linux-stable/drivers/net/team
Eric Dumazet 0287587884 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>
2014-10-07 13:22:11 -04:00
..
Kconfig team: introduce random mode 2013-03-06 14:55:20 -05:00
Makefile team: introduce random mode 2013-03-06 14:55:20 -05:00
team.c net: better IFF_XMIT_DST_RELEASE support 2014-10-07 13:22:11 -04:00
team_mode_activebackup.c
team_mode_broadcast.c team: introduce two default team_modeop functions and use them in modes 2013-03-06 14:55:20 -05:00
team_mode_loadbalance.c net: filter: split 'struct sk_filter' into socket and bpf parts 2014-08-02 15:03:58 -07:00
team_mode_random.c random32: add prandom_u32_max and convert open coded users 2014-01-21 23:17:20 -08:00
team_mode_roundrobin.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-06-19 16:49:39 -07:00