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-rw-r--r--lib/kernel/doc/src/file.xml19
-rw-r--r--lib/kernel/src/file.erl16
-rw-r--r--lib/kernel/src/file_io_server.erl8
-rw-r--r--lib/kernel/src/ram_file.erl33
-rw-r--r--lib/kernel/test/file_SUITE.erl77
-rw-r--r--lib/kernel/test/prim_file_SUITE.erl75
6 files changed, 224 insertions, 4 deletions
diff --git a/lib/kernel/doc/src/file.xml b/lib/kernel/doc/src/file.xml
index c94df62d1f..382262d1ee 100644
--- a/lib/kernel/doc/src/file.xml
+++ b/lib/kernel/doc/src/file.xml
@@ -62,6 +62,25 @@ time() = {{Year, Month, Day}, {Hour, Minute, Second}}
</section>
<funcs>
<func>
+ <name>advise(IoDevice, Offset, Length, Advise) -> ok | {error, Reason}</name>
+ <fsummary>Predeclare an access pattern for file data</fsummary>
+ <type>
+ <v>IoDevice = io_device()</v>
+ <v>Offset = int()</v>
+ <v>Length = int()</v>
+ <v>Advise = posix_file_advise()</v>
+ <v>posix_file_advise() = normal | sequential | random | no_reuse
+ | will_need | dont_need</v>
+ <v>Reason = ext_posix()</v>
+ </type>
+ <desc>
+ <p><c>advise/4</c> can be used to announce an intention to access file
+ data in a specific pattern in the future, thus allowing the
+ operating system to perform appropriate optimizations.</p>
+ <p>On some platforms, this function might have no effect.</p>
+ </desc>
+ </func>
+ <func>
<name>change_group(Filename, Gid) -> ok | {error, Reason}</name>
<fsummary>Change group of a file</fsummary>
<type>
diff --git a/lib/kernel/src/file.erl b/lib/kernel/src/file.erl
index 5da359fdf1..a694ed0708 100644
--- a/lib/kernel/src/file.erl
+++ b/lib/kernel/src/file.erl
@@ -36,7 +36,7 @@
%% Specialized
-export([ipread_s32bu_p32bu/3]).
%% Generic file contents.
--export([open/2, close/1,
+-export([open/2, close/1, advise/4,
read/2, write/2,
pread/2, pread/3, pwrite/2, pwrite/3,
read_line/1,
@@ -89,6 +89,8 @@
-type date() :: {pos_integer(), pos_integer(), pos_integer()}.
-type time() :: {non_neg_integer(), non_neg_integer(), non_neg_integer()}.
-type date_time() :: {date(), time()}.
+-type posix_file_advise() :: 'normal' | 'sequential' | 'random' | 'no_reuse' |
+ 'will_need' | 'dont_need'.
%%%-----------------------------------------------------------------
%%% General functions
@@ -352,6 +354,18 @@ close(#file_descriptor{module = Module} = Handle) ->
close(_) ->
{error, badarg}.
+-spec advise(File :: io_device(), Offset :: integer(),
+ Length :: integer(), Advise :: posix_file_advise()) ->
+ 'ok' | {'error', posix()}.
+
+advise(File, Offset, Length, Advise) when is_pid(File) ->
+ R = file_request(File, {advise, Offset, Length, Advise}),
+ wait_file_reply(File, R);
+advise(#file_descriptor{module = Module} = Handle, Offset, Length, Advise) ->
+ Module:advise(Handle, Offset, Length, Advise);
+advise(_, _, _, _) ->
+ {error, badarg}.
+
-spec read(File :: io_device(), Size :: non_neg_integer()) ->
'eof' | {'ok', [char()] | binary()} | {'error', posix()}.
diff --git a/lib/kernel/src/file_io_server.erl b/lib/kernel/src/file_io_server.erl
index d0b30192b3..39dc32bb79 100644
--- a/lib/kernel/src/file_io_server.erl
+++ b/lib/kernel/src/file_io_server.erl
@@ -198,6 +198,14 @@ io_reply(From, ReplyAs, Reply) ->
%%%-----------------------------------------------------------------
%%% file requests
+file_request({advise,Offset,Length,Advise},
+ #state{handle=Handle}=State) ->
+ case ?PRIM_FILE:advise(Handle, Offset, Length, Advise) of
+ {error,_}=Reply ->
+ {stop,normal,Reply,State};
+ Reply ->
+ {reply,Reply,State}
+ end;
file_request({pread,At,Sz},
#state{handle=Handle,buf=Buf,read_mode=ReadMode}=State) ->
case position(Handle, At, Buf) of
diff --git a/lib/kernel/src/ram_file.erl b/lib/kernel/src/ram_file.erl
index 0230cb4e0a..2bfb2cd021 100644
--- a/lib/kernel/src/ram_file.erl
+++ b/lib/kernel/src/ram_file.erl
@@ -28,7 +28,7 @@
%% Specialized file operations
-export([get_size/1, get_file/1, set_file/2, get_file_close/1]).
--export([compress/1, uncompress/1, uuencode/1, uudecode/1]).
+-export([compress/1, uncompress/1, uuencode/1, uudecode/1, advise/4]).
-export([open_mode/1]). %% used by ftp-file
@@ -71,6 +71,7 @@
-define(RAM_FILE_UUENCODE, 35).
-define(RAM_FILE_UUDECODE, 36).
-define(RAM_FILE_SIZE, 37).
+-define(RAM_FILE_ADVISE, 38).
%% Open modes for RAM_FILE_OPEN
-define(RAM_FILE_MODE_READ, 1).
@@ -91,6 +92,14 @@
-define(RAM_FILE_RESP_NUMBER, 3).
-define(RAM_FILE_RESP_INFO, 4).
+%% POSIX file advises
+-define(POSIX_FADV_NORMAL, 0).
+-define(POSIX_FADV_RANDOM, 1).
+-define(POSIX_FADV_SEQUENTIAL, 2).
+-define(POSIX_FADV_WILLNEED, 3).
+-define(POSIX_FADV_DONTNEED, 4).
+-define(POSIX_FADV_NOREUSE, 5).
+
%% --------------------------------------------------------------------------
%% Generic file contents operations.
%%
@@ -352,6 +361,28 @@ uudecode(#file_descriptor{module = ?MODULE, data = Port}) ->
uudecode(#file_descriptor{}) ->
{error, enotsup}.
+advise(#file_descriptor{module = ?MODULE, data = Port}, Offset,
+ Length, Advise) ->
+ Cmd0 = <<?RAM_FILE_ADVISE, Offset:64/signed, Length:64/signed>>,
+ case Advise of
+ normal ->
+ call_port(Port, <<Cmd0/binary, ?POSIX_FADV_NORMAL:32/signed>>);
+ random ->
+ call_port(Port, <<Cmd0/binary, ?POSIX_FADV_RANDOM:32/signed>>);
+ sequential ->
+ call_port(Port, <<Cmd0/binary, ?POSIX_FADV_SEQUENTIAL:32/signed>>);
+ will_need ->
+ call_port(Port, <<Cmd0/binary, ?POSIX_FADV_WILLNEED:32/signed>>);
+ dont_need ->
+ call_port(Port, <<Cmd0/binary, ?POSIX_FADV_DONTNEED:32/signed>>);
+ no_reuse ->
+ call_port(Port, <<Cmd0/binary, ?POSIX_FADV_NOREUSE:32/signed>>);
+ _ ->
+ {error, einval}
+ end;
+advise(#file_descriptor{}, _Offset, _Length, _Advise) ->
+ {error, enotsup}.
+
%%%-----------------------------------------------------------------
diff --git a/lib/kernel/test/file_SUITE.erl b/lib/kernel/test/file_SUITE.erl
index 2e6c3aba16..1d652679b0 100644
--- a/lib/kernel/test/file_SUITE.erl
+++ b/lib/kernel/test/file_SUITE.erl
@@ -82,6 +82,8 @@
-export([read_line_1/1, read_line_2/1, read_line_3/1,read_line_4/1]).
+-export([advise/1]).
+
%% Debug exports
-export([create_file_slow/2, create_file/2, create_bin/2]).
-export([verify_file/2, verify_bin/3]).
@@ -377,7 +379,9 @@ win_cur_dir_1(_Config) ->
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-files(suite) -> [open,pos,file_info,consult,eval,script,truncate,sync,datasync].
+files(suite) ->
+ [open,pos,file_info,consult,eval,script,truncate,
+ sync,datasync,advise].
open(suite) -> [open1,old_modes,new_modes,path_open,close,access,read_write,
pread_write,append,open_errors].
@@ -1402,6 +1406,77 @@ sync(Config) when is_list(Config) ->
?line test_server:timetrap_cancel(Dog),
ok.
+advise(suite) -> [];
+advise(doc) -> "Tests that ?FILE_MODULE:advise/4 at least doesn't crash.";
+advise(Config) when is_list(Config) ->
+ ?line Dog = test_server:timetrap(test_server:seconds(5)),
+ ?line PrivDir = ?config(priv_dir, Config),
+ ?line Advise = filename:join(PrivDir,
+ atom_to_list(?MODULE)
+ ++"_advise.fil"),
+
+ Line1 = "Hello\n",
+ Line2 = "World!\n",
+
+ ?line {ok, Fd} = ?FILE_MODULE:open(Advise, [write]),
+ ?line ok = ?FILE_MODULE:advise(Fd, 0, 0, normal),
+ ?line ok = io:format(Fd, "~s", [Line1]),
+ ?line ok = io:format(Fd, "~s", [Line2]),
+ ?line ok = ?FILE_MODULE:close(Fd),
+
+ ?line {ok, Fd2} = ?FILE_MODULE:open(Advise, [write]),
+ ?line ok = ?FILE_MODULE:advise(Fd2, 0, 0, random),
+ ?line ok = io:format(Fd2, "~s", [Line1]),
+ ?line ok = io:format(Fd2, "~s", [Line2]),
+ ?line ok = ?FILE_MODULE:close(Fd2),
+
+ ?line {ok, Fd3} = ?FILE_MODULE:open(Advise, [write]),
+ ?line ok = ?FILE_MODULE:advise(Fd3, 0, 0, sequential),
+ ?line ok = io:format(Fd3, "~s", [Line1]),
+ ?line ok = io:format(Fd3, "~s", [Line2]),
+ ?line ok = ?FILE_MODULE:close(Fd3),
+
+ ?line {ok, Fd4} = ?FILE_MODULE:open(Advise, [write]),
+ ?line ok = ?FILE_MODULE:advise(Fd4, 0, 0, will_need),
+ ?line ok = io:format(Fd4, "~s", [Line1]),
+ ?line ok = io:format(Fd4, "~s", [Line2]),
+ ?line ok = ?FILE_MODULE:close(Fd4),
+
+ ?line {ok, Fd5} = ?FILE_MODULE:open(Advise, [write]),
+ ?line ok = ?FILE_MODULE:advise(Fd5, 0, 0, dont_need),
+ ?line ok = io:format(Fd5, "~s", [Line1]),
+ ?line ok = io:format(Fd5, "~s", [Line2]),
+ ?line ok = ?FILE_MODULE:close(Fd5),
+
+ ?line {ok, Fd6} = ?FILE_MODULE:open(Advise, [write]),
+ ?line ok = ?FILE_MODULE:advise(Fd6, 0, 0, no_reuse),
+ ?line ok = io:format(Fd6, "~s", [Line1]),
+ ?line ok = io:format(Fd6, "~s", [Line2]),
+ ?line ok = ?FILE_MODULE:close(Fd6),
+
+ ?line {ok, Fd7} = ?FILE_MODULE:open(Advise, [write]),
+ ?line {error, einval} = ?FILE_MODULE:advise(Fd7, 0, 0, bad_advise),
+ ?line ok = ?FILE_MODULE:close(Fd7),
+
+ %% test write without advise, then a read after an advise
+ ?line {ok, Fd8} = ?FILE_MODULE:open(Advise, [write]),
+ ?line ok = io:format(Fd8, "~s", [Line1]),
+ ?line ok = io:format(Fd8, "~s", [Line2]),
+ ?line ok = ?FILE_MODULE:close(Fd8),
+ ?line {ok, Fd9} = ?FILE_MODULE:open(Advise, [read]),
+ Offset = 0,
+ %% same as a 0 length in some implementations
+ Length = length(Line1) + length(Line2),
+ ?line ok = ?FILE_MODULE:advise(Fd9, Offset, Length, sequential),
+ ?line {ok, Line1} = ?FILE_MODULE:read_line(Fd9),
+ ?line {ok, Line2} = ?FILE_MODULE:read_line(Fd9),
+ ?line eof = ?FILE_MODULE:read_line(Fd9),
+ ?line ok = ?FILE_MODULE:close(Fd9),
+
+ ?line [] = flush(),
+ ?line test_server:timetrap_cancel(Dog),
+ ok.
+
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
diff --git a/lib/kernel/test/prim_file_SUITE.erl b/lib/kernel/test/prim_file_SUITE.erl
index 842945e83c..21bdc06fdc 100644
--- a/lib/kernel/test/prim_file_SUITE.erl
+++ b/lib/kernel/test/prim_file_SUITE.erl
@@ -48,6 +48,8 @@
symlinks_a/1, symlinks_b/1,
list_dir_limit/1]).
+-export([advise/1]).
+
-include("test_server.hrl").
-include_lib("kernel/include/file.hrl").
@@ -380,7 +382,7 @@ win_cur_dir_1(_Config, Handle) ->
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-files(suite) -> [open,pos,file_info,truncate,sync,datasync].
+files(suite) -> [open,pos,file_info,truncate,sync,datasync,advise].
open(suite) -> [open1,modes,close,access,read_write,
pread_write,append].
@@ -1100,6 +1102,77 @@ sync(Config) when is_list(Config) ->
ok.
+advise(suite) -> [];
+advise(doc) -> "Tests that ?PRIM_FILE:advise/4 at least doesn't crash.";
+advise(Config) when is_list(Config) ->
+ ?line Dog = test_server:timetrap(test_server:seconds(5)),
+ ?line PrivDir = ?config(priv_dir, Config),
+ ?line Advise = filename:join(PrivDir,
+ atom_to_list(?MODULE)
+ ++"_advise.fil"),
+
+ Line1 = "Hello\n",
+ Line2 = "World!\n",
+
+ ?line {ok, Fd} = ?PRIM_FILE:open(Advise, [write]),
+ ?line ok = ?PRIM_FILE:advise(Fd, 0, 0, normal),
+ ?line ok = ?PRIM_FILE:write(Fd, Line1),
+ ?line ok = ?PRIM_FILE:write(Fd, Line2),
+ ?line ok = ?PRIM_FILE:close(Fd),
+
+ ?line {ok, Fd2} = ?PRIM_FILE:open(Advise, [write]),
+ ?line ok = ?PRIM_FILE:advise(Fd2, 0, 0, random),
+ ?line ok = ?PRIM_FILE:write(Fd2, Line1),
+ ?line ok = ?PRIM_FILE:write(Fd2, Line2),
+ ?line ok = ?PRIM_FILE:close(Fd2),
+
+ ?line {ok, Fd3} = ?PRIM_FILE:open(Advise, [write]),
+ ?line ok = ?PRIM_FILE:advise(Fd3, 0, 0, sequential),
+ ?line ok = ?PRIM_FILE:write(Fd3, Line1),
+ ?line ok = ?PRIM_FILE:write(Fd3, Line2),
+ ?line ok = ?PRIM_FILE:close(Fd3),
+
+ ?line {ok, Fd4} = ?PRIM_FILE:open(Advise, [write]),
+ ?line ok = ?PRIM_FILE:advise(Fd4, 0, 0, will_need),
+ ?line ok = ?PRIM_FILE:write(Fd4, Line1),
+ ?line ok = ?PRIM_FILE:write(Fd4, Line2),
+ ?line ok = ?PRIM_FILE:close(Fd4),
+
+ ?line {ok, Fd5} = ?PRIM_FILE:open(Advise, [write]),
+ ?line ok = ?PRIM_FILE:advise(Fd5, 0, 0, dont_need),
+ ?line ok = ?PRIM_FILE:write(Fd5, Line1),
+ ?line ok = ?PRIM_FILE:write(Fd5, Line2),
+ ?line ok = ?PRIM_FILE:close(Fd5),
+
+ ?line {ok, Fd6} = ?PRIM_FILE:open(Advise, [write]),
+ ?line ok = ?PRIM_FILE:advise(Fd6, 0, 0, no_reuse),
+ ?line ok = ?PRIM_FILE:write(Fd6, Line1),
+ ?line ok = ?PRIM_FILE:write(Fd6, Line2),
+ ?line ok = ?PRIM_FILE:close(Fd6),
+
+ ?line {ok, Fd7} = ?PRIM_FILE:open(Advise, [write]),
+ ?line {error, einval} = ?PRIM_FILE:advise(Fd7, 0, 0, bad_advise),
+ ?line ok = ?PRIM_FILE:close(Fd7),
+
+ %% test write without advise, then a read after an advise
+ ?line {ok, Fd8} = ?PRIM_FILE:open(Advise, [write]),
+ ?line ok = ?PRIM_FILE:write(Fd8, Line1),
+ ?line ok = ?PRIM_FILE:write(Fd8, Line2),
+ ?line ok = ?PRIM_FILE:close(Fd8),
+ ?line {ok, Fd9} = ?PRIM_FILE:open(Advise, [read]),
+ Offset = 0,
+ %% same as a 0 length in some implementations
+ Length = length(Line1) + length(Line2),
+ ?line ok = ?PRIM_FILE:advise(Fd9, Offset, Length, sequential),
+ ?line {ok, Line1} = ?PRIM_FILE:read_line(Fd9),
+ ?line {ok, Line2} = ?PRIM_FILE:read_line(Fd9),
+ ?line eof = ?PRIM_FILE:read_line(Fd9),
+ ?line ok = ?PRIM_FILE:close(Fd9),
+
+ ?line test_server:timetrap_cancel(Dog),
+ ok.
+
+
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
delete_a(suite) -> [];
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