drbd: don't let application IO pre-empt resync too often
authorLars Ellenberg <lars.ellenberg@linbit.com>
Mon, 28 Apr 2014 16:43:19 +0000 (18:43 +0200)
committerJens Axboe <axboe@fb.com>
Wed, 30 Apr 2014 19:46:54 +0000 (13:46 -0600)
commite82998743385ca861b9ec919eb2ba8177ce72180
tree4cf895d0a9633eff1f11363f98ebe60713a4bcd7
parent0e49d7b014c5d591a053d08888a455bd74a88646
drbd: don't let application IO pre-empt resync too often

Before, application IO could pre-empt resync activity
for up to hardcoded 20 seconds per resync request.
A very busy server could throttle the effective resync bandwidth
down to one request per 20 seconds.

Now, we only let application IO pre-empt resync traffic
while the current resync rate estimate is above c-min-rate.

If you disable the c-min-rate throttle feature (set c-min-rate = 0),
application IO will no longer pre-empt resync traffic at all.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
drivers/block/drbd/drbd_actlog.c
drivers/block/drbd/drbd_int.h
drivers/block/drbd/drbd_receiver.c