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authorHerbert Xu <herbert@gondor.apana.org.au>2010-07-21 21:44:31 +0000
committerDavid S. Miller <davem@davemloft.net>2010-07-22 13:08:56 -0700
commit8a35747a5d13b99e076b0222729e0caa48cb69b6 (patch)
tree387e2840fe46edd9cc36027cf188778f2c5ab1ff /drivers
parentbded64a7ff82f6af56426a4ff2483888e5ad5fe9 (diff)
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macvtap: Limit packet queue length
Mark Wagner reported OOM symptoms when sending UDP traffic over a macvtap link to a kvm receiver. This appears to be caused by the fact that macvtap packet queues are unlimited in length. This means that if the receiver can't keep up with the rate of flow, then we will hit OOM. Of course it gets worse if the OOM killer then decides to kill the receiver. This patch imposes a cap on the packet queue length, in the same way as the tuntap driver, using the device TX queue length. Please note that macvtap currently has no way of giving congestion notification, that means the software device TX queue cannot be used and packets will always be dropped once the macvtap driver queue fills up. This shouldn't be a great problem for the scenario where macvtap is used to feed a kvm receiver, as the traffic is most likely external in origin so congestion notification can't be applied anyway. Of course, if anybody decides to complain about guest-to-guest UDP packet loss down the track, then we may have to revisit this. Incidentally, this patch also fixes a real memory leak when macvtap_get_queue fails. Chris Wright noticed that for this patch to work, we need a non-zero TX queue length. This patch includes his work to change the default macvtap TX queue length to 500. Reported-by: Mark Wagner <mwagner@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Chris Wright <chrisw@sous-sol.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/macvlan.c10
-rw-r--r--drivers/net/macvtap.c18
2 files changed, 24 insertions, 4 deletions
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 87e8d4cb405..f15fe2cf72a 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -499,7 +499,7 @@ static const struct net_device_ops macvlan_netdev_ops = {
.ndo_validate_addr = eth_validate_addr,
};
-static void macvlan_setup(struct net_device *dev)
+void macvlan_common_setup(struct net_device *dev)
{
ether_setup(dev);
@@ -508,6 +508,12 @@ static void macvlan_setup(struct net_device *dev)
dev->destructor = free_netdev;
dev->header_ops = &macvlan_hard_header_ops,
dev->ethtool_ops = &macvlan_ethtool_ops;
+}
+EXPORT_SYMBOL_GPL(macvlan_common_setup);
+
+static void macvlan_setup(struct net_device *dev)
+{
+ macvlan_common_setup(dev);
dev->tx_queue_len = 0;
}
@@ -705,7 +711,6 @@ int macvlan_link_register(struct rtnl_link_ops *ops)
/* common fields */
ops->priv_size = sizeof(struct macvlan_dev);
ops->get_tx_queues = macvlan_get_tx_queues;
- ops->setup = macvlan_setup;
ops->validate = macvlan_validate;
ops->maxtype = IFLA_MACVLAN_MAX;
ops->policy = macvlan_policy;
@@ -719,6 +724,7 @@ EXPORT_SYMBOL_GPL(macvlan_link_register);
static struct rtnl_link_ops macvlan_link_ops = {
.kind = "macvlan",
+ .setup = macvlan_setup,
.newlink = macvlan_newlink,
.dellink = macvlan_dellink,
};
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index a8a94e2f6dd..ff02b836c3c 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -180,11 +180,18 @@ static int macvtap_forward(struct net_device *dev, struct sk_buff *skb)
{
struct macvtap_queue *q = macvtap_get_queue(dev, skb);
if (!q)
- return -ENOLINK;
+ goto drop;
+
+ if (skb_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len)
+ goto drop;
skb_queue_tail(&q->sk.sk_receive_queue, skb);
wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND);
- return 0;
+ return NET_RX_SUCCESS;
+
+drop:
+ kfree_skb(skb);
+ return NET_RX_DROP;
}
/*
@@ -235,8 +242,15 @@ static void macvtap_dellink(struct net_device *dev,
macvlan_dellink(dev, head);
}
+static void macvtap_setup(struct net_device *dev)
+{
+ macvlan_common_setup(dev);
+ dev->tx_queue_len = TUN_READQ_SIZE;
+}
+
static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
.kind = "macvtap",
+ .setup = macvtap_setup,
.newlink = macvtap_newlink,
.dellink = macvtap_dellink,
};