Messages in this thread Patch in this message | | | From | Philipp Reisner <> | Subject | [PATCH 02/18] drbd: only wakeup if something changed in update_peer_seq | Date | Thu, 1 Sep 2011 14:48:49 +0200 |
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From: Lars Ellenberg <lars.ellenberg@linbit.com>
This commit got it wrong: drbd: Make the peer_seq updating code more obvious
Make it more clear that update_peer_seq() is supposed to wake up the seq_wait queue whenever the sequence number changes.
We don't need to wake up everytime we receive a sequence number that is _different_ from our currently stored "newest" sequence number, but only if we receive a sequence number _newer_ than what we already have, when we actually change mdev->peer_seq.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> --- drivers/block/drbd/drbd_receiver.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index 620f27f..64f658b 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -1737,14 +1737,15 @@ static bool need_peer_seq(struct drbd_conf *mdev) static void update_peer_seq(struct drbd_conf *mdev, unsigned int peer_seq) { - unsigned int old_peer_seq; + unsigned int newest_peer_seq; if (need_peer_seq(mdev)) { spin_lock(&mdev->peer_seq_lock); - old_peer_seq = mdev->peer_seq; - mdev->peer_seq = seq_max(mdev->peer_seq, peer_seq); + newest_peer_seq = seq_max(mdev->peer_seq, peer_seq); + mdev->peer_seq = newest_peer_seq; spin_unlock(&mdev->peer_seq_lock); - if (old_peer_seq != peer_seq) + /* wake up only if we actually changed mdev->peer_seq */ + if (peer_seq == newest_peer_seq) wake_up(&mdev->seq_wait); } } -- 1.7.4.1
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