diff options
| author | Eric Dumazet <edumazet@google.com> | 2014-10-06 05:38:35 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-10-07 21:22:11 +0400 |
| commit | 0287587884b15041203b3a362d485e1ab1f24445 (patch) | |
| tree | 675ae57663c1ba3ee8768e65e7fb0e6d0259e04c /drivers/net/loopback.c | |
| 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 'drivers/net/loopback.c')
| -rw-r--r-- | drivers/net/loopback.c | 2 |
1 files changed, 1 insertions, 1 deletions
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 |