File 2836-Use-ets-lookup_element-when-possible.patch of Package erlang
From 05a6131d90da7a73e6529e72e5a6f5a7e715a54c Mon Sep 17 00:00:00 2001
From: Raimo Niskanen <raimo@erlang.org>
Date: Sun, 16 Feb 2020 01:24:50 +0100
Subject: [PATCH 6/6] Use ets:lookup_element when possible
Micro optimization to create less garbage from ets lookups
---
lib/kernel/src/inet_db.erl | 103 +++++++++++++++++++++++----------------------
1 file changed, 52 insertions(+), 51 deletions(-)
diff --git a/lib/kernel/src/inet_db.erl b/lib/kernel/src/inet_db.erl
index 491cb9c8d0..fbccc787a2 100644
--- a/lib/kernel/src/inet_db.erl
+++ b/lib/kernel/src/inet_db.erl
@@ -515,9 +515,8 @@ res_update(Option, TagTm) ->
end.
db_get(Name) ->
- case ets:lookup(inet_db, Name) of
- [] -> undefined;
- [{_,Val}] -> Val
+ try ets:lookup_element(inet_db, Name, 2)
+ catch error:badarg -> undefined
end.
add_rr(RR) ->
@@ -839,29 +838,31 @@ init([]) ->
cache_timer = init_timer() }}.
reset_db(Db) ->
- ets:insert(Db, {hostname, []}),
- ets:insert(Db, {res_ns, []}),
- ets:insert(Db, {res_alt_ns, []}),
- ets:insert(Db, {res_search, []}),
- ets:insert(Db, {res_domain, ""}),
- ets:insert(Db, {res_lookup, []}),
- ets:insert(Db, {res_recurse, true}),
- ets:insert(Db, {res_usevc, false}),
- ets:insert(Db, {res_id, 0}),
- ets:insert(Db, {res_retry, ?RES_RETRY}),
- ets:insert(Db, {res_timeout, ?RES_TIMEOUT}),
- ets:insert(Db, {res_inet6, false}),
- ets:insert(Db, {res_edns, false}),
- ets:insert(Db, {res_udp_payload_size, ?DNS_UDP_PAYLOAD_SIZE}),
- ets:insert(Db, {cache_size, ?CACHE_LIMIT}),
- ets:insert(Db, {cache_refresh_interval,?CACHE_REFRESH}),
- ets:insert(Db, {socks5_server, ""}),
- ets:insert(Db, {socks5_port, ?IPPORT_SOCKS}),
- ets:insert(Db, {socks5_methods, [none]}),
- ets:insert(Db, {socks5_noproxy, []}),
- ets:insert(Db, {tcp_module, ?DEFAULT_TCP_MODULE}),
- ets:insert(Db, {udp_module, ?DEFAULT_UDP_MODULE}),
- ets:insert(Db, {sctp_module, ?DEFAULT_SCTP_MODULE}).
+ ets:insert(
+ Db,
+ [{hostname, []},
+ {res_ns, []},
+ {res_alt_ns, []},
+ {res_search, []},
+ {res_domain, ""},
+ {res_lookup, []},
+ {res_recurse, true},
+ {res_usevc, false},
+ {res_id, 0},
+ {res_retry, ?RES_RETRY},
+ {res_timeout, ?RES_TIMEOUT},
+ {res_inet6, false},
+ {res_edns, false},
+ {res_udp_payload_size, ?DNS_UDP_PAYLOAD_SIZE},
+ {cache_size, ?CACHE_LIMIT},
+ {cache_refresh_interval,?CACHE_REFRESH},
+ {socks5_server, ""},
+ {socks5_port, ?IPPORT_SOCKS},
+ {socks5_methods, [none]},
+ {socks5_noproxy, []},
+ {tcp_module, ?DEFAULT_TCP_MODULE},
+ {udp_module, ?DEFAULT_UDP_MODULE},
+ {sctp_module, ?DEFAULT_SCTP_MODULE}]).
%%----------------------------------------------------------------------
%% Func: handle_call/3
@@ -925,7 +926,7 @@ handle_call(Request, From, #state{db=Db}=State) ->
case res_check_option(Opt, El) of
true ->
Optname = res_optname(Opt),
- [{_,Es}] = ets:lookup(Db, Optname),
+ Es = ets:lookup_element(Db, Optname, 2),
NewEs = case Op of
ins -> [E | lists_delete(E, Es)];
add -> lists_delete(E, Es) ++ El;
@@ -1031,13 +1032,13 @@ handle_call(Request, From, #state{db=Db}=State) ->
{reply, ok, State};
{add_socks_methods, Ls} ->
- [{_,As}] = ets:lookup(Db, socks5_methods),
+ As = ets:lookup_element(Db, socks5_methods, 2),
As1 = lists_subtract(As, Ls),
ets:insert(Db, {socks5_methods, As1 ++ Ls}),
{reply, ok, State};
{del_socks_methods, Ls} ->
- [{_,As}] = ets:lookup(Db, socks5_methods),
+ As = ets:lookup_element(Db, socks5_methods, 2),
As1 = lists_subtract(As, Ls),
case lists:member(none, As1) of
false -> ets:insert(Db, {socks5_methods, As1 ++ [none]});
@@ -1051,12 +1052,12 @@ handle_call(Request, From, #state{db=Db}=State) ->
{add_socks_noproxy, {{A,B,C,D},{MA,MB,MC,MD}}}
when ?ip(A,B,C,D), ?ip(MA,MB,MC,MD) ->
- [{_,As}] = ets:lookup(Db, socks5_noproxy),
+ As = ets:lookup_element(Db, socks5_noproxy, 2),
ets:insert(Db, {socks5_noproxy, As++[{{A,B,C,D},{MA,MB,MC,MD}}]}),
{reply, ok, State};
{del_socks_noproxy, {A,B,C,D}=IP} when ?ip(A,B,C,D) ->
- [{_,As}] = ets:lookup(Db, socks5_noproxy),
+ As = ets:lookup_element(Db, socks5_noproxy, 2),
ets:insert(Db, {socks5_noproxy, lists_keydelete(IP, 1, As)}),
{reply, ok, State};
@@ -1156,19 +1157,19 @@ handle_set_file(
%%
%% Maybe update file content
%%
- case ets:lookup(Db, TagTm) of
- [] ->
- %% Option no longer set - ignore update
- {reply, ok, State};
- [{_, Tm}] ->
+ try ets:lookup_element(Db, TagTm, 2) of
+ Tm ->
%% Current update request
- [{_, File}] = ets:lookup(Db, res_optname(Option)),
- [{_, Finfo}] = ets:lookup(Db, TagInfo),
+ File = ets:lookup_element(Db, res_optname(Option), 2),
+ Finfo = ets:lookup_element(Db, TagInfo, 2),
handle_update_file(
Finfo, File, TagTm, TagInfo, ParseFun, From, State);
- [_] ->
+ _ ->
%% Late request - ignore update
{reply, ok, State}
+ catch error:badarg ->
+ %% Option no longer set - ignore update
+ {reply, ok, State}
end;
handle_set_file(
Option, Fname, TagTm, TagInfo, ParseFun, From, #state{db=Db}=State) ->
@@ -1237,8 +1238,8 @@ do_add_host(Byname, Byaddr, Names, Type, IP) ->
Nms = [tolower(Nm) || Nm <- Names],
add_ip_bynms(Byname, Type, IP, Nms, Names),
Key = {Type, IP},
- case ets:lookup(Byaddr, Key) of
- [{_Key, Names_0}] ->
+ try ets:lookup_element(Byaddr, Key, 2) of
+ Names_0 ->
%% Delete IP address from byname entries
NmsSet = % Set of new tolower(Name)s
lists:foldl(
@@ -1248,8 +1249,8 @@ do_add_host(Byname, Byaddr, Names, Type, IP) ->
del_ip_bynms(
Byname, Type, IP,
[Nm || Nm <- [tolower(Name) || Name <- Names_0],
- not maps:is_key(Nm, NmsSet)]);
- [] ->
+ not maps:is_key(Nm, NmsSet)])
+ catch error:badarg ->
ok
end,
%% Replace the entry in the byaddr table
@@ -1259,16 +1260,16 @@ do_add_host(Byname, Byaddr, Names, Type, IP) ->
do_del_host(Byname, Byaddr, IP) ->
Fam = inet_family(IP),
Key = {Fam, IP},
- case ets:lookup(Byaddr, Key) of
- [{_Key, Names}] ->
+ try ets:lookup_element(Byaddr, Key, 2) of
+ Names ->
%% Delete IP address from byname entries
del_ip_bynms(
Byname, Fam, IP,
[tolower(Name) || Name <- Names]),
%% Delete from byaddr table
true = ets:delete(Byaddr, Key),
- ok;
- [] ->
+ ok
+ catch error:badarg ->
ok
end.
@@ -1690,12 +1691,12 @@ do_refresh_cache(Key, CacheDb, Now, OldestT) ->
%% -------------------------------------------------------------------
alloc_entry(Db, CacheDb, TM) ->
CurSize = ets:info(CacheDb, size),
- case ets:lookup(Db, cache_size) of
- [{cache_size, Size}] when Size =< CurSize, Size > 0 ->
+ case ets:lookup_element(Db, cache_size, 2) of
+ Size when Size =< CurSize, Size > 0 ->
alloc_entry(CacheDb, CurSize, TM, trunc(Size * 0.1) + 1);
- [{cache_size, Size}] when Size =< 0 ->
+ Size when Size =< 0 ->
false;
- _ ->
+ _Size ->
true
end.
--
2.16.4
