Jason Wang
2022-Mar-29 04:57 UTC
[PATCH 2/2] virtio_ring: add unlikely annotation for free descs check
On Mon, Mar 28, 2022 at 6:58 PM Xianting Tian <xianting.tian at linux.alibaba.com> wrote:> > The 'if (vq->vq.num_free < descs_used)' check will almost always be false. > > Signed-off-by: Xianting Tian <xianting.tian at linux.alibaba.com>Acked-by: Jason Wang <jasowang at redhat.com>> --- > drivers/virtio/virtio_ring.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index d597fc0874ec..ab6d5f0cb579 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -525,7 +525,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > descs_used = total_sg; > } > > - if (vq->vq.num_free < descs_used) { > + if (unlikely(vq->vq.num_free < descs_used)) { > pr_debug("Can't add buf len %i - avail = %i\n", > descs_used, vq->vq.num_free); > /* FIXME: for historical reasons, we force a notify here if > -- > 2.17.1 >