From 123ff122ade4b22961f2c244c44966d52c2a7ca5 Mon Sep 17 00:00:00 2001 From: Lars Ellenberg Date: Wed, 5 Feb 2014 06:13:53 +0100 Subject: [PATCH] drbd: trigger tcp_push_pending_frames() for PING and PING_ACK This should reduce latency for such in-DRBD-protocol "pings", and may help reduce spurious disconnect/reconnect cycles due to "PingAck did not arrive in time." Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg --- drivers/block/drbd/drbd_main.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index 8e0813ddf72a..77d34a61bb58 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -662,6 +662,11 @@ static int __send_command(struct drbd_connection *connection, int vnr, msg_flags); if (data && !err) err = drbd_send_all(connection, sock->socket, data, size, 0); + /* DRBD protocol "pings" are latency critical. + * This is supposed to trigger tcp_push_pending_frames() */ + if (!err && (cmd == P_PING || cmd == P_PING_ACK)) + drbd_tcp_nodelay(sock->socket); + return err; }