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_actlog.c b/drivers/block/drbd/drbd_actlog.c
index 33f6cc5..28f85d9 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -182,6 +182,7 @@
if (unlikely(tmp != NULL)) {
struct bm_extent *bm_ext = lc_entry(tmp, struct bm_extent, lce);
if (test_bit(BME_NO_WRITES, &bm_ext->flags)) {
+ set_bit(BME_PRIORITY, &bm_ext->flags);
spin_unlock_irq(&mdev->al_lock);
return NULL;
}
@@ -1297,8 +1298,7 @@
}
if (lc_put(mdev->resync, &bm_ext->lce) == 0) {
- clear_bit(BME_LOCKED, &bm_ext->flags);
- clear_bit(BME_NO_WRITES, &bm_ext->flags);
+ bm_ext->flags = 0; /* clear BME_LOCKED, BME_NO_WRITES and BME_PRIORITY */
mdev->resync_locked--;
wake_up(&mdev->al_wait);
}