Stefano Garzarella
2022-Mar-29 07:50 UTC
[PATCH 2/2] virtio_ring: add unlikely annotation for free descs check
On Mon, Mar 28, 2022 at 06:58:17PM +0800, Xianting Tian 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> >--- > drivers/virtio/virtio_ring.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-)Reviewed-by: Stefano Garzarella <sgarzare at redhat.com>> >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 >