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authorLars Ellenberg2012-06-14 15:14:06 +0200
committerPhilipp Reisner2012-07-24 14:07:18 +0200
commitc2ba686f353972cc89a006ffb6bab7ba1822271e (patch)
tree666920e336f5e85cdf4d03ecafa165c6a65743a4 /drivers/block/drbd/drbd_main.c
parentdrbd: differentiate between normal and forced detach (diff)
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drbd: report congestion if we are waiting for some userland callback
If the drbd worker thread is synchronously waiting for some userland callback, we don't want some casual pageout to block on us. Have drbd_congested() report congestion in that case. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Diffstat (limited to 'drivers/block/drbd/drbd_main.c')
-rw-r--r--drivers/block/drbd/drbd_main.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 5bebe8d8ace3..41ccb580d5ac 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -3553,6 +3553,22 @@ static int drbd_congested(void *congested_data, int bdi_bits)
goto out;
}
+ if (test_bit(CALLBACK_PENDING, &mdev->flags)) {
+ r |= (1 << BDI_async_congested);
+ /* Without good local data, we would need to read from remote,
+ * and that would need the worker thread as well, which is
+ * currently blocked waiting for that usermode helper to
+ * finish.
+ */
+ if (!get_ldev_if_state(mdev, D_UP_TO_DATE))
+ r |= (1 << BDI_sync_congested);
+ else
+ put_ldev(mdev);
+ r &= bdi_bits;
+ reason = 'c';
+ goto out;
+ }
+
if (get_ldev(mdev)) {
q = bdev_get_queue(mdev->ldev->backing_bdev);
r = bdi_congested(&q->backing_dev_info, bdi_bits);