From fe60faa5063822f2d555f4f326c7dd72a60929bf Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 31 Oct 2018 08:39:13 -0700 Subject: net: do not abort bulk send on BQL status Before calling dev_hard_start_xmit(), upper layers tried to cook optimal skb list based on BQL budget. Problem is that GSO packets can end up comsuming more than the BQL budget. Breaking the loop is not useful, since requeued packets are ahead of any packets still in the qdisc. It is also more expensive, since next TX completion will push these packets later, while skbs are not in cpu caches. It is also a behavior difference with TSO packets, that can break the BQL limit by a large amount. Note that drivers should use __netdev_tx_sent_queue() in order to have optimal xmit_more support, and avoid useless atomic operations as shown in the following patch. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index 77d43ae2a7bb..0ffcbdd55fa9 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3272,7 +3272,7 @@ struct sk_buff *dev_hard_start_xmit(struct sk_buff *first, struct net_device *de } skb = next; - if (netif_xmit_stopped(txq) && skb) { + if (netif_tx_queue_stopped(txq) && skb) { rc = NETDEV_TX_BUSY; break; } -- cgit From 33d9a2c72f086cbf1087b2fd2d1a15aa9df14a7f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sat, 17 Nov 2018 21:57:02 -0800 Subject: net-gro: reset skb->pkt_type in napi_reuse_skb() eth_type_trans() assumes initial value for skb->pkt_type is PACKET_HOST. This is indeed the value right after a fresh skb allocation. However, it is possible that GRO merged a packet with a different value (like PACKET_OTHERHOST in case macvlan is used), so we need to make sure napi->skb will have pkt_type set back to PACKET_HOST. Otherwise, valid packets might be dropped by the stack because their pkt_type is not PACKET_HOST. napi_reuse_skb() was added in commit 96e93eab2033 ("gro: Add internal interfaces for VLAN"), but this bug always has been there. Fixes: 96e93eab2033 ("gro: Add internal interfaces for VLAN") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/dev.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index 0ffcbdd55fa9..066aa902d85c 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5655,6 +5655,10 @@ static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb) skb->vlan_tci = 0; skb->dev = napi->dev; skb->skb_iif = 0; + + /* eth_type_trans() assumes pkt_type is PACKET_HOST */ + skb->pkt_type = PACKET_HOST; + skb->encapsulation = 0; skb_shinfo(skb)->gso_type = 0; skb->truesize = SKB_TRUESIZE(skb_end_offset(skb)); -- cgit From 605108acfe6233b72e2f803aa1cb59a2af3001ca Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Wed, 21 Nov 2018 18:21:35 +0100 Subject: net: don't keep lonely packets forever in the gro hash Eric noted that with UDP GRO and NAPI timeout, we could keep a single UDP packet inside the GRO hash forever, if the related NAPI instance calls napi_gro_complete() at an higher frequency than the NAPI timeout. Willem noted that even TCP packets could be trapped there, till the next retransmission. This patch tries to address the issue, flushing the old packets - those with a NAPI_GRO_CB age before the current jiffy - before scheduling the NAPI timeout. The rationale is that such a timeout should be well below a jiffy and we are not flushing packets eligible for sane GRO. v1 -> v2: - clarified the commit message and comment RFC -> v1: - added 'Fixes tags', cleaned-up the wording. Reported-by: Eric Dumazet Fixes: 3b47d30396ba ("net: gro: add a per device gro flush timer") Signed-off-by: Paolo Abeni Acked-by: Willem de Bruijn Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/dev.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index 066aa902d85c..ddc551f24ba2 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5970,11 +5970,14 @@ bool napi_complete_done(struct napi_struct *n, int work_done) if (work_done) timeout = n->dev->gro_flush_timeout; + /* When the NAPI instance uses a timeout and keeps postponing + * it, we need to bound somehow the time packets are kept in + * the GRO layer + */ + napi_gro_flush(n, !!timeout); if (timeout) hrtimer_start(&n->timer, ns_to_ktime(timeout), HRTIMER_MODE_REL_PINNED); - else - napi_gro_flush(n, false); } if (unlikely(!list_empty(&n->poll_list))) { /* If n->poll_list is not empty, we need to mask irqs */ -- cgit