path: root/net/sched
diff options
authorEric Dumazet <edumazet@google.com>2014-10-05 18:38:35 -0700
committerDavid S. Miller <davem@davemloft.net>2014-10-07 13:22:11 -0400
commit0287587884b15041203b3a362d485e1ab1f24445 (patch)
tree675ae57663c1ba3ee8768e65e7fb0e6d0259e04c /net/sched
parentnet/mlx4_en: remove NETDEV_TX_BUSY (diff)
net: better IFF_XMIT_DST_RELEASE support
Testing xmit_more support with netperf and connected UDP sockets, I found strange dst refcount false sharing. Current handling of IFF_XMIT_DST_RELEASE is not optimal. Dropping dst in validate_xmit_skb() is certainly too late in case packet was queued by cpu X but dequeued by cpu Y The logical point to take care of drop/force is in __dev_queue_xmit() before even taking qdisc lock. As Julian Anastasov pointed out, need for skb_dst() might come from some packet schedulers or classifiers. This patch adds new helper to cleanly express needs of various drivers or qdiscs/classifiers. Drivers that need skb_dst() in their ndo_start_xmit() should call following helper in their setup instead of the prior : dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; -> netif_keep_dst(dev); Instead of using a single bit, we use two bits, one being eventually rebuilt in bonding/team drivers. The other one, is permanent and blocks IFF_XMIT_DST_RELEASE being rebuilt in bonding/team. Eventually, we could add something smarter later. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
4 files changed, 4 insertions, 4 deletions
diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c
index a5d2b20db560..4ac515f2a6ce 100644
--- a/net/sched/cls_flow.c
+++ b/net/sched/cls_flow.c
@@ -493,6 +493,8 @@ static int flow_change(struct net *net, struct sk_buff *in_skb,
tcf_exts_change(tp, &fnew->exts, &e);
tcf_em_tree_change(tp, &fnew->ematches, &t);
+ netif_keep_dst(qdisc_dev(tp->q));
if (tb[TCA_FLOW_KEYS]) {
fnew->keymask = keymask;
fnew->nkeys = nkeys;
diff --git a/net/sched/cls_route.c b/net/sched/cls_route.c
index 6f22baae0afa..109a329b7198 100644
--- a/net/sched/cls_route.c
+++ b/net/sched/cls_route.c
@@ -524,6 +524,7 @@ static int route4_change(struct net *net, struct sk_buff *in_skb,
if (f->handle < f1->handle)
+ netif_keep_dst(qdisc_dev(tp->q));
rcu_assign_pointer(f->next, f1);
rcu_assign_pointer(*fp, f);
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 2b349a4de3c8..38d58e6cef07 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -47,7 +47,6 @@ EXPORT_SYMBOL(default_qdisc_ops);
static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
- skb_dst_force(skb);
q->gso_skb = skb;
q->q.qlen++; /* it's still part of the queue */
@@ -218,8 +217,6 @@ static inline int qdisc_restart(struct Qdisc *q)
if (unlikely(!skb))
return 0;
- WARN_ON_ONCE(skb_dst_is_noref(skb));
root_lock = qdisc_lock(q);
dev = qdisc_dev(q);
txq = skb_get_tx_queue(dev, skb);
diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
index 5cd291bd00e4..6ada42396a24 100644
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -470,7 +470,7 @@ static __init void teql_master_setup(struct net_device *dev)
dev->tx_queue_len = 100;
dev->flags = IFF_NOARP;
dev->hard_header_len = LL_MAX_HEADER;
- dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
+ netif_keep_dst(dev);
static LIST_HEAD(master_dev_list);