8a35747a5d
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>
94 lines
2.4 KiB
C
94 lines
2.4 KiB
C
#ifndef _LINUX_IF_MACVLAN_H
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#define _LINUX_IF_MACVLAN_H
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#include <linux/if_link.h>
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#include <linux/list.h>
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#include <linux/netdevice.h>
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#include <linux/netlink.h>
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#include <net/netlink.h>
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#if defined(CONFIG_MACVTAP) || defined(CONFIG_MACVTAP_MODULE)
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struct socket *macvtap_get_socket(struct file *);
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#else
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#include <linux/err.h>
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#include <linux/errno.h>
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struct file;
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struct socket;
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static inline struct socket *macvtap_get_socket(struct file *f)
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{
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return ERR_PTR(-EINVAL);
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}
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#endif /* CONFIG_MACVTAP */
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struct macvlan_port;
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struct macvtap_queue;
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/**
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* struct macvlan_rx_stats - MACVLAN percpu rx stats
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* @rx_packets: number of received packets
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* @rx_bytes: number of received bytes
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* @multicast: number of received multicast packets
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* @rx_errors: number of errors
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*/
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struct macvlan_rx_stats {
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unsigned long rx_packets;
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unsigned long rx_bytes;
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unsigned long multicast;
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unsigned long rx_errors;
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};
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struct macvlan_dev {
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struct net_device *dev;
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struct list_head list;
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struct hlist_node hlist;
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struct macvlan_port *port;
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struct net_device *lowerdev;
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struct macvlan_rx_stats __percpu *rx_stats;
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enum macvlan_mode mode;
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int (*receive)(struct sk_buff *skb);
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int (*forward)(struct net_device *dev, struct sk_buff *skb);
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struct macvtap_queue *tap;
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};
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static inline void macvlan_count_rx(const struct macvlan_dev *vlan,
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unsigned int len, bool success,
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bool multicast)
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{
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struct macvlan_rx_stats *rx_stats;
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rx_stats = per_cpu_ptr(vlan->rx_stats, smp_processor_id());
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if (likely(success)) {
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rx_stats->rx_packets++;;
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rx_stats->rx_bytes += len;
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if (multicast)
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rx_stats->multicast++;
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} else {
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rx_stats->rx_errors++;
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}
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}
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extern void macvlan_common_setup(struct net_device *dev);
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extern int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
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struct nlattr *tb[], struct nlattr *data[],
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int (*receive)(struct sk_buff *skb),
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int (*forward)(struct net_device *dev,
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struct sk_buff *skb));
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extern void macvlan_count_rx(const struct macvlan_dev *vlan,
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unsigned int len, bool success,
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bool multicast);
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extern void macvlan_dellink(struct net_device *dev, struct list_head *head);
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extern int macvlan_link_register(struct rtnl_link_ops *ops);
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extern netdev_tx_t macvlan_start_xmit(struct sk_buff *skb,
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struct net_device *dev);
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extern struct sk_buff *(*macvlan_handle_frame_hook)(struct macvlan_port *,
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struct sk_buff *);
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#endif /* _LINUX_IF_MACVLAN_H */
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