+
+ /*
+ * A list of buffers which can be used for aggregate I/O, this
+ * avoids the need to allocate them on demand when memory is low.
+ */
+ list_create(&vq->vq_io_list, sizeof (vdev_io_t),
+ offsetof(vdev_io_t, vi_node));
+
+ for (i = 0; i < zfs_vdev_max_pending; i++)
+ list_insert_tail(&vq->vq_io_list, zio_vdev_alloc());