From: Paolo Bonzini <pbonzini@redhat.com> To: linux-kernel@vger.kernel.org Cc: Wanlong Gao <gaowanlong@cn.fujitsu.com>, asias@redhat.com, Rusty Russell <rusty@rustcorp.com.au>, mst@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: [RFC PATCH 6/8] virtio-net: unmark scatterlist ending after virtqueue_add_buf Date: Thu, 7 Feb 2013 13:22:30 +0100 [thread overview] Message-ID: <1360239752-2470-7-git-send-email-pbonzini@redhat.com> (raw) In-Reply-To: <1360239752-2470-1-git-send-email-pbonzini@redhat.com> Prepare for when virtqueue_add_buf will use sg_next instead of ignoring ending markers. Note that for_each_sg (and thus virtqueue_add_buf) allows you to pass a "truncated" scatterlist that does not have a marker on the last item. We rely on this in add_recvbuf_mergeable. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- This is the only part that survived of Rusty's ideas. :) drivers/net/virtio_net.c | 21 ++++++++++++++++----- 1 files changed, 16 insertions(+), 5 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 35c00c5..ce08b54 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -440,13 +440,17 @@ static int add_recvbuf_small(struct receive_queue *rq, gfp_t gfp) hdr = skb_vnet_hdr(skb); sg_set_buf(rq->sg, &hdr->hdr, sizeof hdr->hdr); - skb_to_sgvec(skb, rq->sg + 1, 0, skb->len); err = virtqueue_add_buf(rq->vq, rq->sg, 0, 2, skb, gfp); if (err < 0) dev_kfree_skb(skb); + /* + * An optimization: clear the end bit set by skb_to_sgvec, so + * we can simply re-use rq->sg[] next time. + */ + sg_unmark_end(rq->sg + 1); return err; } @@ -505,8 +509,7 @@ static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp) if (!page) return -ENOMEM; - sg_init_one(rq->sg, page_address(page), PAGE_SIZE); - + sg_set_page(rq->sg, page, PAGE_SIZE, 0); err = virtqueue_add_buf(rq->vq, rq->sg, 0, 1, page, gfp); if (err < 0) give_pages(rq, page); @@ -671,6 +674,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest; struct virtnet_info *vi = sq->vq->vdev->priv; unsigned num_sg; + int ret; pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest); @@ -710,8 +714,15 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) sg_set_buf(sq->sg, &hdr->hdr, sizeof hdr->hdr); num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1; - return virtqueue_add_buf(sq->vq, sq->sg, num_sg, - 0, skb, GFP_ATOMIC); + ret = virtqueue_add_buf(sq->vq, sq->sg, num_sg, + 0, skb, GFP_ATOMIC); + + /* + * An optimization: clear the end bit set by skb_to_sgvec, so + * we can simply re-use sq->sg[] next time. + */ + sg_unmark_end(&sq->sg[num_sg-1]); + return ret; } static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) -- 1.7.1
WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com> To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, mst@redhat.com, virtualization@lists.linux-foundation.org Subject: [RFC PATCH 6/8] virtio-net: unmark scatterlist ending after virtqueue_add_buf Date: Thu, 7 Feb 2013 13:22:30 +0100 [thread overview] Message-ID: <1360239752-2470-7-git-send-email-pbonzini@redhat.com> (raw) In-Reply-To: <1360239752-2470-1-git-send-email-pbonzini@redhat.com> Prepare for when virtqueue_add_buf will use sg_next instead of ignoring ending markers. Note that for_each_sg (and thus virtqueue_add_buf) allows you to pass a "truncated" scatterlist that does not have a marker on the last item. We rely on this in add_recvbuf_mergeable. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- This is the only part that survived of Rusty's ideas. :) drivers/net/virtio_net.c | 21 ++++++++++++++++----- 1 files changed, 16 insertions(+), 5 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 35c00c5..ce08b54 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -440,13 +440,17 @@ static int add_recvbuf_small(struct receive_queue *rq, gfp_t gfp) hdr = skb_vnet_hdr(skb); sg_set_buf(rq->sg, &hdr->hdr, sizeof hdr->hdr); - skb_to_sgvec(skb, rq->sg + 1, 0, skb->len); err = virtqueue_add_buf(rq->vq, rq->sg, 0, 2, skb, gfp); if (err < 0) dev_kfree_skb(skb); + /* + * An optimization: clear the end bit set by skb_to_sgvec, so + * we can simply re-use rq->sg[] next time. + */ + sg_unmark_end(rq->sg + 1); return err; } @@ -505,8 +509,7 @@ static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp) if (!page) return -ENOMEM; - sg_init_one(rq->sg, page_address(page), PAGE_SIZE); - + sg_set_page(rq->sg, page, PAGE_SIZE, 0); err = virtqueue_add_buf(rq->vq, rq->sg, 0, 1, page, gfp); if (err < 0) give_pages(rq, page); @@ -671,6 +674,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest; struct virtnet_info *vi = sq->vq->vdev->priv; unsigned num_sg; + int ret; pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest); @@ -710,8 +714,15 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) sg_set_buf(sq->sg, &hdr->hdr, sizeof hdr->hdr); num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1; - return virtqueue_add_buf(sq->vq, sq->sg, num_sg, - 0, skb, GFP_ATOMIC); + ret = virtqueue_add_buf(sq->vq, sq->sg, num_sg, + 0, skb, GFP_ATOMIC); + + /* + * An optimization: clear the end bit set by skb_to_sgvec, so + * we can simply re-use sq->sg[] next time. + */ + sg_unmark_end(&sq->sg[num_sg-1]); + return ret; } static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) -- 1.7.1
next prev parent reply other threads:[~2013-02-07 12:24 UTC|newest] Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-02-07 12:22 [RFC PATCH 0/8] virtio: new API for addition of buffers, scatterlist changes Paolo Bonzini 2013-02-07 12:22 ` Paolo Bonzini 2013-02-07 12:22 ` [RFC PATCH 1/8] virtio: add functions for piecewise addition of buffers Paolo Bonzini 2013-02-07 12:22 ` Paolo Bonzini 2013-02-07 12:22 ` [RFC PATCH 2/8] virtio-blk: reorganize virtblk_add_req Paolo Bonzini 2013-02-07 12:22 ` Paolo Bonzini 2013-02-07 12:22 ` [RFC PATCH 3/8] virtio-blk: use virtqueue_start_buf on bio path Paolo Bonzini 2013-02-07 12:22 ` Paolo Bonzini 2013-02-07 12:22 ` [RFC PATCH 4/8] virtio-blk: use virtqueue_start_buf on req path Paolo Bonzini 2013-02-07 12:22 ` Paolo Bonzini 2013-02-07 12:22 ` [RFC PATCH 5/8] scatterlist: introduce sg_unmark_end Paolo Bonzini 2013-02-07 12:22 ` Paolo Bonzini 2013-02-07 12:35 ` Jens Axboe 2013-02-07 12:35 ` Jens Axboe 2013-02-07 12:22 ` Paolo Bonzini [this message] 2013-02-07 12:22 ` [RFC PATCH 6/8] virtio-net: unmark scatterlist ending after virtqueue_add_buf Paolo Bonzini 2013-02-07 12:22 ` [RFC PATCH 7/8] virtio-scsi: use virtqueue_start_buf Paolo Bonzini 2013-02-07 12:22 ` Paolo Bonzini 2013-02-07 12:22 ` [RFC PATCH 8/8] virtio: reimplement virtqueue_add_buf using new functions Paolo Bonzini 2013-02-07 12:22 ` Paolo Bonzini 2013-02-07 13:09 ` [RFC PATCH 0/8] virtio: new API for addition of buffers, scatterlist changes Michael S. Tsirkin 2013-02-07 13:09 ` Michael S. Tsirkin 2013-02-07 13:14 ` Paolo Bonzini 2013-02-07 13:14 ` Paolo Bonzini 2013-02-07 13:23 ` Michael S. Tsirkin 2013-02-07 13:23 ` Michael S. Tsirkin 2013-02-07 13:20 ` Paolo Bonzini 2013-02-07 13:20 ` Paolo Bonzini 2013-02-07 13:31 ` Michael S. Tsirkin 2013-02-07 13:31 ` Michael S. Tsirkin 2013-02-07 13:30 ` Paolo Bonzini 2013-02-07 13:30 ` Paolo Bonzini 2013-02-08 4:05 ` Rusty Russell 2013-02-08 4:05 ` Rusty Russell 2013-02-08 6:35 ` Paolo Bonzini 2013-02-08 6:35 ` Paolo Bonzini 2013-02-08 11:52 ` Jens Axboe 2013-02-08 11:52 ` Jens Axboe 2013-02-13 9:46 ` Rusty Russell 2013-02-13 9:46 ` Rusty Russell
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