memsup.erl

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%% ``The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved via the world wide web at http://www.erlang.org/.
%% 
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%% 
%% The Initial Developer of the Original Code is Ericsson Utvecklings AB.
%% Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
%% AB. All Rights Reserved.''
%% 
%%     $Id$
%%
-module(memsup).
-behaviour(gen_server).

%% API
-export([start_link/0]). % for supervisor
-export([get_memory_data/0, get_system_memory_data/0,
	 get_check_interval/0, set_check_interval/1,
	 get_procmem_high_watermark/0, set_procmem_high_watermark/1,
	 get_sysmem_high_watermark/0, set_sysmem_high_watermark/1,
	 get_helper_timeout/0, set_helper_timeout/1]).
-export([dummy_reply/1, param_type/2, param_default/1]).

%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
	 terminate/2, code_change/3]).

%% Other exports
-export([format_status/2]).

-include("memsup.hrl").

-record(state,
	{os,                  % {OSfamily,OSname} | OSfamily
	 port_mode,           % bool()

	 mem_usage,           % undefined | {Alloc, Total}
	 worst_mem_user,      % undefined | {Pid, Alloc}

	 sys_only,            % bool()  memsup_system_only
	 timeout,             % int()   memory_check_interval, ms
	 helper_timeout,      % int()   memsup_helper_timeout, ms
	 sys_mem_watermark,   % float() system_memory_high_watermark, %
	 proc_mem_watermark,  % float() process_memory_high_watermark, %

	 pid,                 % undefined | pid()
	 wd_timer,            % undefined | TimerRef
	 ext_wd_timer,        % undefined | TimerRef
	 pending = [],        % [reg | {reg,From} | {ext,From}]
	 ext_pending = []     % [{ext,From}]
	}).

%%----------------------------------------------------------------------
%% API
%%----------------------------------------------------------------------

start_link() ->
    gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).

get_memory_data() ->
    os_mon:call(memsup, get_memory_data, infinity).

get_system_memory_data() ->
    os_mon:call(memsup, get_system_memory_data, infinity).

get_check_interval() ->
    os_mon:call(memsup, get_check_interval, infinity).
set_check_interval(Minutes) ->
    case param_type(memory_check_interval, Minutes) of
	true ->
	    MS = minutes_to_ms(Minutes), % for backwards compatibility
	    os_mon:call(memsup, {set_check_interval, MS}, infinity);
	false ->
	    erlang:error(badarg)
    end.

get_procmem_high_watermark() ->
    os_mon:call(memsup, get_procmem_high_watermark, infinity).
set_procmem_high_watermark(Float) ->
    case param_type(process_memory_high_watermark, Float) of
	true ->
	    os_mon:call(memsup, {set_procmem_high_watermark, Float},
			infinity);
	false ->
	    erlang:error(badarg)
    end.

get_sysmem_high_watermark() ->
    os_mon:call(memsup, get_sysmem_high_watermark, infinity).
set_sysmem_high_watermark(Float) ->
    case param_type(system_memory_high_watermark, Float) of
	true ->
	    os_mon:call(memsup, {set_sysmem_high_watermark, Float},
			infinity);
	false ->
	    erlang:error(badarg)
    end.

get_helper_timeout() ->
    os_mon:call(memsup, get_helper_timeout, infinity).
set_helper_timeout(Seconds) ->
    case param_type(memsup_helper_timeout, Seconds) of
	true ->
	    os_mon:call(memsup, {set_helper_timeout, Seconds});
	false ->
	    erlang:error(badarg)
    end.

dummy_reply(get_memory_data) ->
    dummy_reply(get_memory_data,
		os_mon:get_env(memsup, memsup_system_only));
dummy_reply(get_system_memory_data) ->
    [];
dummy_reply(get_check_interval) ->
    minutes_to_ms(os_mon:get_env(memsup, memory_check_interval));
dummy_reply({set_check_interval, _}) ->
    ok;
dummy_reply(get_procmem_high_watermark) ->
    trunc(100 * os_mon:get_env(memsup, process_memory_high_watermark));
dummy_reply({set_procmem_high_watermark, _}) ->
    ok;
dummy_reply(get_sysmem_high_watermark) ->
    trunc(100 * os_mon:get_env(memsup, system_memory_high_watermark));
dummy_reply({set_sysmem_high_watermark, _}) ->
    ok;
dummy_reply(get_helper_timeout) ->
    os_mon:get_env(memsup, memsup_helper_timeout);
dummy_reply({set_helper_timeout, _}) ->
    ok.
dummy_reply(get_memory_data, true) ->
    {0,0,undefined};
dummy_reply(get_memory_data, false) ->
    {0,0,{self(),0}}.

param_type(memsup_system_only, Val) when Val==true; Val==false -> true;
param_type(memory_check_interval, Val) when is_integer(Val),
                                            Val>0 -> true;
param_type(memsup_helper_timeout, Val) when is_integer(Val),
                                            Val>0 -> true;
param_type(system_memory_high_watermark, Val) when is_number(Val),
						   0=<Val,
						   Val=<1 -> true;
param_type(process_memory_high_watermark, Val) when is_number(Val),
						    0=<Val,
						    Val=<1 -> true;
param_type(_Param, _Val) -> false.

param_default(memsup_system_only) -> false;
param_default(memory_check_interval) -> 1;
param_default(memsup_helper_timeout) -> 30;
param_default(system_memory_high_watermark) -> 0.80;
param_default(process_memory_high_watermark) -> 0.05.

%%----------------------------------------------------------------------
%% gen_server callbacks
%%----------------------------------------------------------------------

init([]) ->
    process_flag(trap_exit, true),
    process_flag(priority, low),

    OS = os:type(),
    PortMode = case OS of
		   {unix, darwin} -> false;
		   {unix, freebsd} -> false;
		   {unix, linux} -> false;
		   {unix, openbsd} -> true;
		   {unix, irix64} -> true;
		   {unix, irix} -> true;
		   {unix, sunos} -> true;
		   {win32, _OSname} -> false;
		   vxworks -> true;
		   _ ->
		       exit({unsupported_os, OS})
	       end,
    Pid = if
	      PortMode ->
		  spawn_link(fun() -> port_init() end);
	      not PortMode ->
		  undefined
	  end,

    %% Read the values of some configuration parameters
    SysOnly = os_mon:get_env(memsup, memsup_system_only),
    Timeout = os_mon:get_env(memsup, memory_check_interval),
    HelperTimeout = os_mon:get_env(memsup, memsup_helper_timeout),
    SysMem = os_mon:get_env(memsup, system_memory_high_watermark),
    ProcMem = os_mon:get_env(memsup, process_memory_high_watermark),

    %% Initiate first data collection
    self() ! time_to_collect,

    {ok, #state{os=OS, port_mode=PortMode,

		sys_only           = SysOnly,
		timeout            = minutes_to_ms(Timeout),
		helper_timeout     = sec_to_ms(HelperTimeout),
		sys_mem_watermark  = SysMem,
		proc_mem_watermark = ProcMem,

		pid=Pid}}.

handle_call(get_memory_data, From, State) ->
    %% Return result of latest memory check
    case State#state.mem_usage of
	{Alloc, Total} ->
	    Worst = State#state.worst_mem_user,
	    {reply, {Total, Alloc, Worst}, State};
	
	%% Special case: get_memory_data called before any memory data
	%% has been collected
	undefined ->
	    case State#state.wd_timer of
		undefined ->
		    WDTimer = erlang:send_after(State#state.timeout,
						self(),
						reg_collection_timeout),
		    Pending = [{reg,From}],
		    if
			State#state.port_mode ->
			    State#state.pid ! {self(), collect_sys},
			    {noreply, State#state{wd_timer=WDTimer,
						  pending=Pending}};
			true ->
			    OS = State#state.os,
			    Self = self(),
			    Pid = spawn_link(fun() ->
						     MU = get_memory_usage(OS),
						     Self ! {collected_sys,MU}
					     end),
			    {noreply, State#state{pid=Pid,
						  wd_timer=WDTimer,
						  pending=Pending}}
		    end;
		_TimerRef ->
		    Pending = [{reg,From} | State#state.pending],
		    {noreply, State#state{pending=Pending}}
	    end
    end;

handle_call(get_system_memory_data,From,#state{port_mode=true}=State) ->
    %% When using a port, the extensive memory collection is slightly
    %% different than a regular one
    case State#state.ext_wd_timer of
	undefined ->
	    WDTimer = erlang:send_after(State#state.helper_timeout,
					self(),
					ext_collection_timeout),
	    State#state.pid ! {self(), collect_ext_sys},
	    {noreply, State#state{ext_wd_timer=WDTimer,
				  ext_pending=[{ext,From}]}};
	_TimerRef ->
	    Pending = [{ext,From} | State#state.ext_pending],
	    {noreply, State#state{ext_pending=Pending}}
    end;
handle_call(get_system_memory_data, From, State) ->
    %% When not using a port, the regular memory collection is used
    %% for extensive memory data as well
    case State#state.wd_timer of
	undefined ->
	    WDTimer = erlang:send_after(State#state.helper_timeout,
					self(),
					reg_collection_timeout),
	    OS = State#state.os,
	    Self = self(),
	    Pid = spawn_link(fun() ->
				     MemUsage = get_memory_usage(OS),
				     Self ! {collected_sys, MemUsage}
			     end),
	    {noreply, State#state{pid=Pid, wd_timer=WDTimer,
				  pending=[{ext,From}]}};
	_TimerRef ->
	    Pending = [{ext,From} | State#state.pending],
	    {noreply, State#state{pending=Pending}}
    end;

handle_call(get_check_interval, _From, State) ->
    {reply, State#state.timeout, State};
handle_call({set_check_interval, MS}, _From, State) ->
    {reply, ok, State#state{timeout=MS}};

handle_call(get_procmem_high_watermark, _From, State) ->
    {reply, trunc(100 * State#state.proc_mem_watermark), State};
handle_call({set_procmem_high_watermark, Float}, _From, State) ->
    {reply, ok, State#state{proc_mem_watermark=Float}};

handle_call(get_sysmem_high_watermark, _From, State) ->
    {reply, trunc(100 * State#state.sys_mem_watermark), State};
handle_call({set_sysmem_high_watermark, Float}, _From, State) ->
    {reply, ok, State#state{sys_mem_watermark=Float}};

handle_call(get_helper_timeout, _From, State) ->
    {reply, ms_to_sec(State#state.helper_timeout), State};
handle_call({set_helper_timeout, Seconds}, _From, State) ->
    {reply, ok, State#state{helper_timeout=sec_to_ms(Seconds)}};

%% The following are only for test purposes (whitebox testing).
handle_call({set_sys_hw, HW}, _From, State) ->
    {reply, ok, State#state{sys_mem_watermark=HW}};
handle_call({set_pid_hw, HW}, _From, State) ->
    {reply, ok, State#state{proc_mem_watermark=HW}};
handle_call(get_state, _From, State) ->
    {reply, State, State}.

handle_cast(_Msg, State) ->
    {noreply, State}.

%% It's time to check memory
handle_info(time_to_collect, State) ->
    case State#state.wd_timer of
	undefined ->
	    WDTimer = erlang:send_after(State#state.helper_timeout,
					self(),
					reg_collection_timeout),
	    if
		State#state.port_mode ->
		    State#state.pid ! {self(), collect_sys},
		    {noreply, State#state{wd_timer=WDTimer,
					  pending=[reg]}};
		true ->
		    OS = State#state.os,
		    Self = self(),
		    Pid = spawn_link(fun() ->
					     MU = get_memory_usage(OS),
					     Self ! {collected_sys,MU}
				     end),
		    {noreply, State#state{pid=Pid, wd_timer=WDTimer,
					  pending=[reg]}}
	    end;