diff options
| author | Eric Dumazet <edumazet@google.com> | 2014-10-05 18:38:35 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-10-07 13:22:11 -0400 |
| commit | 0287587884b15041203b3a362d485e1ab1f24445 (patch) | |
| tree | 675ae57663c1ba3ee8768e65e7fb0e6d0259e04c /drivers/net/bonding | |
| parent | fe971b95c22578456ff7198537827841c726d3f7 (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 'drivers/net/bonding')
| -rw-r--r-- | drivers/net/bonding/bond_main.c | 9 |
1 files changed, 6 insertions, 3 deletions
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); } |