linux/drivers/net/macvlan.c

832 lines
21 KiB

macvlan: implement bridge, VEPA and private mode This allows each macvlan slave device to be in one of three modes, depending on the use case: MACVLAN_PRIVATE: The device never communicates with any other device on the same upper_dev. This even includes frames coming back from a reflective relay, where supported by the adjacent bridge. MACVLAN_VEPA: The new Virtual Ethernet Port Aggregator (VEPA) mode, we assume that the adjacent bridge returns all frames where both source and destination are local to the macvlan port, i.e. the bridge is set up as a reflective relay. Broadcast frames coming in from the upper_dev get flooded to all macvlan interfaces in VEPA mode. We never deliver any frames locally. MACVLAN_BRIDGE: We provide the behavior of a simple bridge between different macvlan interfaces on the same port. Frames from one interface to another one get delivered directly and are not sent out externally. Broadcast frames get flooded to all other bridge ports and to the external interface, but when they come back from a reflective relay, we don't deliver them again. Since we know all the MAC addresses, the macvlan bridge mode does not require learning or STP like the bridge module does. Based on an earlier patch "macvlan: Reflect macvlan packets meant for other macvlan devices" by Eric Biederman. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Patrick McHardy <kaber@trash.net> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-26 06:07:10 +00:00
macvlan: implement bridge, VEPA and private mode This allows each macvlan slave device to be in one of three modes, depending on the use case: MACVLAN_PRIVATE: The device never communicates with any other device on the same upper_dev. This even includes frames coming back from a reflective relay, where supported by the adjacent bridge. MACVLAN_VEPA: The new Virtual Ethernet Port Aggregator (VEPA) mode, we assume that the adjacent bridge returns all frames where both source and destination are local to the macvlan port, i.e. the bridge is set up as a reflective relay. Broadcast frames coming in from the upper_dev get flooded to all macvlan interfaces in VEPA mode. We never deliver any frames locally. MACVLAN_BRIDGE: We provide the behavior of a simple bridge between different macvlan interfaces on the same port. Frames from one interface to another one get delivered directly and are not sent out externally. Broadcast frames get flooded to all other bridge ports and to the external interface, but when they come back from a reflective relay, we don't deliver them again. Since we know all the MAC addresses, the macvlan bridge mode does not require learning or STP like the bridge module does. Based on an earlier patch "macvlan: Reflect macvlan packets meant for other macvlan devices" by Eric Biederman. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Patrick McHardy <kaber@trash.net> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-26 06:07:10 +00:00
macvlan: implement bridge, VEPA and private mode This allows each macvlan slave device to be in one of three modes, depending on the use case: MACVLAN_PRIVATE: The device never communicates with any other device on the same upper_dev. This even includes frames coming back from a reflective relay, where supported by the adjacent bridge. MACVLAN_VEPA: The new Virtual Ethernet Port Aggregator (VEPA) mode, we assume that the adjacent bridge returns all frames where both source and destination are local to the macvlan port, i.e. the bridge is set up as a reflective relay. Broadcast frames coming in from the upper_dev get flooded to all macvlan interfaces in VEPA mode. We never deliver any frames locally. MACVLAN_BRIDGE: We provide the behavior of a simple bridge between different macvlan interfaces on the same port. Frames from one interface to another one get delivered directly and are not sent out externally. Broadcast frames get flooded to all other bridge ports and to the external interface, but when they come back from a reflective relay, we don't deliver them again. Since we know all the MAC addresses, the macvlan bridge mode does not require learning or STP like the bridge module does. Based on an earlier patch "macvlan: Reflect macvlan packets meant for other macvlan devices" by Eric Biederman. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Patrick McHardy <kaber@trash.net> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-26 06:07:10 +00:00
macvlan: implement bridge, VEPA and private mode This allows each macvlan slave device to be in one of three modes, depending on the use case: MACVLAN_PRIVATE: The device never communicates with any other device on the same upper_dev. This even includes frames coming back from a reflective relay, where supported by the adjacent bridge. MACVLAN_VEPA: The new Virtual Ethernet Port Aggregator (VEPA) mode, we assume that the adjacent bridge returns all frames where both source and destination are local to the macvlan port, i.e. the bridge is set up as a reflective relay. Broadcast frames coming in from the upper_dev get flooded to all macvlan interfaces in VEPA mode. We never deliver any frames locally. MACVLAN_BRIDGE: We provide the behavior of a simple bridge between different macvlan interfaces on the same port. Frames from one interface to another one get delivered directly and are not sent out externally. Broadcast frames get flooded to all other bridge ports and to the external interface, but when they come back from a reflective relay, we don't deliver them again. Since we know all the MAC addresses, the macvlan bridge mode does not require learning or STP like the bridge module does. Based on an earlier patch "macvlan: Reflect macvlan packets meant for other macvlan devices" by Eric Biederman. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Patrick McHardy <kaber@trash.net> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-26 06:07:10 +00:00
macvlan: implement bridge, VEPA and private mode This allows each macvlan slave device to be in one of three modes, depending on the use case: MACVLAN_PRIVATE: The device never communicates with any other device on the same upper_dev. This even includes frames coming back from a reflective relay, where supported by the adjacent bridge. MACVLAN_VEPA: The new Virtual Ethernet Port Aggregator (VEPA) mode, we assume that the adjacent bridge returns all frames where both source and destination are local to the macvlan port, i.e. the bridge is set up as a reflective relay. Broadcast frames coming in from the upper_dev get flooded to all macvlan interfaces in VEPA mode. We never deliver any frames locally. MACVLAN_BRIDGE: We provide the behavior of a simple bridge between different macvlan interfaces on the same port. Frames from one interface to another one get delivered directly and are not sent out externally. Broadcast frames get flooded to all other bridge ports and to the external interface, but when they come back from a reflective relay, we don't deliver them again. Since we know all the MAC addresses, the macvlan bridge mode does not require learning or STP like the bridge module does. Based on an earlier patch "macvlan: Reflect macvlan packets meant for other macvlan devices" by Eric Biederman. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Patrick McHardy <kaber@trash.net> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-26 06:07:10 +00:00
macvlan: implement bridge, VEPA and private mode This allows each macvlan slave device to be in one of three modes, depending on the use case: MACVLAN_PRIVATE: The device never communicates with any other device on the same upper_dev. This even includes frames coming back from a reflective relay, where supported by the adjacent bridge. MACVLAN_VEPA: The new Virtual Ethernet Port Aggregator (VEPA) mode, we assume that the adjacent bridge returns all frames where both source and destination are local to the macvlan port, i.e. the bridge is set up as a reflective relay. Broadcast frames coming in from the upper_dev get flooded to all macvlan interfaces in VEPA mode. We never deliver any frames locally. MACVLAN_BRIDGE: We provide the behavior of a simple bridge between different macvlan interfaces on the same port. Frames from one interface to another one get delivered directly and are not sent out externally. Broadcast frames get flooded to all other bridge ports and to the external interface, but when they come back from a reflective relay, we don't deliver them again. Since we know all the MAC addresses, the macvlan bridge mode does not require learning or STP like the bridge module does. Based on an earlier patch "macvlan: Reflect macvlan packets meant for other macvlan devices" by Eric Biederman. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Patrick McHardy <kaber@trash.net> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-26 06:07:10 +00:00
macvlan: implement bridge, VEPA and private mode This allows each macvlan slave device to be in one of three modes, depending on the use case: MACVLAN_PRIVATE: The device never communicates with any other device on the same upper_dev. This even includes frames coming back from a reflective relay, where supported by the adjacent bridge. MACVLAN_VEPA: The new Virtual Ethernet Port Aggregator (VEPA) mode, we assume that the adjacent bridge returns all frames where both source and destination are local to the macvlan port, i.e. the bridge is set up as a reflective relay. Broadcast frames coming in from the upper_dev get flooded to all macvlan interfaces in VEPA mode. We never deliver any frames locally. MACVLAN_BRIDGE: We provide the behavior of a simple bridge between different macvlan interfaces on the same port. Frames from one interface to another one get delivered directly and are not sent out externally. Broadcast frames get flooded to all other bridge ports and to the external interface, but when they come back from a reflective relay, we don't deliver them again. Since we know all the MAC addresses, the macvlan bridge mode does not require learning or STP like the bridge module does. Based on an earlier patch "macvlan: Reflect macvlan packets meant for other macvlan devices" by Eric Biederman. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Patrick McHardy <kaber@trash.net> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-26 06:07:10 +00:00
macvlan: implement bridge, VEPA and private mode This allows each macvlan slave device to be in one of three modes, depending on the use case: MACVLAN_PRIVATE: The device never communicates with any other device on the same upper_dev. This even includes frames coming back from a reflective relay, where supported by the adjacent bridge. MACVLAN_VEPA: The new Virtual Ethernet Port Aggregator (VEPA) mode, we assume that the adjacent bridge returns all frames where both source and destination are local to the macvlan port, i.e. the bridge is set up as a reflective relay. Broadcast frames coming in from the upper_dev get flooded to all macvlan interfaces in VEPA mode. We never deliver any frames locally. MACVLAN_BRIDGE: We provide the behavior of a simple bridge between different macvlan interfaces on the same port. Frames from one interface to another one get delivered directly and are not sent out externally. Broadcast frames get flooded to all other bridge ports and to the external interface, but when they come back from a reflective relay, we don't deliver them again. Since we know all the MAC addresses, the macvlan bridge mode does not require learning or STP like the bridge module does. Based on an earlier patch "macvlan: Reflect macvlan packets meant for other macvlan devices" by Eric Biederman. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Patrick McHardy <kaber@trash.net> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-26 06:07:10 +00:00
macvlan: implement bridge, VEPA and private mode This allows each macvlan slave device to be in one of three modes, depending on the use case: MACVLAN_PRIVATE: The device never communicates with any other device on the same upper_dev. This even includes frames coming back from a reflective relay, where supported by the adjacent bridge. MACVLAN_VEPA: The new Virtual Ethernet Port Aggregator (VEPA) mode, we assume that the adjacent bridge returns all frames where both source and destination are local to the macvlan port, i.e. the bridge is set up as a reflective relay. Broadcast frames coming in from the upper_dev get flooded to all macvlan interfaces in VEPA mode. We never deliver any frames locally. MACVLAN_BRIDGE: We provide the behavior of a simple bridge between different macvlan interfaces on the same port. Frames from one interface to another one get delivered directly and are not sent out externally. Broadcast frames get flooded to all other bridge ports and to the external interface, but when they come back from a reflective relay, we don't deliver them again. Since we know all the MAC addresses, the macvlan bridge mode does not require learning or STP like the bridge module does. Based on an earlier patch "macvlan: Reflect macvlan packets meant for other macvlan devices" by Eric Biederman. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Patrick McHardy <kaber@trash.net> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-26 06:07:10 +00:00
macvlan: implement bridge, VEPA and private mode This allows each macvlan slave device to be in one of three modes, depending on the use case: MACVLAN_PRIVATE: The device never communicates with any other device on the same upper_dev. This even includes frames coming back from a reflective relay, where supported by the adjacent bridge. MACVLAN_VEPA: The new Virtual Ethernet Port Aggregator (VEPA) mode, we assume that the adjacent bridge returns all frames where both source and destination are local to the macvlan port, i.e. the bridge is set up as a reflective relay. Broadcast frames coming in from the upper_dev get flooded to all macvlan interfaces in VEPA mode. We never deliver any frames locally. MACVLAN_BRIDGE: We provide the behavior of a simple bridge between different macvlan interfaces on the same port. Frames from one interface to another one get delivered directly and are not sent out externally. Broadcast frames get flooded to all other bridge ports and to the external interface, but when they come back from a reflective relay, we don't deliver them again. Since we know all the MAC addresses, the macvlan bridge mode does not require learning or STP like the bridge module does. Based on an earlier patch "macvlan: Reflect macvlan packets meant for other macvlan devices" by Eric Biederman. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Patrick McHardy <kaber@trash.net> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-26 06:07:10 +00:00
macvlan: implement bridge, VEPA and private mode This allows each macvlan slave device to be in one of three modes, depending on the use case: MACVLAN_PRIVATE: The device never communicates with any other device on the same upper_dev. This even includes frames coming back from a reflective relay, where supported by the adjacent bridge. MACVLAN_VEPA: The new Virtual Ethernet Port Aggregator (VEPA) mode, we assume that the adjacent bridge returns all frames where both source and destination are local to the macvlan port, i.e. the bridge is set up as a reflective relay. Broadcast frames coming in from the upper_dev get flooded to all macvlan interfaces in VEPA mode. We never deliver any frames locally. MACVLAN_BRIDGE: We provide the behavior of a simple bridge between different macvlan interfaces on the same port. Frames from one interface to another one get delivered directly and are not sent out externally. Broadcast frames get flooded to all other bridge ports and to the external interface, but when they come back from a reflective relay, we don't deliver them again. Since we know all the MAC addresses, the macvlan bridge mode does not require learning or STP like the bridge module does. Based on an earlier patch "macvlan: Reflect macvlan packets meant for other macvlan devices" by Eric Biederman. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Patrick McHardy <kaber@trash.net> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-26 06:07:10 +00:00
macvlan: implement bridge, VEPA and private mode This allows each macvlan slave device to be in one of three modes, depending on the use case: MACVLAN_PRIVATE: The device never communicates with any other device on the same upper_dev. This even includes frames coming back from a reflective relay, where supported by the adjacent bridge. MACVLAN_VEPA: The new Virtual Ethernet Port Aggregator (VEPA) mode, we assume that the adjacent bridge returns all frames where both source and destination are local to the macvlan port, i.e. the bridge is set up as a reflective relay. Broadcast frames coming in from the upper_dev get flooded to all macvlan interfaces in VEPA mode. We never deliver any frames locally. MACVLAN_BRIDGE: We provide the behavior of a simple bridge between different macvlan interfaces on the same port. Frames from one interface to another one get delivered directly and are not sent out externally. Broadcast frames get flooded to all other bridge ports and to the external interface, but when they come back from a reflective relay, we don't deliver them again. Since we know all the MAC addresses, the macvlan bridge mode does not require learning or STP like the bridge module does. Based on an earlier patch "macvlan: Reflect macvlan packets meant for other macvlan devices" by Eric Biederman. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Patrick McHardy <kaber@trash.net> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-26 06:07:10 +00:00
macvlan: implement bridge, VEPA and private mode This allows each macvlan slave device to be in one of three modes, depending on the use case: MACVLAN_PRIVATE: The device never communicates with any other device on the same upper_dev. This even includes frames coming back from a reflective relay, where supported by the adjacent bridge. MACVLAN_VEPA: The new Virtual Ethernet Port Aggregator (VEPA) mode, we assume that the adjacent bridge returns all frames where both source and destination are local to the macvlan port, i.e. the bridge is set up as a reflective relay. Broadcast frames coming in from the upper_dev get flooded to all macvlan interfaces in VEPA mode. We never deliver any frames locally. MACVLAN_BRIDGE: We provide the behavior of a simple bridge between different macvlan interfaces on the same port. Frames from one interface to another one get delivered directly and are not sent out externally. Broadcast frames get flooded to all other bridge ports and to the external interface, but when they come back from a reflective relay, we don't deliver them again. Since we know all the MAC addresses, the macvlan bridge mode does not require learning or STP like the bridge module does. Based on an earlier patch "macvlan: Reflect macvlan packets meant for other macvlan devices" by Eric Biederman. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Patrick McHardy <kaber@trash.net> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-26 06:07:10 +00:00
drivers/net/macvlan.c: fix cloning of tagged VLAN interfaces Addresses http://bugzilla.kernel.org/show_bug.cgi?id=13348 akpm: the reporter disappeared, so I typed it in again. It is not possible to make clone of tagged VLAN interface to be used as mac-based vlan interfave. How reproducible: Use any 802.1q tagged vlan interface, e.g. eth2.700 and clone it: ip link add link eth2.700 address 00:04:75:cb:38:09 macvlan0 type macvlan ip link set dev macvlan0 up ip addr add 10.195.1.1/24 dev macvlan0 So far, so good. Now try to ping anything via macvlan0: ping 10.195.1.2 Actual results: For every attempted packet tx kernel writes to console: ------------[ cut here ]------------ WARNING: at net/8021q/vlan_dev.c:254 vlan_dev_hard_header+0x36/0x126 [8021q]() Hardware name: M22ES Modules linked in: arptable_filter arp_tables bridge veth macvlan arc4 ecb ppp_mppe ppp_async crc_ccitt ppp_generic slhc autofs4 sunrpc 8021q garp stp ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack xt_tcpudp x_tables dm_mirror dm_region_hash dm_log dm_multipath dm_mod sbs sbshc lp floppy snd_intel8x0 joydev snd_seq_dummy snd_intel8x0m snd_ac97_codec ide_cd_mod ac97_bus snd_seq_oss cdrom snd_seq_midi_event serio_raw snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss parport_pc snd_pcm parport battery 8139cp snd_timer i2c_sis96x ac button snd rtc_cmos rtc_core 8139too soundcore rtc_lib mii i2c_core pcspkr snd_page_alloc pata_sis libata sd_mod scsi_mod ext3 jbd ehci_hcd ohci_hcd uhci_hcd [last unloaded: ip_tables] Pid: 0, comm: swapper Tainted: G W 2.6.29.3 #1 Call Trace: [<c0425f48>] warn_slowpath+0x60/0x9f [<c0425f6f>] warn_slowpath+0x87/0x9f [<dffb850d>] vlan_dev_hard_header+0x0/0x126 [8021q] [<dffb8543>] vlan_dev_hard_header+0x36/0x126 [8021q] [<dffb850d>] vlan_dev_hard_header+0x0/0x126 [8021q] [<df83155d>] macvlan_hard_header+0x3c/0x47 [macvlan] [<df831521>] macvlan_hard_header+0x0/0x47 [macvlan] [<c062bf3f>] arp_create+0xef/0x1ff [<c062c08c>] arp_send+0x3d/0x54 [<c062c916>] arp_solicit+0x16c/0x177 [<c05fadd2>] neigh_timer_handler+0x227/0x269 [<c05fabab>] neigh_timer_handler+0x0/0x269 [<c042ce4d>] run_timer_softirq+0xf0/0x141 [<c0429e5a>] __do_softirq+0x76/0xf8 [<c0429de4>] __do_softirq+0x0/0xf8 <IRQ> [<c044fb67>] handle_level_irq+0x0/0xad [<c0429db7>] irq_exit+0x35/0x62 [<c04046bb>] do_IRQ+0xdf/0xf4 [<c04035a7>] common_interrupt+0x27/0x2c [<c04079c5>] default_idle+0x2a/0x3d [<c0401bb6>] cpu_idle+0x57/0x70 Macvlan driver always uses standard ethernet header length for all types of interface to which it is linked. This patch fixes this problem. Reported-by: <sg.tweak@gmail.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: "David S. Miller" <davem@davemloft.net> Cc: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-06-10 09:55:02 +00:00
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>
2010-07-21 21:44:31 +00:00
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>
2010-07-21 21:44:31 +00:00
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>
2010-07-21 21:44:31 +00:00