drbd: Four new configuration settings for resync speed control

To reasonably control resync speed over drbd-proxy connections,
drbd has to measure the current delay of packets transmitted over
the (possibly congested) data socket vs the meta-data socket.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_nl.c

@@ -1555,6 +1555,10 @@ static int drbd_nl_syncer_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *n
 		sc.rate       = DRBD_RATE_DEF;
 		sc.after      = DRBD_AFTER_DEF;
 		sc.al_extents = DRBD_AL_EXTENTS_DEF;
+		sc.dp_volume  = DRBD_DP_VOLUME_DEF;
+		sc.dp_interval = DRBD_DP_INTERVAL_DEF;
+		sc.throttle_th = DRBD_RS_THROTTLE_TH_DEF;
+		sc.hold_off_th = DRBD_RS_HOLD_OFF_TH_DEF;
 	} else
 		memcpy(&sc, &mdev->sync_conf, sizeof(struct syncer_conf));
 

include/linux/drbd_limits.h

@@ -133,5 +133,21 @@
 #define DRBD_MAX_BIO_BVECS_MAX 128
 #define DRBD_MAX_BIO_BVECS_DEF 0
 
+#define DRBD_DP_VOLUME_MIN 4
+#define DRBD_DP_VOLUME_MAX 1048576
+#define DRBD_DP_VOLUME_DEF 16384
+
+#define DRBD_DP_INTERVAL_MIN 1
+#define DRBD_DP_INTERVAL_MAX 600
+#define DRBD_DP_INTERVAL_DEF 5
+
+#define DRBD_RS_THROTTLE_TH_MIN 1
+#define DRBD_RS_THROTTLE_TH_MAX 600
+#define DRBD_RS_THROTTLE_TH_DEF 20
+
+#define DRBD_RS_HOLD_OFF_TH_MIN 1
+#define DRBD_RS_HOLD_OFF_TH_MAX 6000
+#define DRBD_RS_HOLD_OFF_TH_DEF 100
+
 #undef RANGE
 #endif

include/linux/drbd_nl.h

@@ -78,6 +78,10 @@ NL_PACKET(syncer_conf, 8,
 	NL_INTEGER(	30,	T_MAY_IGNORE,	rate)
 	NL_INTEGER(	31,	T_MAY_IGNORE,	after)
 	NL_INTEGER(	32,	T_MAY_IGNORE,	al_extents)
+	NL_INTEGER(     71,	T_MAY_IGNORE,	dp_volume)
+	NL_INTEGER(     72,	T_MAY_IGNORE,	dp_interval)
+	NL_INTEGER(     73,	T_MAY_IGNORE,	throttle_th)
+	NL_INTEGER(     74,	T_MAY_IGNORE,	hold_off_th)
 	NL_STRING(      52,     T_MAY_IGNORE,   verify_alg,     SHARED_SECRET_MAX)
 	NL_STRING(      51,     T_MAY_IGNORE,   cpu_mask,       32)
 	NL_STRING(	64,	T_MAY_IGNORE,	csums_alg,	SHARED_SECRET_MAX)