drbd: queue writes on submitter thread, unless they pass the activity log fastpath (779b3fe4) · Commits · 戴 / test

drivers/block/drbd/drbd_req.c

+12 −8

Original line number	Diff line number	Diff line
		@@ -1020,6 +1020,14 @@ drbd_submit_req_private_bio(struct drbd_request *req)
		bio_endio(bio, -EIO);
		}

		static void drbd_queue_write(struct drbd_conf mdev, struct drbd_request req)
		{
		spin_lock(&mdev->submit.lock);
		list_add_tail(&req->tl_requests, &mdev->submit.writes);
		spin_unlock(&mdev->submit.lock);
		queue_work(mdev->submit.wq, &mdev->submit.worker);
		}

		/* returns the new drbd_request pointer, if the caller is expected to
		* drbd_send_and_submit() it (to save latency), or NULL if we queued the
		* request on the submitter thread.
		@@ -1048,17 +1056,13 @@ drbd_request_prepare(struct drbd_conf mdev, struct bio bio, unsigned long star
		req->private_bio = NULL;
		}

		/* For WRITES going to the local disk, grab a reference on the target
		* extent. This waits for any resync activity in the corresponding
		* resync extent to finish, and, if necessary, pulls in the target
		* extent into the activity log, which involves further disk io because
		* of transactional on-disk meta data updates.
		* Empty flushes don't need to go into the activity log, they can only
		* flush data for pending writes which are already in there. */
		if (rw == WRITE && req->private_bio && req->i.size
		&& !test_bit(AL_SUSPENDED, &mdev->flags)) {
		if (!drbd_al_begin_io_fastpath(mdev, &req->i)) {
		drbd_queue_write(mdev, req);
		return NULL;
		}
		req->rq_state \|= RQ_IN_ACT_LOG;
		drbd_al_begin_io(mdev, &req->i, true);
		}

		return req;