diff options
| author | Eric Dumazet <edumazet@google.com> | 2014-10-06 01:38:35 (GMT) |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-10-07 17:22:11 (GMT) |
| commit | 0287587884b15041203b3a362d485e1ab1f24445 (patch) | |
| tree | 675ae57663c1ba3ee8768e65e7fb0e6d0259e04c /net/ipv4 | |
| parent | fe971b95c22578456ff7198537827841c726d3f7 (diff) | |
| download | linux-0287587884b15041203b3a362d485e1ab1f24445.tar.xz | |
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/ipv4')
| -rw-r--r-- | net/ipv4/ip_gre.c | 2 | ||||
| -rw-r--r-- | net/ipv4/ip_vti.c | 2 | ||||
| -rw-r--r-- | net/ipv4/ipip.c | 2 |
3 files changed, 3 insertions, 3 deletions
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index 0485ef1..12055fd 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 e453cb7..3e86101 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 ea88ab3..37096d6 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; |