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authorLars Ellenberg <lars.ellenberg@linbit.com>2013-03-19 18:16:58 +0100
committerJens Axboe <axboe@kernel.dk>2013-03-22 22:18:09 -0600
commit45ad07b3ac1e3062188fb760fe71cafb4a100215 (patch)
tree3911830e2d53a830007f6d70fdac39d00d065bb2 /drivers/block/drbd/drbd_req.c
parent7e8c288f6cde950a6ca001ec06a32c8c2cf4180e (diff)
downloadvexpress-lsk-45ad07b3ac1e3062188fb760fe71cafb4a100215.tar.gz
drbd: try hard to max out the updates per AL transaction
There may have been more incoming requests while we where preparing the current transaction. Try to consolidate more updates into this transaction until we make no more progres. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block/drbd/drbd_req.c')
-rw-r--r--drivers/block/drbd/drbd_req.c31
1 files changed, 31 insertions, 0 deletions
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index d72f2fef1cb..9f7ff1cb46f 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -1226,6 +1226,37 @@ void do_submit(struct work_struct *ws)
break;
wait_event(mdev->al_wait, prepare_al_transaction_nonblock(mdev, &incoming, &pending));
+ /* Maybe more was queued, while we prepared the transaction?
+ * Try to stuff them into this transaction as well.
+ * Be strictly non-blocking here, no wait_event, we already
+ * have something to commit.
+ * Stop if we don't make any more progres.
+ */
+ for (;;) {
+ LIST_HEAD(more_pending);
+ LIST_HEAD(more_incoming);
+ bool made_progress;
+
+ /* It is ok to look outside the lock,
+ * it's only an optimization anyways */
+ if (list_empty(&mdev->submit.writes))
+ break;
+
+ spin_lock(&mdev->submit.lock);
+ list_splice_tail_init(&mdev->submit.writes, &more_incoming);
+ spin_unlock(&mdev->submit.lock);
+
+ if (list_empty(&more_incoming))
+ break;
+
+ made_progress = prepare_al_transaction_nonblock(mdev, &more_incoming, &more_pending);
+
+ list_splice_tail_init(&more_pending, &pending);
+ list_splice_tail_init(&more_incoming, &incoming);
+
+ if (!made_progress)
+ break;
+ }
drbd_al_begin_io_commit(mdev, false);
list_for_each_entry_safe(req, tmp, &pending, tl_requests) {