drbd: use rolling marks for resync speed calculation

The current resync speed as displayed in /proc/drbd fluctuates a lot.
Using an array of rolling marks makes this calculation much more stable.
We used to have this (a long time ago with 0.7), but it got lost somehow.

If "stalled", do not discard the rest of the information, just add a
" (stalled)" tag to the progress line.

This patch also shortens a spinlock critical section somewhat, and
reduces the number of atomic operations in put_ldev.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

1 files changed, 20 insertions, 9 deletions

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index ed09a840d838..1ff8418ae0fa 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1064,7 +1064,8 @@ int __drbd_set_state(struct drbd_conf *mdev,
 	if ((os.conn == C_PAUSED_SYNC_T || os.conn == C_PAUSED_SYNC_S) &&
 	    (ns.conn == C_SYNC_TARGET  || ns.conn == C_SYNC_SOURCE)) {
 		dev_info(DEV, "Syncer continues.\n");
-		mdev->rs_paused += (long)jiffies-(long)mdev->rs_mark_time;
+		mdev->rs_paused += (long)jiffies
+				  -(long)mdev->rs_mark_time[mdev->rs_last_mark];
 		if (ns.conn == C_SYNC_TARGET) {
 			if (!test_and_clear_bit(STOP_SYNC_TIMER, &mdev->flags))
 				mod_timer(&mdev->resync_timer, jiffies);
@@ -1078,27 +1079,33 @@ int __drbd_set_state(struct drbd_conf *mdev,
 	if ((os.conn == C_SYNC_TARGET  || os.conn == C_SYNC_SOURCE) &&
 	    (ns.conn == C_PAUSED_SYNC_T || ns.conn == C_PAUSED_SYNC_S)) {
 		dev_info(DEV, "Resync suspended\n");
-		mdev->rs_mark_time = jiffies;
+		mdev->rs_mark_time[mdev->rs_last_mark] = jiffies;
 		if (ns.conn == C_PAUSED_SYNC_T)
 			set_bit(STOP_SYNC_TIMER, &mdev->flags);
 	}
 
 	if (os.conn == C_CONNECTED &&
 	    (ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T)) {
+		unsigned long now = jiffies;
+		int i;
+
 		mdev->ov_position = 0;
-		mdev->rs_total =
-		mdev->rs_mark_left = drbd_bm_bits(mdev);
+		mdev->rs_total = drbd_bm_bits(mdev);
 		if (mdev->agreed_pro_version >= 90)
 			set_ov_position(mdev, ns.conn);
 		else
 			mdev->ov_start_sector = 0;
 		mdev->ov_left = mdev->rs_total
 			      - BM_SECT_TO_BIT(mdev->ov_position);
-		mdev->rs_start     =
-		mdev->rs_mark_time = jiffies;
+		mdev->rs_start = now;
 		mdev->ov_last_oos_size = 0;
 		mdev->ov_last_oos_start = 0;
 
+		for (i = 0; i < DRBD_SYNC_MARKS; i++) {
+			mdev->rs_mark_left[i] = mdev->rs_total;
+			mdev->rs_mark_time[i] = now;
+		}
+
 		if (ns.conn == C_VERIFY_S) {
 			dev_info(DEV, "Starting Online Verify from sector %llu\n",
 					(unsigned long long)mdev->ov_position);
@@ -2793,6 +2800,7 @@ void drbd_init_set_defaults(struct drbd_conf *mdev)
 
 void drbd_mdev_cleanup(struct drbd_conf *mdev)
 {
+	int i;
 	if (mdev->receiver.t_state != None)
 		dev_err(DEV, "ASSERT FAILED: receiver t_state == %d expected 0.\n",
 				mdev->receiver.t_state);
@@ -2809,9 +2817,12 @@ void drbd_mdev_cleanup(struct drbd_conf *mdev)
 	mdev->p_size       =
 	mdev->rs_start     =
 	mdev->rs_total     =
-	mdev->rs_failed    =
-	mdev->rs_mark_left =
-	mdev->rs_mark_time = 0;
+	mdev->rs_failed    = 0;
+	mdev->rs_last_events = 0;
+	for (i = 0; i < DRBD_SYNC_MARKS; i++) {
+		mdev->rs_mark_left[i] = 0;
+		mdev->rs_mark_time[i] = 0;
+	}
 	D_ASSERT(mdev->net_conf == NULL);
 
 	drbd_set_my_capacity(mdev, 0);