loopback current mtu of 16436 bytes allows no more than 3 MSS TCP
segments per frame, or 48 Kbytes. Changing mtu to 64K allows TCP
stack to build large frames and significantly reduces stack overhead.
Performance boost on bulk TCP transferts can be up to 30 %, partly
because we now have one ACK message for two 64KB segments, and a lower
probability of hitting /proc/sys/net/ipv4/tcp_reordering default limit.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As pointed out, there are places, that access net->loopback_dev->ifindex
and after ifindex generation is made per-net this value becomes constant
equals 1. So go ahead and introduce the LOOPBACK_IFINDEX constant and use
it where appropriate.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix race condition in several network drivers when reading stats on 32bit
UP architectures. These drivers update their stats in a BH context and
therefore should use u64_stats_fetch_begin_bh/u64_stats_fetch_retry_bh
instead of u64_stats_fetch_begin/u64_stats_fetch_retry when reading the
stats.
Signed-off-by: Kevin Groeneveld <kgroeneveld@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove all #inclusions of asm/system.h preparatory to splitting and killing
it. Performed with the following command:
perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`
Signed-off-by: David Howells <dhowells@redhat.com>
Only distinct use is checking if NETIF_F_NOCACHE_COPY should be
enabled by default. The check heuristics is altered a bit here,
so it hits other people than before. The default shouldn't be
trusted for performance-critical cases anyway.
For all other uses NETIF_F_NO_CSUM is equivalent to NETIF_F_HW_CSUM.
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch enables ethtool to set the loopback mode on a given interface.
By configuring the interface in loopback mode in conjunction with a policy
route / rule, a userland application can stress the egress / ingress path
exposing the flows of the change in progress and potentially help developer(s)
understand the impact of those changes without even sending a packet out
on the network.
Following set of commands illustrates one such example -
a) ip -4 addr add 192.168.1.1/24 dev eth1
b) ip -4 rule add from all iif eth1 lookup 250
c) ip -4 route add local 0/0 dev lo proto kernel scope host table 250
d) arp -Ds 192.168.1.100 eth1
e) arp -Ds 192.168.1.200 eth1
f) sysctl -w net.ipv4.ip_nonlocal_bind=1
g) sysctl -w net.ipv4.conf.all.accept_local=1
# Assuming that the machine has 8 cores
h) taskset 000f netserver -L 192.168.1.200
i) taskset 00f0 netperf -t TCP_CRR -L 192.168.1.100 -H 192.168.1.200 -l 30
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Several tests in the ipv6 routing code check IFF_LOOPBACK, and
allowing stacking such as VLAN'ing on top of loopback results in a
netdevice which reports IFF_LOOPBACK but really isn't the loopback
device.
Instead of spamming the ipv6 routing code with even more special tests,
simply disallow VLAN over loopback.
The result of this patch is:
# modprobe 8021q
# vconfig add lo 43
ERROR: trying to add VLAN #43 to IF -:lo:- error: Operation not supported
Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This also enables TSOv6, TSO-ECN, and UFO as loopback clearly can handle them.
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
In various situations, a device provides a packet to our stack and we
drop it before it enters protocol stack :
- softnet backlog full (accounted in /proc/net/softnet_stat)
- bad vlan tag (not accounted)
- unknown/unregistered protocol (not accounted)
We can handle a per-device counter of such dropped frames at core level,
and automatically adds it to the device provided stats (rx_dropped), so
that standard tools can be used (ifconfig, ip link, cat /proc/net/dev)
This is a generalization of commit 8990f468a (net: rx_dropped
accounting), thus reverting it.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
loopback driver uses dev->ml_priv to store its percpu stats pointer.
It uses ugly casts "(void __percpu __force *)" to shut up sparse
complains.
Define an union to better document we use ml_priv in loopback driver and
define a lstats field with appropriate types.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is a small possibility that a reader gets incorrect values on 32
bit arches. SNMP applications could catch incorrect counters when a
32bit high part is changed by another stats consumer/provider.
One way to solve this is to add a rtnl_link_stats64 param to all
ndo_get_stats64() methods, and also add such a parameter to
dev_get_stats().
Rule is that we are not allowed to use dev->stats64 as a temporary
storage for 64bit stats, but a caller provided area (usually on stack)
Old drivers (only providing get_stats() method) need no changes.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 6b10de38f0 (loopback: Implement 64bit stats on 32bit arches)
introduced 64bit stats in loopback driver, using a private seqcount and
private helpers.
David suggested to introduce a generic infrastructure, added in (net:
Introduce u64_stats_sync infrastructure)
This patch reimplements loopback 64bit stats using the u64_stats_sync
infrastructure.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Uses a seqcount_t to synchronize stat producer and consumer, for packets
and bytes counter, now u64 types.
(dropped counter being rarely used, stay a native "unsigned long" type)
No noticeable performance impact on x86, as it only adds two increments
per frame. It might be more expensive on arches where smp_wmb() is not
free.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add __percpu sparse annotations to net drivers.
These annotations are to make sparse consider percpu variables to be
in a different address space and warn if accessed without going
through percpu accessors. This patch doesn't affect normal builds.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (34 commits)
m68k: rename global variable vmalloc_end to m68k_vmalloc_end
percpu: add missing per_cpu_ptr_to_phys() definition for UP
percpu: Fix kdump failure if booted with percpu_alloc=page
percpu: make misc percpu symbols unique
percpu: make percpu symbols in ia64 unique
percpu: make percpu symbols in powerpc unique
percpu: make percpu symbols in x86 unique
percpu: make percpu symbols in xen unique
percpu: make percpu symbols in cpufreq unique
percpu: make percpu symbols in oprofile unique
percpu: make percpu symbols in tracer unique
percpu: make percpu symbols under kernel/ and mm/ unique
percpu: remove some sparse warnings
percpu: make alloc_percpu() handle array types
vmalloc: fix use of non-existent percpu variable in put_cpu_var()
this_cpu: Use this_cpu_xx in trace_functions_graph.c
this_cpu: Use this_cpu_xx for ftrace
this_cpu: Use this_cpu_xx in nmi handling
this_cpu: Use this_cpu operations in RCU
this_cpu: Use this_cpu ops for VM statistics
...
Fix up trivial (famous last words) global per-cpu naming conflicts in
arch/x86/kvm/svm.c
mm/slab.c
Defer calling unregister_netdevice_queue to cleanup_net. It's simpler
and it allows the loopback device to land in the same batch as other
network devices.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Generated with the following semantic patch
@@
struct net *n1;
struct net *n2;
@@
- n1 == n2
+ net_eq(n1, n2)
@@
struct net *n1;
struct net *n2;
@@
- n1 != n2
+ !net_eq(n1, n2)
applied over {include,net,drivers/net}.
Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use this_cpu_ptr and __this_cpu_ptr in locations where straight
transformations are possible because per_cpu_ptr is used with
either smp_processor_id() or raw_smp_processor_id().
cc: David Howells <dhowells@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
cc: Ingo Molnar <mingo@elte.hu>
cc: Rusty Russell <rusty@rustcorp.com.au>
cc: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
In a couple of cases collapse some extra code like:
int retval = NETDEV_TX_OK;
...
return retval;
into
return NETDEV_TX_OK;
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch is the result of an automatic spatch transformation to convert
all ndo_start_xmit() return values of 0 to NETDEV_TX_OK.
Some occurences are missed by the automatic conversion, those will be
handled in a seperate patch.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
One point of contention in high network loads is the dst_release() performed
when a transmited skb is freed. This is because NIC tx completion calls
dev_kree_skb() long after original call to dev_queue_xmit(skb).
CPU cache is cold and the atomic op in dst_release() stalls. On SMP, this is
quite visible if one CPU is 100% handling softirqs for a network device,
since dst_clone() is done by other cpus, involving cache line ping pongs.
It seems right place to release dst is in dev_hard_start_xmit(), for most
devices but ones that are virtual, and some exceptions.
David Miller suggested to define a new device flag, set in alloc_netdev_mq()
(so that most devices set it at init time), and carefuly unset in devices
which dont want a NULL skb->dst in their ndo_start_xmit().
List of devices that must clear this flag is :
- loopback device, because it calls netif_rx() and quoting Patrick :
"ip_route_input() doesn't accept loopback addresses, so loopback packets
already need to have a dst_entry attached."
- appletalk/ipddp.c : needs skb->dst in its xmit function
- And all devices that call again dev_queue_xmit() from their xmit function
(as some classifiers need skb->dst) : bonding, vlan, macvlan, eql, ifb, hdlc_fr
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We can in some situations drop packets in netif_rx()
loopback driver does not report these (unlikely) drops to its stats,
and incorrectly change packets/bytes counts.
After this patch applied, "ifconfig lo" can reports these drops as in :
# ifconfig lo
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:692562900 errors:3228 dropped:3228 overruns:0 frame:0
TX packets:692562900 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2865674174 (2.6 GiB) TX bytes:2865674174 (2.6 GiB)
I initialy chose to reflect those errors only in tx_dropped/tx_errors, but David
convinced me that it was really RX errors, as loopback_xmit() really starts
a RX process. (calling eth_type_trans() for example, that itself pulls the ethernet header)
These errors are accounted in rx_dropped/rx_errors.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch moves neigh_setup and hard_start_xmit into the network device ops
structure. For bisection, fix all the previously converted drivers as well.
Bonding driver took the biggest hit on this.
Added a prefetch of the hard_start_xmit in the fast path to try and reduce
any impact this would have.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
First device to convert over is the loopback device.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I was recently hunting a bug that occurred in network namespace
cleanup. In looking at the code it became apparrent that we have
and will continue to have cases where if we have anything going
on in a network namespace there will be assumptions that the
loopback device is present. Things like sending igmp unsubscribe
messages when we bring down network devices invokes the routing
code which assumes that at least the loopback driver is present.
Therefore to avoid magic initcall ordering hackery that is hard
to follow and hard to get right insert a call to register the
loopback device directly from net_dev_init(). This guarantes
that the loopback device is the first device registered and
the last network device to go away.
But do it carefully so we register the loopback device after
we clear dev_boot_phase.
Signed-off-by: Eric W. Biederman <ebiederm@maxwell.aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I was recently hunting a bug that occurred in network namespace
cleanup. In looking at the code it became apparrent that we have
and will continue to have cases where if we have anything going
on in a network namespace there will be assumptions that the
loopback device is present. Things like sending igmp unsubscribe
messages when we bring down network devices invokes the routing
code which assumes that at least the loopback driver is present.
Therefore to avoid magic initcall ordering hackery that is hard
to follow and hard to get right insert a call to register the
loopback device directly from net_dev_init(). This guarantes
that the loopback device is the first device registered and
the last network device to go away.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The generic packet receive code takes care of setting
netdev->last_rx when necessary, for the sake of the
bonding ARP monitor.
Drivers need not do it any more.
Some cases had to be skipped over because the drivers
were making use of the ->last_rx value themselves.
Signed-off-by: David S. Miller <davem@davemloft.net>
As noticed by Saikiran Madugula, commit 7447ef63cf
("loopback: Remove rest of LOOPBACK_TSO code.") got rid of
emulate_large_send_offload() but didn't get rid of the call
site as well.
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that the network stack can handle inbound packets with partial
checksums, we should no longer clobber the ip_summed field in the
loopback driver. This is because CHECKSUM_UNNECESSARY implies that
the checksum field is actually valid which is not true for loopback
packets since it's only partial (and thus complemented).
This allows packets from lo to then be SNATed to an external source
while still preserving the checksum's validity.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
It hasn't been enabled for a long time and the generic GSO
engine is better documentation of what is expected of a
device implementing TSO.
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch enables TSO since the loopback device is naturally
capable of handling packets of any size. This also means that
we won't enable GSO on lo which is good until GSO is fixed to
preserve netfilter state as netfilter treats loopback packets
in a special way.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The private area of a netdev is now at a fixed offset once more.
Unfortunately, some assumptions that netdev_priv() == netdev->priv
crept back into the tree. In particular this happened in the
loopback driver. Make it use netdev->ml_priv.
Signed-off-by: David S. Miller <davem@davemloft.net>
Introduce per-net_device inlines: dev_net(), dev_net_set().
Without CONFIG_NET_NS, no namespace other than &init_net exists.
Let's explicitly define them to help compiler optimizations.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
The LOOPBACK_OVERHEAD is not used in this file at all.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is probably a result of the changes from commit
854d836 - [NET]: Dynamically allocate the loopback device, part 2
Signed-off-by: Emil Medve <Emilian.Medve@Freescale.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
This patch reverts Eric's commit 2b008b0a8e
It diets .text & .data section of the kernel if CONFIG_NET_NS is not set.
This is safe after list operations cleanup.
Signed-of-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is not safe to to place struct pernet_operations in a special section.
We need struct pernet_operations to last until we call unregister_pernet_subsys.
Which doesn't happen until module unload.
So marking struct pernet_operations is a disaster for modules in two ways.
- We discard it before we call the exit method it points to.
- Because I keep struct pernet_operations on a linked list discarding
it for compiled in code removes elements in the middle of a linked
list and does horrible things for linked insert.
So this looks safe assuming __exit_refok is not discarded
for modules.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When the loopback device is failed to initialize inside the new
namespaces, panic() is called. Do not do it when the namespace
in question is not the init_net.
Plus cleanup the error path a bit.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
With the net namespaces many code leaved the __init section,
thus making the kernel occupy more memory than it did before.
Since we have a config option that prohibits the namespace
creation, the functions that initialize/finalize some netns
stuff are simply not needed and can be freed after the boot.
Currently, this is almost not noticeable, since few calls
are no longer in __init, but when the namespaces will be
merged it will be possible to free more code. I propose to
use the __net_init, __net_exit and __net_initdata "attributes"
for functions/variables that are not used if the CONFIG_NET_NS
is not set to save more space in memory.
The exiting functions cannot just reside in the __exit section,
as noticed by David, since the init section will have
references on it and the compilation will fail due to modpost
checks. These references can exist, since the init namespace
never dies and the exit callbacks are never called. So I
introduce the __exit_refok attribute just like it is already
done with the __init_refok.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
A hint as to why it is safe to use per cpu variables,
and note that we actually can have multiple instances
of the loopback device now.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Loopback device is special. It should be initialized at the very
beginning. Initialization order has been changed by
Eric W. Biederman <ebiederm@xmission.com> and this change is non-obvious
and important enough to add proper comment.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since hardware header operations are part of the protocol class
not the device instance, make them into a separate object and
save memory.
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch makes loopback_dev per network namespace. Adding
code to create a different loopback device for each network
namespace and adding the code to free a loopback device
when a network namespace exits.
This patch modifies all users the loopback_dev so they
access it as init_net.loopback_dev, keeping all of the
code compiling and working. A later pass will be needed to
update the users to use something other than the initial network
namespace.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch add support for dynamically allocating the statistics counters
for the loopback device and adds appropriate device methods for allocating
and freeing the loopback device.
This completes support for creating multiple instances of the loopback
device, in preparation for creating per network namespace instances.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Doing this makes loopback.c a better example of how to do a
simple network device, and it removes the special case
single static allocation of a struct net_device, hopefully
making maintenance easier.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-By: Kirill Korotaev <dev@sw.ru>
Acked-by: Benjamin Thery <benjamin.thery@bull.net>
This patch replaces all occurences to the static variable
loopback_dev to a pointer loopback_dev. That provides the
mindless, trivial, uninteressting change part for the dynamic
allocation for the loopback.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-By: Kirill Korotaev <dev@sw.ru>
Acked-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
For the operations
get-tx-csum
get-sg
get-tso
get-ufo
the default ethtool_op_xxx behavior is fine for all drivers, so we
permit op==NULL to imply the default behavior.
This provides a more uniform behavior across all drivers, eliminating
ethtool(8) "ioctl not supported" errors on older drivers that had
not been updated for the latest sub-ioctls.
The ethtool_op_xxx() functions are left exported, in case anyone
wishes to call them directly from a driver-private implementation --
a not-uncommon case. Should an ethtool_op_xxx() helper remain unused
for a while, except by net/core/ethtool.c, we can un-export it at a
later date.
[ Resolved conflicts with set/get value ethtool patch... -DaveM ]
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The core patchset of the network namespace sent by
Eric Biederman does not do dynamic loopback creation.
So there is no call to alloc_netdev_mq which fills the
network namespace field of the netdevice.
This patch assign the loopback to the init network namespace.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
