File 2181-Remove-the-file_io_servers-ETS-table.patch of Package erlang

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File 2181-Remove-the-file_io_servers-ETS-table.patch of Package erlang (Revision c43d7e29f1118cfaa3ff5f8a1020d549)

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From 8ba186c2d3754a9fbc59de6fb5ce28538c1f2787 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Muska=C5=82a?= <micmus@fb.com>
Date: Thu, 19 Jan 2023 11:58:55 +0000
Subject: [PATCH] Remove the file_io_servers ETS table

This table was used to store Pids of files opened through the file server,
however this data was never used by OTP itself, except for the debugging
file:pid2file/1 function. Given the function is deprecated, we can skip the
overhead of the central ETS table, and store the name in the file process
itself. This makes the pid2file function more expensive, but as a deprecated
debugging facility this is acceptable given reduction in overall
memory overhead and synchronisation.
---
 lib/kernel/src/file.erl                  | 13 +++----------
 lib/kernel/src/file_io_server.erl        | 12 ++++++++----
 lib/kernel/src/file_server.erl           | 15 ++-------------
 lib/kernel/test/file_SUITE.erl           |  4 ++--
 lib/stdlib/test/error_logger_h_SUITE.erl | 22 +++++++++++-----------
 5 files changed, 26 insertions(+), 40 deletions(-)

diff --git a/lib/kernel/src/file.erl b/lib/kernel/src/file.erl
index 9e5d3fcfbe..e2ed6ef1dc 100644
--- a/lib/kernel/src/file.erl
+++ b/lib/kernel/src/file.erl
@@ -173,16 +173,9 @@ format_error(ErrorId) ->
       Pid :: pid().
 
 pid2name(Pid) when is_pid(Pid) ->
-    case whereis(?FILE_SERVER) of
-	undefined ->
-	    undefined;
-	_ ->
-	    case ets:lookup(?FILE_IO_SERVER_TABLE, Pid) of
-		[{_, Name} | _] ->
-		    {ok, Name};
-		_ ->
-		    undefined
-	    end
+    case file_request(Pid, pid2name) of
+        {ok, _} = Ok -> Ok;
+        _ -> undefined
     end.
 
 %%%-----------------------------------------------------------------
diff --git a/lib/kernel/src/file_io_server.erl b/lib/kernel/src/file_io_server.erl
index 723325bdfb..a85eff1b20 100644
--- a/lib/kernel/src/file_io_server.erl
+++ b/lib/kernel/src/file_io_server.erl
@@ -26,7 +26,7 @@
 
 -export([count_and_find/3]).
 
--record(state, {handle,owner,mref,buf,read_mode,unic}).
+-record(state, {handle,owner,mref,name,buf,read_mode,unic}).
 
 -include("file_int.hrl").
 
@@ -80,8 +80,9 @@ do_start(Spawn, Owner, FileName, ModeList) ->
 				  Self ! {Ref, ok},
 				  server_loop(
 				    #state{handle    = Handle,
-					   owner     = Owner, 
-					   mref      = M, 
+					   owner     = Owner,
+					   mref      = M,
+					   name      = FileName,
 					   buf       = <<>>,
 					   read_mode = ReadMode,
 					   unic = UnicodeMode})
@@ -322,7 +323,10 @@ file_request({read_handle_info, Opts},
         Reply ->
             {reply,Reply,State}
     end;
-file_request(Unknown, 
+file_request(pid2name,
+             #state{name=Name}=State) ->
+    {reply,{ok,Name},State};
+file_request(Unknown,
 	     #state{}=State) ->
     Reason = {request, Unknown},
     {error,{error,Reason},State}.
diff --git a/lib/kernel/src/file_server.erl b/lib/kernel/src/file_server.erl
index 29eaa23375..12e187902b 100644
--- a/lib/kernel/src/file_server.erl
+++ b/lib/kernel/src/file_server.erl
@@ -37,8 +37,6 @@
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2, 
 	 terminate/2, code_change/3]).
 
--define(FILE_IO_SERVER_TABLE, file_io_servers).
-
 -define(FILE_SERVER, file_server_2).      % Registered name
 -define(FILE_IO_SERVER, file_io_server).  % Module
 -define(PRIM_FILE, prim_file).            % Module
@@ -56,7 +54,7 @@ format_error(ErrorId) ->
 start() -> do_start(start).
 start_link() -> do_start(start_link).
 
-stop() -> 
+stop() ->
     gen_server:call(?FILE_SERVER, stop, infinity).
 
 %%%----------------------------------------------------------------------
@@ -77,7 +75,6 @@ stop() ->
 
 init([]) ->
     process_flag(trap_exit, true),
-    ?FILE_IO_SERVER_TABLE =  ets:new(?FILE_IO_SERVER_TABLE, [named_table]),
     {ok, undefined}.
 
 %%----------------------------------------------------------------------
@@ -97,14 +94,7 @@ init([]) ->
 
 handle_call({open, Name, ModeList}, {Pid, _Tag} = _From, State)
   when is_list(ModeList) ->
-    Child = ?FILE_IO_SERVER:start_link(Pid, Name, ModeList),
-    case Child of
-	{ok, P} when is_pid(P) ->
-	    ets:insert(?FILE_IO_SERVER_TABLE, {P, Name});
-	_ ->
-	    ok
-    end,
-    {reply, Child, State};
+    {reply, ?FILE_IO_SERVER:start_link(Pid, Name, ModeList), State};
 
 handle_call({open, _Name, _Mode}, _From, State) ->
     {reply, {error, einval}, State};
@@ -228,7 +218,6 @@ handle_cast(Msg, State) ->
         {'noreply', state()}.
 
 handle_info({'EXIT', Pid, _Reason}, State) when is_pid(Pid) ->
-    ets:delete(?FILE_IO_SERVER_TABLE, Pid),
     {noreply, State};
 
 handle_info(Info, State) ->
diff --git a/lib/kernel/test/file_SUITE.erl b/lib/kernel/test/file_SUITE.erl
index b791a577f0..aeee1ee8ac 100644
--- a/lib/kernel/test/file_SUITE.erl
+++ b/lib/kernel/test/file_SUITE.erl
@@ -3451,9 +3451,9 @@ pid2name(Config) when is_list(Config) ->
     %%
     {ok, Pid} = file:open(Name1, [write]),
     {ok, Name2} = file:pid2name(Pid),
-    undefined = file:pid2name(self()),
+    Dead = spawn(fun() -> ok end),
+    undefined = file:pid2name(Dead),
     ok = file:close(Pid),
-    ct:sleep(1000),
     false = is_process_alive(Pid),
     undefined = file:pid2name(Pid),
     ok.
diff --git a/lib/stdlib/test/error_logger_h_SUITE.erl b/lib/stdlib/test/error_logger_h_SUITE.erl
index d1f375459b..0fde51b146 100644
--- a/lib/stdlib/test/error_logger_h_SUITE.erl
+++ b/lib/stdlib/test/error_logger_h_SUITE.erl
@@ -67,17 +67,17 @@ logfile(Config) ->
     analyse_events(Log, Ev, [AtNode], unlimited),
 
     %% Make sure that the file_io_server process has been stopped
-    [] = lists:filtermap(
-           fun(X) ->
-                   case {process_info(X, [current_function]),
-                         file:pid2name(X)} of
-                       {[{current_function, {file_io_server, _, _}}],
-                        {ok,P2N = Log}} ->
-                           {true, {X, P2N}};
-                       _ ->
-                           false
-                   end
-           end, processes()),
+    [] = lists:filtermap(fun(X) ->
+        case process_info(X, [current_function]) of
+            [{current_function, {file_io_server, _, _}}] ->
+                case file:pid2name(X) of
+                    {ok, Log} -> {true, {X, Log}};
+                    _ -> false
+                end;
+            _ ->
+                false
+        end
+    end, processes()),
 
     test_server:stop_node(Node),
 
-- 
2.35.3

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File 2181-Remove-the-file_io_servers-ETS-table.patch of Package erlang (Revision c43d7e29f1118cfaa3ff5f8a1020d549)

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