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authorJesper Dangaard Brouer <brouer@redhat.com>2020-05-14 12:49:58 +0200
committerAlexei Starovoitov <ast@kernel.org>2020-05-14 21:21:54 -0700
commit7358877ac11041a22ce1cb35c352809051eac48f (patch)
tree6458f0482c41723e6a8521fb7c1105b2d5914942
parent4a9b052a590d6217237502efde7d598156966080 (diff)
hv_netvsc: Add XDP frame size to driver
The hyperv NIC driver does memory allocation and copy even without XDP. In XDP mode it will allocate a new page for each packet and copy over the payload, before invoking the XDP BPF-prog. The positive thing it that its easy to determine the xdp.frame_sz. The XDP implementation for hv_netvsc transparently passes xdp_prog to the associated VF NIC. Many of the Azure VMs are using SRIOV, so majority of the data are actually processed directly on the VF driver's XDP path. So the overhead of the synthetic data path (hv_netvsc) is minimal. Then XDP is enabled on this driver, XDP_PASS and XDP_TX will create the SKB via build_skb (based on the newly allocated page). Now using XDP frame_sz this will provide more skb_tailroom, which netstack can use for SKB coalescing (e.g tcp_try_coalesce -> skb_try_coalesce). V3: Adjust patch desc to be more positive. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Cc: Wei Liu <wei.liu@kernel.org> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Link: https://lore.kernel.org/bpf/158945339857.97035.10212138582505736163.stgit@firesoul
-rw-r--r--drivers/net/hyperv/netvsc_bpf.c1
-rw-r--r--drivers/net/hyperv/netvsc_drv.c2
2 files changed, 2 insertions, 1 deletions
diff --git a/drivers/net/hyperv/netvsc_bpf.c b/drivers/net/hyperv/netvsc_bpf.c
index b86611041db6..1e0c024b0a93 100644
--- a/drivers/net/hyperv/netvsc_bpf.c
+++ b/drivers/net/hyperv/netvsc_bpf.c
@@ -49,6 +49,7 @@ u32 netvsc_run_xdp(struct net_device *ndev, struct netvsc_channel *nvchan,
xdp_set_data_meta_invalid(xdp);
xdp->data_end = xdp->data + len;
xdp->rxq = &nvchan->xdp_rxq;
+ xdp->frame_sz = PAGE_SIZE;
xdp->handle = 0;
memcpy(xdp->data, data, len);
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 5de57fc3ec60..6267f706e8ee 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -795,7 +795,7 @@ static struct sk_buff *netvsc_alloc_recv_skb(struct net_device *net,
if (xbuf) {
unsigned int hdroom = xdp->data - xdp->data_hard_start;
unsigned int xlen = xdp->data_end - xdp->data;
- unsigned int frag_size = netvsc_xdp_fraglen(hdroom + xlen);
+ unsigned int frag_size = xdp->frame_sz;
skb = build_skb(xbuf, frag_size);