From: Lars Ellenberg Date: Thu, 11 Sep 2014 12:29:12 +0000 (+0200) Subject: drbd: reduce lock contention in drbd_worker X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=729e8b87bac63dee09302ddffc05a7ba0e50c9ad;p=openwrt%2Fstaging%2Fblogic.git 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 Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe --- diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c index 3ed2d871272e..d2d1f97511bd 100644 --- a/drivers/block/drbd/drbd_worker.c +++ b/drivers/block/drbd/drbd_worker.c @@ -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();