Merge branch 'hans/ssh/optimize_sftp_window_handling/OTP-13130' into maint

* hans/ssh/optimize_sftp_window_handling/OTP-13130:
  ssh: sftpd callback takes new option 'recv_window_size', defaults to 1000000
  ssh: added 'pending' in recv_window handling and limit sending

3 files changed, 45 insertions, 7 deletions

diff --git a/lib/ssh/src/ssh_connect.hrl b/lib/ssh/src/ssh_connect.hrl
index 6db89c5d80..9f9f3de8fa 100644
--- a/lib/ssh/src/ssh_connect.hrl
+++ b/lib/ssh/src/ssh_connect.hrl
@@ -248,6 +248,9 @@
 	  local_id,           %% local channel id
 
 	  recv_window_size,
+	  recv_window_pending = 0, %% Sum of window size updates that has not
+	                           %% yet been sent. This limits the number
+	                           %% of sent update msgs.
 	  recv_packet_size,
 	  recv_close = false,
 
diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl
index 505c6eb181..68062209fc 100644
--- a/lib/ssh/src/ssh_connection_handler.erl
+++ b/lib/ssh/src/ssh_connection_handler.erl
@@ -731,13 +731,28 @@ handle_event({adjust_window, ChannelId, Bytes}, StateName,
 			#connection{channel_cache = Cache}} = State0) ->
     State =
 	case ssh_channel:cache_lookup(Cache, ChannelId) of
-	    #channel{recv_window_size = WinSize, remote_id = Id} = Channel ->
-		ssh_channel:cache_update(Cache, Channel#channel{recv_window_size =
-					       WinSize + Bytes}),
-		Msg = ssh_connection:channel_adjust_window_msg(Id, Bytes),
+	    #channel{recv_window_size = WinSize,
+		     recv_window_pending = Pending,
+		     recv_packet_size = PktSize} = Channel
+	      when (WinSize-Bytes) >= 2*PktSize ->
+		%% The peer can send at least two more *full* packet, no hurry.
+		ssh_channel:cache_update(Cache, 
+					 Channel#channel{recv_window_pending = Pending + Bytes}),
+		State0;
+
+	    #channel{recv_window_size = WinSize,
+		     recv_window_pending = Pending,
+		     remote_id = Id} = Channel ->
+		%% Now we have to update the window - we can't receive so many more pkts
+		ssh_channel:cache_update(Cache, 
+					 Channel#channel{recv_window_size =
+							     WinSize + Bytes + Pending,
+							 recv_window_pending = 0}),
+		Msg = ssh_connection:channel_adjust_window_msg(Id, Bytes + Pending),
 		send_replies([{connection_reply, Msg}], State0);
-	undefined ->
-	    State0
+
+	    undefined ->
+		State0
 	end,
     {next_state, StateName, next_packet(State)};
 
diff --git a/lib/ssh/src/ssh_sftpd.erl b/lib/ssh/src/ssh_sftpd.erl
index a6549f1c73..819cba697e 100644
--- a/lib/ssh/src/ssh_sftpd.erl
+++ b/lib/ssh/src/ssh_sftpd.erl
@@ -30,6 +30,7 @@
 
 -include("ssh.hrl").
 -include("ssh_xfer.hrl").
+-include("ssh_connect.hrl"). %% For ?DEFAULT_PACKET_SIZE and ?DEFAULT_WINDOW_SIZE
 
 %%--------------------------------------------------------------------
 %% External exports
@@ -47,6 +48,7 @@
 	  file_handler,			% atom() - callback module 
 	  file_state,                   % state for the file callback module
 	  max_files,                    % integer >= 0 max no files sent during READDIR
+	  options,			% from the subsystem declaration
 	  handles			% list of open handles
 	  %% handle is either {<int>, directory, {Path, unread|eof}} or
 	  %% {<int>, file, {Path, IoDevice}}
@@ -121,6 +123,7 @@ init(Options) ->
     MaxLength = proplists:get_value(max_files, Options, 0),
     Vsn = proplists:get_value(sftpd_vsn, Options, 5),
     {ok,  State#state{cwd = CWD, root = Root, max_files = MaxLength,
+		      options = Options,
 		      handles = [], pending = <<>>,
 		      xf = #ssh_xfer{vsn = Vsn, ext = []}}}.
 
@@ -164,7 +167,9 @@ handle_ssh_msg({ssh_cm, _, {exit_status, ChannelId, Status}}, State) ->
 %% Description: Handles other messages
 %%--------------------------------------------------------------------
 handle_msg({ssh_channel_up, ChannelId,  ConnectionManager}, 
-	   #state{xf =Xf} = State) ->
+	   #state{xf = Xf,
+		 options = Options} = State) ->
+    maybe_increase_recv_window(ConnectionManager,  ChannelId, Options),
     {ok,  State#state{xf = Xf#ssh_xfer{cm = ConnectionManager,
 				       channel = ChannelId}}}.
 
@@ -934,3 +939,18 @@ rename(Path, Path2, ReqId, State0) ->
     {Status, FS1} = FileMod:rename(Path, Path2, FS0),
     State1 = State0#state{file_state = FS1},
     send_status(Status, ReqId, State1).
+
+
+maybe_increase_recv_window(ConnectionManager, ChannelId, Options) ->
+    WantedRecvWindowSize = 
+	proplists:get_value(recv_window_size, Options, 1000000),
+    NumPkts = WantedRecvWindowSize div ?DEFAULT_PACKET_SIZE,
+    Increment = NumPkts*?DEFAULT_PACKET_SIZE - ?DEFAULT_WINDOW_SIZE,
+
+    if
+	Increment > 0 ->
+	    ssh_connection:adjust_window(ConnectionManager, ChannelId, 
+					 Increment);
+	Increment =< 0 ->
+	    do_nothing
+    end.