On Mon, Nov 26, 2018 at 09:35:53AM -0700, Jens Axboe wrote:
> We need this for blk-mq to kick things into gear, if we told it that
> we had more IO coming, but then failed to deliver on that promise.
>
> Signed-off-by: Jens Axboe <ax...@kernel.dk>
> ---
> drivers/block/virtio_blk.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index 6e869d05f91e..b49c57e77780 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -214,6 +214,20 @@ static void virtblk_done(struct virtqueue *vq)
> spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
> }
>
> +static void virtio_commit_rqs(struct blk_mq_hw_ctx *hctx)
> +{
> + struct virtio_blk *vblk = hctx->queue->queuedata;
> + int qid = hctx->queue_num;
> + bool kick;
> +
> + spin_lock_irq(&vblk->vqs[qid].lock);
> + kick = virtqueue_kick_prepare(vblk->vqs[qid].vq);
> + spin_unlock_irq(&vblk->vqs[qid].lock);
> +
> + if (kick)
> + virtqueue_notify(vblk->vqs[qid].vq);
> +}
> +
> static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
> const struct blk_mq_queue_data *bd)
> {
> @@ -638,6 +652,7 @@ static void virtblk_initialize_rq(struct request *req)
>
> static const struct blk_mq_ops virtio_mq_ops = {
> .queue_rq = virtio_queue_rq,
> + .commit_rqs = virtio_commit_rqs,
> .complete = virtblk_request_done,
> .init_request = virtblk_init_request,
> #ifdef CONFIG_VIRTIO_BLK_SCSI
> --
> 2.17.1
>
If .commit_rqs() is implemented, virtqueue_notify() in virtio_queue_rq()
should have been removed for saving the world switch per .queue_rq()
thanks,
Ming
