From 0287587884b15041203b3a362d485e1ab1f24445 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 18:38:35 -0700 Subject: [PATCH] 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 Cc: Julian Anastasov Signed-off-by: David S. Miller --- drivers/infiniband/ulp/ipoib/ipoib_main.c | 2 +- drivers/net/appletalk/ipddp.c | 2 +- drivers/net/bonding/bond_main.c | 9 ++++++--- drivers/net/eql.c | 2 +- drivers/net/ifb.c | 3 ++- drivers/net/loopback.c | 2 +- drivers/net/macvlan.c | 3 ++- drivers/net/ppp/ppp_generic.c | 2 +- drivers/net/team/team.c | 8 +++++--- drivers/net/vxlan.c | 2 +- drivers/net/wan/hdlc_fr.c | 2 +- drivers/s390/net/qeth_l3_main.c | 2 +- include/linux/netdevice.h | 8 ++++++++ net/8021q/vlan_dev.c | 3 ++- net/atm/clip.c | 2 +- net/core/dev.c | 19 +++++++++---------- net/ipv4/ip_gre.c | 2 +- net/ipv4/ip_vti.c | 2 +- net/ipv4/ipip.c | 2 +- net/ipv6/ip6_gre.c | 2 +- net/ipv6/ip6_tunnel.c | 2 +- net/ipv6/ip6_vti.c | 2 +- net/ipv6/sit.c | 2 +- net/sched/cls_flow.c | 2 ++ net/sched/cls_route.c | 1 + net/sched/sch_generic.c | 3 --- net/sched/sch_teql.c | 2 +- 27 files changed, 54 insertions(+), 39 deletions(-) diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c index 13e6e0431592..58b5aa3b6f2d 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_main.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c @@ -1364,7 +1364,7 @@ void ipoib_setup(struct net_device *dev) dev->tx_queue_len = ipoib_sendq_size * 2; dev->features = (NETIF_F_VLAN_CHALLENGED | NETIF_F_HIGHDMA); - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); memcpy(dev->broadcast, ipv4_bcast_addr, INFINIBAND_ALEN); diff --git a/drivers/net/appletalk/ipddp.c b/drivers/net/appletalk/ipddp.c index 10d0dba572c2..e90c6a7333d7 100644 --- a/drivers/net/appletalk/ipddp.c +++ b/drivers/net/appletalk/ipddp.c @@ -74,7 +74,7 @@ static struct net_device * __init ipddp_init(void) if (!dev) return ERR_PTR(-ENOMEM); - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); strcpy(dev->name, "ipddp%d"); if (version_printed++ == 0) diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 3ad5413d4f57..c9ac06cfe6b7 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -1002,7 +1002,8 @@ static netdev_features_t bond_fix_features(struct net_device *dev, static void bond_compute_features(struct bonding *bond) { - unsigned int flags, dst_release_flag = IFF_XMIT_DST_RELEASE; + unsigned int dst_release_flag = IFF_XMIT_DST_RELEASE | + IFF_XMIT_DST_RELEASE_PERM; netdev_features_t vlan_features = BOND_VLAN_FEATURES; netdev_features_t enc_features = BOND_ENC_FEATURES; struct net_device *bond_dev = bond->dev; @@ -1038,8 +1039,10 @@ done: bond_dev->gso_max_segs = gso_max_segs; netif_set_gso_max_size(bond_dev, gso_max_size); - flags = bond_dev->priv_flags & ~IFF_XMIT_DST_RELEASE; - bond_dev->priv_flags = flags | dst_release_flag; + bond_dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + if ((bond_dev->priv_flags & IFF_XMIT_DST_RELEASE_PERM) && + dst_release_flag == (IFF_XMIT_DST_RELEASE | IFF_XMIT_DST_RELEASE_PERM)) + bond_dev->priv_flags |= IFF_XMIT_DST_RELEASE; netdev_change_features(bond_dev); } diff --git a/drivers/net/eql.c b/drivers/net/eql.c index 957e5c0cede3..a10ad74cc8d2 100644 --- a/drivers/net/eql.c +++ b/drivers/net/eql.c @@ -199,7 +199,7 @@ static void __init eql_setup(struct net_device *dev) dev->type = ARPHRD_SLIP; dev->tx_queue_len = 5; /* Hands them off fast */ - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); } static int eql_open(struct net_device *dev) diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c index d2d4a3d2237f..34f846b4bd05 100644 --- a/drivers/net/ifb.c +++ b/drivers/net/ifb.c @@ -185,7 +185,8 @@ static void ifb_setup(struct net_device *dev) dev->flags |= IFF_NOARP; dev->flags &= ~IFF_MULTICAST; - dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING); + dev->priv_flags &= ~IFF_TX_SKB_SHARING; + netif_keep_dst(dev); eth_hw_addr_random(dev); } diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c index 8f2262540561..c76283c2f84a 100644 --- a/drivers/net/loopback.c +++ b/drivers/net/loopback.c @@ -169,7 +169,7 @@ static void loopback_setup(struct net_device *dev) dev->type = ARPHRD_LOOPBACK; /* 0x0001*/ dev->flags = IFF_LOOPBACK; dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); dev->hw_features = NETIF_F_ALL_TSO | NETIF_F_UFO; dev->features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_ALL_TSO diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c index e8a453f1b458..38b4fae61f04 100644 --- a/drivers/net/macvlan.c +++ b/drivers/net/macvlan.c @@ -1025,7 +1025,8 @@ void macvlan_common_setup(struct net_device *dev) { ether_setup(dev); - dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING); + dev->priv_flags &= ~IFF_TX_SKB_SHARING; + netif_keep_dst(dev); dev->priv_flags |= IFF_UNICAST_FLT; dev->netdev_ops = &macvlan_netdev_ops; dev->destructor = free_netdev; diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c index fa0d71727894..80e6f3430f65 100644 --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -1103,7 +1103,7 @@ static void ppp_setup(struct net_device *dev) dev->type = ARPHRD_PPP; dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; dev->features |= NETIF_F_NETNS_LOCAL; - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); } /* diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c index 2277c3679a51..a94a9df3e6bd 100644 --- a/drivers/net/team/team.c +++ b/drivers/net/team/team.c @@ -970,7 +970,8 @@ static void __team_compute_features(struct team *team) struct team_port *port; u32 vlan_features = TEAM_VLAN_FEATURES & NETIF_F_ALL_FOR_ALL; unsigned short max_hard_header_len = ETH_HLEN; - unsigned int flags, dst_release_flag = IFF_XMIT_DST_RELEASE; + unsigned int dst_release_flag = IFF_XMIT_DST_RELEASE | + IFF_XMIT_DST_RELEASE_PERM; list_for_each_entry(port, &team->port_list, list) { vlan_features = netdev_increment_features(vlan_features, @@ -985,8 +986,9 @@ static void __team_compute_features(struct team *team) team->dev->vlan_features = vlan_features; team->dev->hard_header_len = max_hard_header_len; - flags = team->dev->priv_flags & ~IFF_XMIT_DST_RELEASE; - team->dev->priv_flags = flags | dst_release_flag; + team->dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + if (dst_release_flag == (IFF_XMIT_DST_RELEASE | IFF_XMIT_DST_RELEASE_PERM)) + team->dev->priv_flags |= IFF_XMIT_DST_RELEASE; netdev_change_features(team->dev); } diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 2af795d6ba05..2a51e6e48e1e 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -2193,7 +2193,7 @@ static void vxlan_setup(struct net_device *dev) dev->hw_features |= NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_RXCSUM; dev->hw_features |= NETIF_F_GSO_SOFTWARE; dev->hw_features |= NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX; - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; INIT_LIST_HEAD(&vxlan->next); diff --git a/drivers/net/wan/hdlc_fr.c b/drivers/net/wan/hdlc_fr.c index e5c7e6165a4b..3ebed1c40abb 100644 --- a/drivers/net/wan/hdlc_fr.c +++ b/drivers/net/wan/hdlc_fr.c @@ -1047,7 +1047,7 @@ static void pvc_setup(struct net_device *dev) dev->flags = IFF_POINTOPOINT; dev->hard_header_len = 10; dev->addr_len = 2; - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); } static const struct net_device_ops pvc_ops = { diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c index f8427a2c4840..afebb9709763 100644 --- a/drivers/s390/net/qeth_l3_main.c +++ b/drivers/s390/net/qeth_l3_main.c @@ -3306,7 +3306,7 @@ static int qeth_l3_setup_netdev(struct qeth_card *card) card->dev->features |= NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | NETIF_F_HW_VLAN_CTAG_FILTER; - card->dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(card->dev); card->dev->gso_max_size = 15 * PAGE_SIZE; SET_NETDEV_DEV(card->dev, &card->gdev->dev); diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 2df86f50261c..3a4315b39d20 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1206,6 +1206,7 @@ enum netdev_priv_flags { IFF_SUPP_NOFCS = 1<<19, IFF_LIVE_ADDR_CHANGE = 1<<20, IFF_MACVLAN = 1<<21, + IFF_XMIT_DST_RELEASE_PERM = 1<<22, }; #define IFF_802_1Q_VLAN IFF_802_1Q_VLAN @@ -1230,6 +1231,7 @@ enum netdev_priv_flags { #define IFF_SUPP_NOFCS IFF_SUPP_NOFCS #define IFF_LIVE_ADDR_CHANGE IFF_LIVE_ADDR_CHANGE #define IFF_MACVLAN IFF_MACVLAN +#define IFF_XMIT_DST_RELEASE_PERM IFF_XMIT_DST_RELEASE_PERM /** * struct net_device - The DEVICE structure. @@ -3588,6 +3590,12 @@ static inline bool netif_supports_nofcs(struct net_device *dev) return dev->priv_flags & IFF_SUPP_NOFCS; } +/* This device needs to keep skb dst for qdisc enqueue or ndo_start_xmit() */ +static inline void netif_keep_dst(struct net_device *dev) +{ + dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | IFF_XMIT_DST_RELEASE_PERM); +} + extern struct pernet_operations __net_initdata loopback_net_ops; /* Logging, debugging and troubleshooting/diagnostic helpers. */ diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c index 35a6b6b15e8a..0d441ec8763e 100644 --- a/net/8021q/vlan_dev.c +++ b/net/8021q/vlan_dev.c @@ -799,7 +799,8 @@ void vlan_setup(struct net_device *dev) ether_setup(dev); dev->priv_flags |= IFF_802_1Q_VLAN; - dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING); + dev->priv_flags &= ~IFF_TX_SKB_SHARING; + netif_keep_dst(dev); dev->tx_queue_len = 0; dev->netdev_ops = &vlan_netdev_ops; diff --git a/net/atm/clip.c b/net/atm/clip.c index 1d9eaa4f041a..17e55dfecbe2 100644 --- a/net/atm/clip.c +++ b/net/atm/clip.c @@ -501,7 +501,7 @@ static void clip_setup(struct net_device *dev) /* without any more elaborate queuing. 100 is a reasonable */ /* compromise between decent burst-tolerance and protection */ /* against memory hogs. */ - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); } static int clip_create(int number) diff --git a/net/core/dev.c b/net/core/dev.c index a63b8c43c1b6..3c5bdaa44486 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2665,12 +2665,6 @@ static struct sk_buff *validate_xmit_skb(struct sk_buff *skb, struct net_device if (skb->next) return skb; - /* If device doesn't need skb->dst, release it right now while - * its hot in this cpu cache - */ - if (dev->priv_flags & IFF_XMIT_DST_RELEASE) - skb_dst_drop(skb); - features = netif_skb_features(skb); skb = validate_xmit_vlan(skb, features); if (unlikely(!skb)) @@ -2811,8 +2805,6 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, * waiting to be sent out; and the qdisc is not running - * xmit the skb directly. */ - if (!(dev->priv_flags & IFF_XMIT_DST_RELEASE)) - skb_dst_force(skb); qdisc_bstats_update(q, skb); @@ -2827,7 +2819,6 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, rc = NET_XMIT_SUCCESS; } else { - skb_dst_force(skb); rc = q->enqueue(skb, q) & NET_XMIT_MASK; if (qdisc_run_begin(q)) { if (unlikely(contended)) { @@ -2924,6 +2915,14 @@ static int __dev_queue_xmit(struct sk_buff *skb, void *accel_priv) skb_update_prio(skb); + /* If device/qdisc don't need skb->dst, release it right now while + * its hot in this cpu cache. + */ + if (dev->priv_flags & IFF_XMIT_DST_RELEASE) + skb_dst_drop(skb); + else + skb_dst_force(skb); + txq = netdev_pick_tx(dev, skb, accel_priv); q = rcu_dereference_bh(txq->qdisc); @@ -6674,7 +6673,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name, INIT_LIST_HEAD(&dev->adj_list.lower); INIT_LIST_HEAD(&dev->all_adj_list.upper); INIT_LIST_HEAD(&dev->all_adj_list.lower); - dev->priv_flags = IFF_XMIT_DST_RELEASE; + dev->priv_flags = IFF_XMIT_DST_RELEASE | IFF_XMIT_DST_RELEASE_PERM; setup(dev); dev->num_tx_queues = txqs; diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index 0485ef18d254..12055fdbe716 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -510,7 +510,7 @@ static int ipgre_tunnel_init(struct net_device *dev) memcpy(dev->broadcast, &iph->daddr, 4); dev->flags = IFF_NOARP; - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); dev->addr_len = 4; if (iph->daddr) { diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c index e453cb724a95..3e861011e4a3 100644 --- a/net/ipv4/ip_vti.c +++ b/net/ipv4/ip_vti.c @@ -364,7 +364,7 @@ static int vti_tunnel_init(struct net_device *dev) dev->iflink = 0; dev->addr_len = 4; dev->features |= NETIF_F_LLTX; - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); return ip_tunnel_init(dev); } diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c index ea88ab3102a8..37096d64730e 100644 --- a/net/ipv4/ipip.c +++ b/net/ipv4/ipip.c @@ -289,7 +289,7 @@ static void ipip_tunnel_setup(struct net_device *dev) dev->iflink = 0; dev->addr_len = 4; dev->features |= NETIF_F_LLTX; - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); dev->features |= IPIP_FEATURES; dev->hw_features |= IPIP_FEATURES; diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index 74b677916a70..de3b1c86b8d3 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -1242,7 +1242,7 @@ static void ip6gre_tunnel_setup(struct net_device *dev) dev->flags |= IFF_NOARP; dev->iflink = 0; dev->addr_len = sizeof(struct in6_addr); - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); } static int ip6gre_tunnel_init(struct net_device *dev) diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index d3e8888ad611..9409887fb664 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -1493,7 +1493,7 @@ static void ip6_tnl_dev_setup(struct net_device *dev) dev->mtu -= 8; dev->flags |= IFF_NOARP; dev->addr_len = sizeof(struct in6_addr); - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); /* This perm addr will be used as interface identifier by IPv6 */ dev->addr_assign_type = NET_ADDR_RANDOM; eth_random_addr(dev->perm_addr); diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c index 5833a2244467..d440bb585524 100644 --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -807,7 +807,7 @@ static void vti6_dev_setup(struct net_device *dev) dev->mtu = ETH_DATA_LEN; dev->flags |= IFF_NOARP; dev->addr_len = sizeof(struct in6_addr); - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); } /** diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index 0d4e27466f82..6eab37cf5345 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -1364,7 +1364,7 @@ static void ipip6_tunnel_setup(struct net_device *dev) dev->hard_header_len = LL_MAX_HEADER + t_hlen; dev->mtu = ETH_DATA_LEN - t_hlen; dev->flags = IFF_NOARP; - dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; + netif_keep_dst(dev); dev->iflink = 0; dev->addr_len = 4; dev->features |= NETIF_F_LLTX; 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) break; + 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->qstats.requeues++; 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); -- 2.20.1