From 1e67575a5840908e33502b210a22509fe5d6ca53 Mon Sep 17 00:00:00 2001 From: Jesper Dangaard Brouer Date: Thu, 31 May 2018 11:00:18 +0200 Subject: [PATCH] bpf/xdp: non-map redirect can avoid calling ndo_xdp_flush This is the first real user of the XDP_XMIT_FLUSH flag. As pointed out many times, XDP_REDIRECT without using BPF maps is significant slower than the map variant. This is primary due to the lack of bulking, as the ndo_xdp_flush operation is required after each frame (to avoid frames hanging on the egress device). It is still possible to optimize this case. Instead of invoking two NDO indirect calls, which are very expensive with CONFIG_RETPOLINE, instead instruct ndo_xdp_xmit to flush via XDP_XMIT_FLUSH flag. Signed-off-by: Jesper Dangaard Brouer Acked-by: Song Liu Signed-off-by: Alexei Starovoitov --- net/core/filter.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/core/filter.c b/net/core/filter.c index 56e40dafdde7..a72ea9f61010 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3056,10 +3056,9 @@ static int __bpf_tx_xdp(struct net_device *dev, if (unlikely(!xdpf)) return -EOVERFLOW; - sent = dev->netdev_ops->ndo_xdp_xmit(dev, 1, &xdpf, 0); + sent = dev->netdev_ops->ndo_xdp_xmit(dev, 1, &xdpf, XDP_XMIT_FLUSH); if (sent <= 0) return sent; - dev->netdev_ops->ndo_xdp_flush(dev); return 0; } -- 2.30.2