{path, ~p},", [Path]), + emit_module_info_from_path(EmitChunk, Path), + EmitChunk("]}", []). + +emit_module_info_from_path(EmitChunk, Path) -> + BeamFiles = filelib:wildcard(filename:join(Path, "*.beam")), + + EmitChunk("{modules, [", []), + comma_separated_foreach(EmitChunk, + fun(Beam) -> + emit_module_info(EmitChunk, Beam) + end, BeamFiles), + EmitChunk("]}", []). + +emit_module_info(EmitChunk, Beam) -> + %% FIXME: The next three calls load *all* significant chunks onto the heap, + %% which may cause us to run out of memory if there's a huge module in the + %% code path. + {ok,{Mod, Md5}} = beam_lib:md5(Beam), + + CompilerVersion = get_compiler_version(Beam), + Native = beam_is_native_compiled(Beam), + + Loaded = case code:is_loaded(Mod) of + false -> false; + _ -> true + end, + + EmitChunk("{~p,[" + "{loaded,~p}," + "{native,~p}," + "{compiler,~p}," + "{md5,~p}" + "]}", + [Mod, Loaded, Native, CompilerVersion, hexstring(Md5)]). + +comma_separated_foreach(_EmitChunk, _Fun, []) -> + ok; +comma_separated_foreach(_EmitChunk, Fun, [H]) -> + Fun(H); +comma_separated_foreach(EmitChunk, Fun, [H | T]) -> + Fun(H), + EmitChunk(",", []), + comma_separated_foreach(EmitChunk, Fun, T). + is_application_path(Path) -> case filelib:wildcard(filename:join(Path, "*.app")) of [] -> false; _ -> true end. -get_application_from_path(Path) -> - [Appfile|_] = filelib:wildcard(filename:join(Path, "*.app")), - case file:consult(Appfile) of - {ok, [{application, App, Info}]} -> - {App, [ - {description, proplists:get_value(description, Info, [])}, - {vsn, proplists:get_value(vsn, Info, [])}, - {path, Path}, - {runtime_dependencies, - proplists:get_value(runtime_dependencies, Info, [])}, - {modules, get_modules_from_path(Path)} - ]} - end. - -get_modules_from_path(Path) -> - [ - begin - {ok,{Mod, Md5}} = beam_lib:md5(Beam), - Loaded = case code:is_loaded(Mod) of - false -> false; - _ -> true - end, - {Mod, [ - {loaded, Loaded}, - {native, beam_is_native_compiled(Beam)}, - {compiler, get_compiler_version(Beam)}, - {md5, hexstring(Md5)} - ]} - end || Beam <- filelib:wildcard(filename:join(Path, "*.beam")) - ]. - hexstring(Bin) when is_binary(Bin) -> lists:flatten([io_lib:format("~2.16.0b", [V]) || <> <= Bin]). -- cgit v1.2.3