drbd: Implemented priority inheritance for resync requests
We only issue resync requests if there is no significant application IO
going on. = Application IO has higher priority than resnyc IO.
If application IO can not be started because the resync process locked
an resync_lru entry, start the IO operations necessary to release the
lock ASAP.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 982d684..4008130 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -355,7 +355,7 @@
if (!get_ldev(mdev))
return -EIO;
- if (drbd_rs_should_slow_down(mdev))
+ if (drbd_rs_should_slow_down(mdev, sector))
goto defer;
/* GFP_TRY, because if there is no memory available right now, this may
@@ -503,16 +503,6 @@
number = SLEEP_TIME * mdev->c_sync_rate / ((BM_BLOCK_SIZE / 1024) * HZ);
}
- /* Throttle resync on lower level disk activity, which may also be
- * caused by application IO on Primary/SyncTarget.
- * Keep this after the call to drbd_rs_controller, as that assumes
- * to be called as precisely as possible every SLEEP_TIME,
- * and would be confused otherwise. */
- if (number && drbd_rs_should_slow_down(mdev)) {
- mdev->c_sync_rate = 1;
- number = 0;
- }
-
/* ignore the amount of pending requests, the resync controller should
* throttle down to incoming reply rate soon enough anyways. */
return number;
@@ -594,7 +584,8 @@
sector = BM_BIT_TO_SECT(bit);
- if (drbd_try_rs_begin_io(mdev, sector)) {
+ if (drbd_rs_should_slow_down(mdev, sector) ||
+ drbd_try_rs_begin_io(mdev, sector)) {
mdev->bm_resync_fo = bit;
goto requeue;
}
@@ -719,7 +710,8 @@
size = BM_BLOCK_SIZE;
- if (drbd_try_rs_begin_io(mdev, sector)) {
+ if (drbd_rs_should_slow_down(mdev, sector) ||
+ drbd_try_rs_begin_io(mdev, sector)) {
mdev->ov_position = sector;
goto requeue;
}
