This patch adds the helper skb_gro_receive to merge packets for
GRO. The current method is to allocate a new header skb and then
chain the original packets to its frag_list. This is done to
make it easier to integrate into the existing GSO framework.
In future as GSO is moved into the drivers, we can undo this and
simply chain the original packets together.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
During SACK processing, most of the benefits of TSO are eaten by
the SACK blocks that one-by-one fragment SKBs to MSS sized chunks.
Then we're in problems when cleanup work for them has to be done
when a large cumulative ACK comes. Try to return back to pre-split
state already while more and more SACK info gets discovered by
combining newly discovered SACK areas with the previous skb if
that's SACKed as well.
This approach has a number of benefits:
1) The processing overhead is spread more equally over the RTT
2) Write queue has less skbs to process (affect everything
which has to walk in the queue past the sacked areas)
3) Write queue is consistent whole the time, so no other parts
of TCP has to be aware of this (this was not the case with
some other approach that was, well, quite intrusive all
around).
4) Clean_rtx_queue can release most of the pages using single
put_page instead of previous PAGE_SIZE/mss+1 calls
In case a hole is fully filled by the new SACK block, we attempt
to combine the next skb too which allows construction of skbs
that are even larger than what tso split them to and it handles
hole per on every nth patterns that often occur during slow start
overshoot pretty nicely. Though this to be really useful also
a retransmission would have to get lost since cumulative ACKs
advance one hole at a time in the most typical case.
TODO: handle upwards only merging. That should be rather easy
when segment is fully sacked but I'm leaving that as future
work item (it won't make very large difference anyway since
this current approach already covers quite a lot of normal
cases).
I was earlier thinking of some sophisticated way of tracking
timestamps of the first and the last segment but later on
realized that it won't be that necessary at all to store the
timestamp of the last segment. The cases that can occur are
basically either:
1) ambiguous => no sensible measurement can be taken anyway
2) non-ambiguous is due to reordering => having the timestamp
of the last segment there is just skewing things more off
than does some good since the ack got triggered by one of
the holes (besides some substle issues that would make
determining right hole/skb even harder problem). Anyway,
it has nothing to do with this change then.
I choose to route some abnormal looking cases with goto noop,
some could be handled differently (eg., by stopping the
walking at that skb but again). In general, they either
shouldn't happen at all or are rare enough to make no difference
in practice.
In theory this change (as whole) could cause some macroscale
regression (global) because of cache misses that are taken over
the round-trip time but it gets very likely better because of much
less (local) cache misses per other write queue walkers and the
big recovery clearing cumulative ack.
Worth to note that these benefits would be very easy to get also
without TSO/GSO being on as long as the data is in pages so that
we can merge them. Currently I won't let that happen because
DSACK splitting at fragment that would mess up pcounts due to
sk_can_gso in tcp_set_skb_tso_segs. Once DSACKs fragments gets
avoided, we have some conditions that can be made less strict.
TODO: I will probably have to convert the excessive pointer
passing to struct sacktag_state... :-)
My testing revealed that considerable amount of skbs couldn't
be shifted because they were cloned (most likely still awaiting
tx reclaim)...
[The rest is considering future work instead since I got
repeatably EFAULT to tcpdump's recvfrom when I added
pskb_expand_head to deal with clones, so I separated that
into another, later patch]
...To counter that, I gave up on the fifth advantage:
5) When growing previous SACK block, less allocs for new skbs
are done, basically a new alloc is needed only when new hole
is detected and when the previous skb runs out of frags space
...which now only happens of if reclaim is fast enough to dispose
the clone before the SACK block comes in (the window is RTT long),
otherwise we'll have to alloc some.
With clones being handled I got these numbers (will be somewhat
worse without that), taken with fine-grained mibs:
TCPSackShifted 398
TCPSackMerged 877
TCPSackShiftFallback 320
TCPSACKCOLLAPSEFALLBACKGSO 0
TCPSACKCOLLAPSEFALLBACKSKBBITS 0
TCPSACKCOLLAPSEFALLBACKSKBDATA 0
TCPSACKCOLLAPSEFALLBACKBELOW 0
TCPSACKCOLLAPSEFALLBACKFIRST 1
TCPSACKCOLLAPSEFALLBACKPREVBITS 318
TCPSACKCOLLAPSEFALLBACKMSS 1
TCPSACKCOLLAPSEFALLBACKNOHEAD 0
TCPSACKCOLLAPSEFALLBACKSHIFT 0
TCPSACKCOLLAPSENOOPSEQ 0
TCPSACKCOLLAPSENOOPSMALLPCOUNT 0
TCPSACKCOLLAPSENOOPSMALLLEN 0
TCPSACKCOLLAPSEHOLE 12
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Wireless HW without any dedicated queues for aggregation
do not need the ampdu_queues mechanism present right now
in mac80211. Since mac80211 is still incomplete wrt TX MQ
changes, do not allow aggregation sessions for drivers that
set ampdu_queues.
This is only an interim hack until Intel fixes the requeue issue.
Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: Luis Rodriguez <Luis.Rodriguez@Atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Add some packet-split receive hooks.
For one this allows to do NUMA node affine page allocs. Later on these
hooks will be extended to do emergency reserve allocations for
fragments.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds skb_recycle_check(), which can be used by a network
driver after transmitting an skb to check whether this skb can be
recycled as a receive buffer.
skb_recycle_check() checks that the skb is not shared or cloned, and
that it is linear and its head portion large enough (as determined by
the driver) to be recycled as a receive buffer. If these conditions
are met, it does any necessary reference count dropping and cleans
up the skbuff as if it just came from __alloc_skb().
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
A lot of code wants to iterate over an SKB queue at the top level using
it's own control structure and iterator scheme.
Provide skb_queue_next(), which is only valid to invoke if
skb_queue_is_last() returns false.
Signed-off-by: David S. Miller <davem@davemloft.net>
Several bits of code want to know "is this the last SKB in
a queue", and all of them implement this by hand.
Provide an common interface to make this check.
Signed-off-by: David S. Miller <davem@davemloft.net>
Handle the case of head being non-empty, by adding list->qlen
to head->qlen instead of using direct assignment.
Signed-off-by: David S. Miller <davem@davemloft.net>
There's an skb_copy_datagram_iovec() to copy out of a paged skb, but
nothing the other way around (because we don't do that).
We want to allocate big skbs in tun.c, so let's add the function.
It's a carbon copy of skb_copy_datagram_iovec() with enough changes to
be annoying.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Inserting a space between the `-' improved the C readability (some languages
allow hyphens within functions and variable names, which is confusing).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add missing kernel-doc notation to sk_buff:
Warning(linux-2.6.27-rc1-git2//include/linux/skbuff.h:345): No description found for parameter 'do_not_encrypt'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixes mac80211 to not use the skb->cb over the queue step
from virtual interfaces to the master. The patch also, for now,
disables aggregation because that would still require requeuing,
will fix that in a separate patch. There are two other places (software
requeue and powersaving stations) where requeue can happen, but that is
not currently used by any drivers/not possible to use respectively.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Use a real skb member to store the skb to avoid clashes with qdiscs,
which are allowed to use the cb area themselves. As currently only real
devices that consume the skb set the NETIF_F_HW_VLAN_TX flag, no explicit
invalidation is neccessary.
The new member fills a hole on 64 bit, the skb layout changes from:
__u32 mark; /* 172 4 */
sk_buff_data_t transport_header; /* 176 4 */
sk_buff_data_t network_header; /* 180 4 */
sk_buff_data_t mac_header; /* 184 4 */
sk_buff_data_t tail; /* 188 4 */
/* --- cacheline 3 boundary (192 bytes) --- */
sk_buff_data_t end; /* 192 4 */
/* XXX 4 bytes hole, try to pack */
to
__u32 mark; /* 172 4 */
__u16 vlan_tci; /* 176 2 */
/* XXX 2 bytes hole, try to pack */
sk_buff_data_t transport_header; /* 180 4 */
sk_buff_data_t network_header; /* 184 4 */
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add skb_warn_if_lro() to test whether an skb was received with LRO and
warn if so.
Change br_forward(), ip_forward() and ip6_forward() to call it) and
discard the skb if it returns true.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add kernel-doc notation for ndisc_nodetype:
Warning(linux-2.6.25-git2//include/linux/skbuff.h:340): No description found for parameter 'ndisc_nodetype'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This expresses __skb_queue_tail() in terms of __skb_insert(),
using __skb_insert_before() as auxiliary function.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This expresses __skb_append in terms of __skb_queue_after, exploiting that
__skb_append(old, new, list) = __skb_queue_after(list, old, new).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
By reordering, __skb_queue_after() is expressed in terms of __skb_insert().
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
By rearranging the order of declarations, __skb_dequeue() is expressed in terms of
* skb_peek() and
* __skb_unlink(),
thus in effect mirroring the analogue implementation of __skb_dequeue_tail().
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch updates the Linux the Intra-Site Automatic Tunnel Addressing
Protocol (ISATAP) implementation. It places the ISATAP potential router
list (PRL) in the kernel and adds three new private ioctls for PRL
management.
[Add several changes of structure name, constant names etc. - yoshfuji]
Signed-off-by: Fred L. Templin <fred.l.templin@boeing.com>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
(Anonymous) unions can help us to avoid ugly casts.
A common cast it the (struct rtable *)skb->dst one.
Defining an union like :
union {
struct dst_entry *dst;
struct rtable *rtable;
};
permits to use skb->rtable in place.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add missing structure kernel-doc descriptions to sock.h & skbuff.h
to fix kernel-doc warnings.
(I think that Stephen H. sent a similar patch, but I can't find it.
I just want to kill the warnings, with either patch.)
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use it in virtio_net (replacing buggy version there), it's also going
to be used by TAP for partial csum support.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: David S. Miller <davem@davemloft.net>
Before the removal of the deferred output hooks, netoutdev was used in
case of VLANs on top of a bridge to store the VLAN device, so the
deferred hooks would see the correct output device. This isn't
necessary anymore since we're calling the output hooks for the correct
device directly in the IP stack.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
The previous move of the the UDP inDatagrams counter caused each
peek of the same packet to be counted separately. This may be
undesirable.
This patch fixes this by adding a bit to sk_buff to record whether
this packet has already been seen through skb_recv_datagram. We
then only increment the counter when the packet is seen for the
first time.
The only dodgy part is the fact that skb_recv_datagram doesn't have
a good way of returning this new bit of information. So I've added
a new function __skb_recv_datagram that does return this and made
skb_recv_datagram a wrapper around it.
The plan is to eventually replace all uses of skb_recv_datagram with
this new function at which time it can be renamed its proper name.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently it is possible for two processes to peek on the same socket
and end up incrementing the error counter twice for the same packet.
This patch fixes it by making skb_kill_datagram return whether it
succeeded in unlinking the packet and only incrementing the counter
if it did.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The skb_morph function only freed the data part of the dst skb, but leaked
the auxiliary data such as the netfilter fields. This patch fixes this by
moving the relevant parts from __kfree_skb to skb_release_all and calling
it in skb_morph.
It also makes kfree_skbmem static since it's no longer called anywhere else
and it now no longer does skb_release_data.
Thanks to Yasuyuki KOZAKAI for finding this problem and posting a patch for
it.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The intent of the assertion in skb_truesize_check() is to check
for skb->truesize being decremented too much by other code,
resulting in a wraparound below zero.
The type of the right side of the comparison causes the compiler to
promote the left side to an unsigned type, despite the presence of an
explicit type cast. This defeats the check for negativity.
Ensure both sides of the comparison are a signed type to prevent the
implicit type conversion.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In some places, the result of skb_headroom() is compared to an unsigned
integer, and in others, the result is compared to a signed integer. Make
the comparisons consistent and correct.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Just hide it behind the #ifdef, because nobody wants
it now.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make the helper for getting the field, symmetrical to
the "set" one. Return 0 if CONFIG_NETDEVICES_MULTIQUEUE=n
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The calculation in SKB_WITH_OVERHEAD is incorrect in that it can cause
an overflow across a page boundary which is what it's meant to prevent.
In particular, the header length (X) should not be lumped together with
skb_shared_info. The latter needs to be aligned properly while the header
has no choice but to sit in front of wherever the payload is.
Therefore the correct calculation is to take away the aligned size of
skb_shared_info, and then subtract the header length. The resulting
quantity L satisfies the following inequality:
SKB_DATA_ALIGN(L + X) + sizeof(struct skb_shared_info) <= PAGE_SIZE
This is the quantity used by alloc_skb to do the actual allocation.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6: (42 commits)
[IPV6]: Consolidate the ip6_pol_route_(input|output) pair
[TCP]: Make snd_cwnd_cnt 32-bit
[TCP]: Update the /proc/net/tcp documentation
[NETNS]: Don't panic on creating the namespace's loopback
[NEIGH]: Ensure that pneigh_lookup is protected with RTNL
[INET]: kmalloc+memset -> kzalloc in frag_alloc_queue
[ISDN]: Fix compile with CONFIG_ISDN_X25 disabled.
[IPV6]: Replace sk_buff ** with sk_buff * in input handlers
[SELINUX]: Update for netfilter ->hook() arg changes.
[INET]: Consolidate the xxx_put
[INET]: Small cleanup for xxx_put after evictor consolidation
[INET]: Consolidate the xxx_evictor
[INET]: Consolidate the xxx_frag_destroy
[INET]: Consolidate xxx_the secret_rebuild
[INET]: Consolidate the xxx_frag_kill
[INET]: Collect common frag sysctl variables together
[INET]: Collect frag queues management objects together
[INET]: Move common fields from frag_queues in one place.
[TG3]: Fix performance regression on 5705.
[ISDN]: Remove local copy of device name to make sure renames work.
...
This patch creates a new function skb_morph that's just like skb_clone
except that it lets user provide the spare skb that will be overwritten
by the one that's to be cloned.
This will be used by IP fragment reassembly so that we get back the same
skb that went in last (rather than the head skb that we get now which
requires us to carry around double pointers all over the place).
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds an optimised version of skb_cow that avoids the copy if
the header can be modified even if the rest of the payload is cloned.
This can be used in encapsulating paths where we only need to modify the
header. As it is, this can be used in PPPOE and bridging.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
