From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-4993-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id AF995985CB0 for ; Wed, 21 Nov 2018 10:05:41 +0000 (UTC) From: Tiwei Bie Date: Wed, 21 Nov 2018 18:03:23 +0800 Message-Id: <20181121100330.24846-7-tiwei.bie@intel.com> In-Reply-To: <20181121100330.24846-1-tiwei.bie@intel.com> References: <20181121100330.24846-1-tiwei.bie@intel.com> Subject: [virtio-dev] [PATCH net-next v3 06/13] virtio_ring: introduce helper for indirect feature To: mst@redhat.com, jasowang@redhat.com, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, virtio-dev@lists.oasis-open.org Cc: wexu@redhat.com, jfreimann@redhat.com, maxime.coquelin@redhat.com, tiwei.bie@intel.com List-ID: Introduce a helper to check whether we will use indirect feature. It will be used by packed ring too. Signed-off-by: Tiwei Bie --- drivers/virtio/virtio_ring.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 10d407910aa2..d1076f28c7e9 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -145,6 +145,18 @@ struct vring_virtqueue { #define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq) +static inline bool virtqueue_use_indirect(struct virtqueue *_vq, + unsigned int total_sg) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + + /* + * If the host supports indirect descriptor tables, and we have multiple + * buffers, then go indirect. FIXME: tune this threshold + */ + return (vq->indirect && total_sg > 1 && vq->vq.num_free); +} + /* * Modern virtio devices have feature bits to specify whether they need a * quirk and bypass the IOMMU. If not there, just use the DMA API. @@ -324,9 +336,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, head = vq->free_head; - /* If the host supports indirect descriptor tables, and we have multiple - * buffers, then go indirect. FIXME: tune this threshold */ - if (vq->indirect && total_sg > 1 && vq->vq.num_free) + if (virtqueue_use_indirect(_vq, total_sg)) desc = alloc_indirect_split(_vq, total_sg, gfp); else { desc = NULL; -- 2.14.5 --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org