Commit dbe4fec2 authored by Xuan Zhuo's avatar Xuan Zhuo Committed by Jakub Kicinski
Browse files

virtio_net: optimize mergeable_xdp_get_buf() 



The previous patch, in order to facilitate review, I do not do any
modification. This patch has made some optimization on the top.

* remove some repeated logics in this function.
* add fast check for passing without any alloc.

Signed-off-by: default avatarXuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent ad4858be

drivers/net/virtio_net.c

+14 −15
Original line number Diff line number Diff line
@@ -1196,6 +1196,11 @@ static void *mergeable_xdp_get_buf(struct virtnet_info *vi, 
	 */

	*frame_sz = truesize;



	if (likely(headroom >= virtnet_get_headroom(vi) &&

		   (*num_buf == 1 || xdp_prog->aux->xdp_has_frags))) {

		return page_address(*page) + offset;

	}



	/* This happens when headroom is not enough because

	 * of the buffer was prefilled before XDP is set.

	 * This should only happen for the first several packets.
@@ -1204,22 +1209,15 @@ static void *mergeable_xdp_get_buf(struct virtnet_info *vi, 
	 * support it, and we don't want to bother users who are

	 * using xdp normally.

	 */

	if (!xdp_prog->aux->xdp_has_frags &&

	    (*num_buf > 1 || headroom < virtnet_get_headroom(vi))) {

	if (!xdp_prog->aux->xdp_has_frags) {

		/* linearize data for XDP */

		xdp_page = xdp_linearize_page(rq, num_buf,

					      *page, offset,

					      VIRTIO_XDP_HEADROOM,

					      len);

		*frame_sz = PAGE_SIZE;



		if (!xdp_page)

			return NULL;

		offset = VIRTIO_XDP_HEADROOM;



		put_page(*page);

		*page = xdp_page;

	} else if (unlikely(headroom < virtnet_get_headroom(vi))) {

	} else {

		xdp_room = SKB_DATA_ALIGN(VIRTIO_XDP_HEADROOM +

					  sizeof(struct skb_shared_info));

		if (*len + xdp_room > PAGE_SIZE)
@@ -1231,14 +1229,15 @@ static void *mergeable_xdp_get_buf(struct virtnet_info *vi, 


		memcpy(page_address(xdp_page) + VIRTIO_XDP_HEADROOM,

		       page_address(*page) + offset, *len);

	}



	*frame_sz = PAGE_SIZE;

		offset = VIRTIO_XDP_HEADROOM;



	put_page(*page);



	*page = xdp_page;

	}



	return page_address(*page) + offset;

	return page_address(*page) + VIRTIO_XDP_HEADROOM;

}



static struct sk_buff *receive_mergeable(struct net_device *dev,