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drbd: reduce lock contention in drbd_worker 

The worker may now dequeue work items in batches.
This should reduce lock contention during busy periods.

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>
hifive-unleashed-5.1
Lars Ellenberg 2014-09-11 14:29:12 +02:00 committed by Jens Axboe
parent abde9cc6a5
commit 729e8b87ba
1 changed files with 4 additions and 6 deletions
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10
drivers/block/drbd/drbd_worker.c
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@ -2026,8 +2026,6 @@ static void wait_for_work(struct drbd_connection *connection, struct list_head *
prepare_to_wait(&connection->sender_work.q_wait, &wait, TASK_INTERRUPTIBLE);
spin_lock_irq(&connection->resource->req_lock);
spin_lock(&connection->sender_work.q_lock); /* FIXME get rid of this one? */
/* dequeue single item only,
* we still use drbd_queue_work_front() in some places */
if (!list_empty(&connection->sender_work.q))
list_splice_tail_init(&connection->sender_work.q, work_list);
spin_unlock(&connection->sender_work.q_lock); /* FIXME get rid of this one? */
@ -2114,7 +2112,7 @@ int drbd_worker(struct drbd_thread *thi)
if (get_t_state(thi) != RUNNING)
break;
while (!list_empty(&work_list)) {
if (!list_empty(&work_list)) {
w = list_first_entry(&work_list, struct drbd_work, list);
list_del_init(&w->list);
update_worker_timing_details(connection, w->cb);
@ -2130,13 +2128,13 @@ int drbd_worker(struct drbd_thread *thi)
update_worker_timing_details(connection, do_unqueued_work);
do_unqueued_work(connection);
}
while (!list_empty(&work_list)) {
if (!list_empty(&work_list)) {
w = list_first_entry(&work_list, struct drbd_work, list);
list_del_init(&w->list);
update_worker_timing_details(connection, w->cb);
w->cb(w, 1);
}
dequeue_work_batch(&connection->sender_work, &work_list);
} else
dequeue_work_batch(&connection->sender_work, &work_list);
} while (!list_empty(&work_list) || test_bit(DEVICE_WORK_PENDING, &connection->flags));
rcu_read_lock();