From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755950AbaHYNZD (ORCPT ); Mon, 25 Aug 2014 09:25:03 -0400 Received: from zimbra13.linbit.com ([212.69.166.240]:56664 "EHLO zimbra13.linbit.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755724AbaHYNZA (ORCPT ); Mon, 25 Aug 2014 09:25:00 -0400 X-Greylist: delayed 499 seconds by postgrey-1.27 at vger.kernel.org; Mon, 25 Aug 2014 09:25:00 EDT From: Philipp Reisner To: linux-kernel@vger.kernel.org, Jens Axboe Cc: drbd-dev@lists.linbit.com Subject: [PATCH 8/8] drbd: reduce lock contention in drbd_worker Date: Mon, 25 Aug 2014 15:16:38 +0200 Message-Id: <1408972598-16650-9-git-send-email-philipp.reisner@linbit.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1408972598-16650-1-git-send-email-philipp.reisner@linbit.com> References: <1408972598-16650-1-git-send-email-philipp.reisner@linbit.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lars Ellenberg 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 --- drivers/block/drbd/drbd_worker.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c index 3ed2d87..d2d1f97 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(); -- 1.9.1