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Commit Graph

209 Commits

Author SHA1 Message Date
Tom Herbert
0a9627f264 rps: Receive Packet Steering
This patch implements software receive side packet steering (RPS).  RPS
distributes the load of received packet processing across multiple CPUs.

Problem statement: Protocol processing done in the NAPI context for received
packets is serialized per device queue and becomes a bottleneck under high
packet load.  This substantially limits pps that can be achieved on a single
queue NIC and provides no scaling with multiple cores.

This solution queues packets early on in the receive path on the backlog queues
of other CPUs.   This allows protocol processing (e.g. IP and TCP) to be
performed on packets in parallel.   For each device (or each receive queue in
a multi-queue device) a mask of CPUs is set to indicate the CPUs that can
process packets. A CPU is selected on a per packet basis by hashing contents
of the packet header (e.g. the TCP or UDP 4-tuple) and using the result to index
into the CPU mask.  The IPI mechanism is used to raise networking receive
softirqs between CPUs.  This effectively emulates in software what a multi-queue
NIC can provide, but is generic requiring no device support.

Many devices now provide a hash over the 4-tuple on a per packet basis
(e.g. the Toeplitz hash).  This patch allow drivers to set the HW reported hash
in an skb field, and that value in turn is used to index into the RPS maps.
Using the HW generated hash can avoid cache misses on the packet when
steering it to a remote CPU.

The CPU mask is set on a per device and per queue basis in the sysfs variable
/sys/class/net/<device>/queues/rx-<n>/rps_cpus.  This is a set of canonical
bit maps for receive queues in the device (numbered by <n>).  If a device
does not support multi-queue, a single variable is used for the device (rx-0).

Generally, we have found this technique increases pps capabilities of a single
queue device with good CPU utilization.  Optimal settings for the CPU mask
seem to depend on architectures and cache hierarcy.  Below are some results
running 500 instances of netperf TCP_RR test with 1 byte req. and resp.
Results show cumulative transaction rate and system CPU utilization.

e1000e on 8 core Intel
   Without RPS: 108K tps at 33% CPU
   With RPS:    311K tps at 64% CPU

forcedeth on 16 core AMD
   Without RPS: 156K tps at 15% CPU
   With RPS:    404K tps at 49% CPU

bnx2x on 16 core AMD
   Without RPS  567K tps at 61% CPU (4 HW RX queues)
   Without RPS  738K tps at 96% CPU (8 HW RX queues)
   With RPS:    854K tps at 76% CPU (4 HW RX queues)

Caveats:
- The benefits of this patch are dependent on architecture and cache hierarchy.
Tuning the masks to get best performance is probably necessary.
- This patch adds overhead in the path for processing a single packet.  In
a lightly loaded server this overhead may eliminate the advantages of
increased parallelism, and possibly cause some relative performance degradation.
We have found that masks that are cache aware (share same caches with
the interrupting CPU) mitigate much of this.
- The RPS masks can be changed dynamically, however whenever the mask is changed
this introduces the possibility of generating out of order packets.  It's
probably best not change the masks too frequently.

Signed-off-by: Tom Herbert <therbert@google.com>

 include/linux/netdevice.h |   32 ++++-
 include/linux/skbuff.h    |    3 +
 net/core/dev.c            |  335 +++++++++++++++++++++++++++++++++++++--------
 net/core/net-sysfs.c      |  225 ++++++++++++++++++++++++++++++-
 net/core/skbuff.c         |    2 +
 5 files changed, 538 insertions(+), 59 deletions(-)
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-03-16 21:23:18 -07:00
Alexey Dobriyan
28dfef8feb const: constify remaining pipe_buf_operations
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:05 -08:00
Eric Dumazet
8964be4a9a net: rename skb->iif to skb->skb_iif
To help grep games, rename iif to skb_iif

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-20 15:35:04 -08:00
David S. Miller
3505d1a9fd Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
	drivers/net/sfc/sfe4001.c
	drivers/net/wireless/libertas/cmd.c
	drivers/staging/Kconfig
	drivers/staging/Makefile
	drivers/staging/rtl8187se/Kconfig
	drivers/staging/rtl8192e/Kconfig
2009-11-18 22:19:03 -08:00
Herbert Xu
69c0cab120 gro: Fix illegal merging of trailer trash
When we've merged skb's with page frags, and subsequently receive
a trailer skb (< MSS) that is not completely non-linear (this can
occur on Intel NICs if the packet size falls below the threshold),
GRO ends up producing an illegal GSO skb with a frag_list.

This is harmless unless the skb is then forwarded through an
interface that requires software GSO, whereupon the GSO code
will BUG.

This patch detects this case in GRO and avoids merging the
trailer skb.

Reported-by: Mark Wagner <mwagner@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-17 05:18:18 -08:00
Anton Vorontsov
e84af6ddef skbuff: Do not allow skb recycling with disabled IRQs
NAPI drivers try to recycle SKBs in their polling routine, but we
generally don't know the context in which the polling will be called,
and the skb recycling itself may require IRQs to be enabled.

This patch adds irqs_disabled() test to the skb_recycle_check()
routine, so that we'll not let the drivers hit the skb recycling
path with IRQs disabled.

As a side effect, this patch actually disables skb recycling for some
[broken] drivers. E.g. gianfar driver grabs an irqsave spinlock during
TX ring processing, and then tries to recycle an skb, and that caused
the following badness:

nf_conntrack version 0.5.0 (1008 buckets, 4032 max)
------------[ cut here ]------------
Badness at kernel/softirq.c:143
NIP: c003e3c4 LR: c423a528 CTR: c003e344
...
NIP [c003e3c4] local_bh_enable+0x80/0xc4
LR [c423a528] destroy_conntrack+0xd4/0x13c [nf_conntrack]
Call Trace:
[c15d1b60] [c003e32c] local_bh_disable+0x1c/0x34 (unreliable)
[c15d1b70] [c423a528] destroy_conntrack+0xd4/0x13c [nf_conntrack]
[c15d1b80] [c02c6370] nf_conntrack_destroy+0x3c/0x70

Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-11 19:03:28 -08:00
Johannes Berg
72bce62775 net: remove unused skb->do_not_encrypt
mac80211 required this due to the master netdev, but now
it can put all information into skb->cb and this can go.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-07-24 15:05:31 -04:00
Linus Torvalds
d2aa455037 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (55 commits)
  netxen: fix tx ring accounting
  netxen: fix detection of cut-thru firmware mode
  forcedeth: fix dma api mismatches
  atm: sk_wmem_alloc initial value is one
  net: correct off-by-one write allocations reports
  via-velocity : fix no link detection on boot
  Net / e100: Fix suspend of devices that cannot be power managed
  TI DaVinci EMAC : Fix rmmod error
  net: group address list and its count
  ipv4: Fix fib_trie rebalancing, part 2
  pkt_sched: Update drops stats in act_police
  sky2: version 1.23
  sky2: add GRO support
  sky2: skb recycling
  sky2: reduce default transmit ring
  sky2: receive counter update
  sky2: fix shutdown synchronization
  sky2: PCI irq issues
  sky2: more receive shutdown
  sky2: turn off pause during shutdown
  ...

Manually fix trivial conflict in net/core/skbuff.c due to kmemcheck
2009-06-18 14:07:15 -07:00
Stephen Hemminger
603a8bbe62 skbuff: don't corrupt mac_header on skb expansion
The skb mac_header field is sometimes NULL (or ~0u) as a sentinel
value. The places where skb is expanded add an offset which would
change this flag into an invalid pointer (or offset).

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-06-17 18:46:41 -07:00
Stephen Hemminger
19633e129c skbuff: skb_mac_header_was_set is always true on >32 bit
Looking at the crash in log_martians(), one suspect is that the check for
mac header being set is not correct.  The value of mac_header defaults to
0 on allocation, therefore skb_mac_header_was_set will always be true on
platforms using NET_SKBUFF_USES_OFFSET.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-06-17 18:46:03 -07:00
Linus Torvalds
b3fec0fe35 Merge branch 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/vegard/kmemcheck
* 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/vegard/kmemcheck: (39 commits)
  signal: fix __send_signal() false positive kmemcheck warning
  fs: fix do_mount_root() false positive kmemcheck warning
  fs: introduce __getname_gfp()
  trace: annotate bitfields in struct ring_buffer_event
  net: annotate struct sock bitfield
  c2port: annotate bitfield for kmemcheck
  net: annotate inet_timewait_sock bitfields
  ieee1394/csr1212: fix false positive kmemcheck report
  ieee1394: annotate bitfield
  net: annotate bitfields in struct inet_sock
  net: use kmemcheck bitfields API for skbuff
  kmemcheck: introduce bitfield API
  kmemcheck: add opcode self-testing at boot
  x86: unify pte_hidden
  x86: make _PAGE_HIDDEN conditional
  kmemcheck: make kconfig accessible for other architectures
  kmemcheck: enable in the x86 Kconfig
  kmemcheck: add hooks for the page allocator
  kmemcheck: add hooks for page- and sg-dma-mappings
  kmemcheck: don't track page tables
  ...
2009-06-16 13:09:51 -07:00
Vegard Nossum
fe55f6d5c0 net: use kmemcheck bitfields API for skbuff
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
2009-06-15 15:49:25 +02:00
David S. Miller
9cbc1cb8cd Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:
	Documentation/feature-removal-schedule.txt
	drivers/scsi/fcoe/fcoe.c
	net/core/drop_monitor.c
	net/core/net-traces.c
2009-06-15 03:02:23 -07:00
Linus Torvalds
8623661180 Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (244 commits)
  Revert "x86, bts: reenable ptrace branch trace support"
  tracing: do not translate event helper macros in print format
  ftrace/documentation: fix typo in function grapher name
  tracing/events: convert block trace points to TRACE_EVENT(), fix !CONFIG_BLOCK
  tracing: add protection around module events unload
  tracing: add trace_seq_vprint interface
  tracing: fix the block trace points print size
  tracing/events: convert block trace points to TRACE_EVENT()
  ring-buffer: fix ret in rb_add_time_stamp
  ring-buffer: pass in lockdep class key for reader_lock
  tracing: add annotation to what type of stack trace is recorded
  tracing: fix multiple use of __print_flags and __print_symbolic
  tracing/events: fix output format of user stack
  tracing/events: fix output format of kernel stack
  tracing/trace_stack: fix the number of entries in the header
  ring-buffer: discard timestamps that are at the start of the buffer
  ring-buffer: try to discard unneeded timestamps
  ring-buffer: fix bug in ring_buffer_discard_commit
  ftrace: do not profile functions when disabled
  tracing: make trace pipe recognize latency format flag
  ...
2009-06-10 19:53:40 -07:00
Johannes Berg
8f77f3849c mac80211: do not pass PS frames out of mac80211 again
In order to handle powersave frames properly we had needed
to pass these out to the device queues again, and introduce
the skb->requeue bit. This, however, also has unnecessary
overhead by needing to 'clean up' already tried frames, and
this clean-up code is also buggy when software encryption
is used.

Instead of sending the frames via the master netdev queue
again, simply put them into the pending queue. This also
fixes a problem where frames for that particular station
could be reordered when some were still on the software
queues and older ones are re-injected into the software
queue after them.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-06-10 13:28:37 -04:00
David S. Miller
fbb398a832 net/core/skbuff.c: Use frag list abstraction interfaces.
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-06-09 00:18:59 -07:00
Herbert Xu
5ff8dda303 net: Ensure partial checksum offset is inside the skb head
On Thu, Jun 04, 2009 at 09:06:00PM +1000, Herbert Xu wrote:
>
> tun: Optimise handling of bogus gso->hdr_len
>
> As all current versions of virtio_net generate a value for the
> header length that's too small, we should optimise this so that
> we don't copy it twice.  This can be done by ensuring that it is
> at least as large as the place where we'll write the checksum.
>
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

With this applied we can strengthen the partial checksum check:

In skb_partial_csum_set we check to see if the checksum offset
is within the packet.  However, we really should check that it
is within the skb head as that's the only bit we can modify
without copying.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-06-08 00:20:19 -07:00
Eric Dumazet
adf30907d6 net: skb->dst accessors
Define three accessors to get/set dst attached to a skb

struct dst_entry *skb_dst(const struct sk_buff *skb)

void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)

void skb_dst_drop(struct sk_buff *skb)
This one should replace occurrences of :
dst_release(skb->dst)
skb->dst = NULL;

Delete skb->dst field

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-06-03 02:51:04 -07:00
Herbert Xu
9aaa156cf9 gro: Store shinfo in local variable in skb_gro_receive
This patch stores the two shinfo pointers in local variables
because they're used over and over again in skb_gro_receive.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-05-27 03:26:05 -07:00
Herbert Xu
66e92fcf1d gro: Nasty optimisations for page frags in skb_gro_receive
This patch reverses the direction of the frags array copy in
skb_gro_receive in order simplify the loop conditional.  It
also avoids touching the first element of the original frags
array.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-05-27 03:26:04 -07:00
Herbert Xu
67147ba99a gro: Localise offset/headlen in skb_gro_offset
This patch stores the offset/headlen in local variables as they're
used repeatedly in skb_gro_offset.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-05-27 03:25:55 -07:00
Herbert Xu
42da6994ca gro: Open-code frags copy in skb_gro_receive
gcc does a poor job at generating code for the memcpy of the frags
array in skb_gro_receive, which is the primary purpose of that
function when merging frags.  In particular, it can't utilise the
alignment information of the source and destination.  This patch
open-codes the copy so we process words instead of bytes.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-05-27 03:25:54 -07:00
David S. Miller
c649c0e31d Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
	drivers/net/wireless/ath/ath5k/phy.c
	drivers/net/wireless/iwlwifi/iwl-agn.c
	drivers/net/wireless/iwlwifi/iwl3945-base.c
2009-05-25 01:42:21 -07:00
Herbert Xu
9bcb97cace skbuff: Copy csum instead of csum_start/csum_offset
Hi:

skbuff: Copy csum instead of csum_start/csum_offset

It's easier to copy the u32 csum instead of its two u16
constituents.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Cheers,
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-05-25 00:40:43 -07:00
Herbert Xu
82c49a352e skbuff: Move new code into __copy_skb_header
Hi:

skbuff: Move new __skb_clone code into __copy_skb_header

It seems that people just keep on adding stuff to __skb_clone
instead __copy_skb_header.  This is wrong as it means your brand-new
attributes won't always get copied as you intended.

This patch moves them to the right place, and adds a comment to
prevent this from happening again.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Thanks,
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-05-25 00:40:43 -07:00
Thomas Chenault
995b337952 net: fix skb_seq_read returning wrong offset/length for page frag data
When called with a consumed value that is less than skb_headlen(skb)
bytes into a page frag, skb_seq_read() incorrectly returns an
offset/length relative to skb->data. Ensure that data which should come
from a page frag does.

Signed-off-by: Thomas Chenault <thomas_chenault@dell.com>
Tested-by: Shyam Iyer <shyam_iyer@dell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-05-18 21:43:27 -07:00
Ingo Molnar
1079cac0f4 Merge commit 'v2.6.30-rc6' into tracing/core
Merge reason: we were on an -rc4 base, sync up to -rc6

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-18 10:15:35 +02:00
Ingo Molnar
44347d947f Merge branch 'linus' into tracing/core
Merge reason: tracing/core was on a .30-rc1 base and was missing out on
              on a handful of tracing fixes present in .30-rc5-almost.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-07 11:17:34 +02:00
Lennert Buytenhek
b805007545 net: update skb_recycle_check() for hardware timestamping changes
Commit ac45f602ee ("net: infrastructure
for hardware time stamping") added two skb initialization actions to
__alloc_skb(), which need to be added to skb_recycle_check() as well.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-05-06 16:49:18 -07:00
Jarek Poplawski
7a67e56fd3 net: Fix oops when splicing skbs from a frag_list.
Lennert Buytenhek wrote:
> Since 4fb6699481 ("net: Optimize memory
> usage when splicing from sockets.") I'm seeing this oops (e.g. in
> 2.6.30-rc3) when splicing from a TCP socket to /dev/null on a driver
> (mv643xx_eth) that uses LRO in the skb mode (lro_receive_skb) rather
> than the frag mode:

My patch incorrectly assumed skb->sk was always valid, but for
"frag_listed" skbs we can only use skb->sk of their parent.

Reported-by: Lennert Buytenhek <buytenh@wantstofly.org>
Debugged-by: Lennert Buytenhek <buytenh@wantstofly.org>
Tested-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-04-30 05:41:19 -07:00
Steven Rostedt
ad8d75fff8 tracing/events: move trace point headers into include/trace/events
Impact: clean up

Create a sub directory in include/trace called events to keep the
trace point headers in their own separate directory. Only headers that
declare trace points should be defined in this directory.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-04-14 22:05:43 -04:00
Herbert Xu
2f181855a0 gso: Fix support for linear packets
When GRO/frag_list support was added to GSO, I made an error
which broke the support for segmenting linear GSO packets (GSO
packets are normally non-linear in the payload).

These days most of these packets are constructed by the tun
driver, which prefers to allocate linear memory if possible.
This is fixed in the latest kernel, but for 2.6.29 and earlier
it is still the norm.

Therefore this bug causes failures with GSO when used with tun
in 2.6.29.

Reported-by: James Huang <jamesclhuang@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-03-28 23:39:18 -07:00
Neil Horman
ead2ceb0ec Network Drop Monitor: Adding kfree_skb_clean for non-drops and modifying end-of-line points for skbs
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>

 include/linux/skbuff.h |    4 +++-
 net/core/datagram.c    |    2 +-
 net/core/skbuff.c      |   22 ++++++++++++++++++++++
 net/ipv4/arp.c         |    2 +-
 net/ipv4/udp.c         |    2 +-
 net/packet/af_packet.c |    2 +-
 6 files changed, 29 insertions(+), 5 deletions(-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-03-13 12:09:28 -07:00
Wei Yongjun
f3fbbe0f6f core: remove some pointless conditionals before kfree_skb()
Remove some pointless conditionals before kfree_skb().

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-26 23:07:36 -08:00
David S. Miller
e70049b9e7 Merge branch 'master' of /home/davem/src/GIT/linux-2.6/ 2009-02-24 03:50:29 -08:00
David S. Miller
92a0acce18 net: Kill skb_truesize_check(), it only catches false-positives.
A long time ago we had bugs, primarily in TCP, where we would modify
skb->truesize (for TSO queue collapsing) in ways which would corrupt
the socket memory accounting.

skb_truesize_check() was added in order to try and catch this error
more systematically.

However this debugging check has morphed into a Frankenstein of sorts
and these days it does nothing other than catch false-positives.

Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-17 21:24:05 -08:00
Patrick Ohly
ac45f602ee net: infrastructure for hardware time stamping
The additional per-packet information (16 bytes for time stamps, 1
byte for flags) is stored for all packets in the skb_shared_info
struct. This implementation detail is hidden from users of that
information via skb_* accessor functions. A separate struct resp.
union is used for the additional information so that it can be
stored/copied easily outside of skb_shared_info.

Compared to previous implementations (reusing the tstamp field
depending on the context, optional additional structures) this
is the simplest solution. It does not extend sk_buff itself.

TX time stamping is implemented in software if the device driver
doesn't support hardware time stamping.

The new semantic for hardware/software time stamping around
ndo_start_xmit() is based on two assumptions about existing
network device drivers which don't support hardware time
stamping and know nothing about it:
 - they leave the new skb_shared_tx unmodified
 - the keep the connection to the originating socket in skb->sk
   alive, i.e., don't call skb_orphan()

Given that skb_shared_tx is new, the first assumption is safe.
The second is only true for some drivers. As a result, software
TX time stamping currently works with the bnx2 driver, but not
with the unmodified igb driver (the two drivers this patch series
was tested with).

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-15 22:43:34 -08:00
Jarek Poplawski
ce3dd39595 net: Fix page seeking for skb_splice_bits().
struct page walking should be done with proper accessor functions, not
directly.

With doubts from David S. Miller and Herbert Xu.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-12 16:51:43 -08:00
David S. Miller
b4ac530fc3 net: Move skbuff symbol exports after each symbol's definition.
net/core/skbuff.c is a hodge-podge of symbol export placement.
Some of the exports are right after the definition of the
symbol being exported, others are clumped together into a big
group at the end of the file.

Make things consistent.

Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-10 02:09:24 -08:00
Herbert Xu
56035022d8 gro: Fix frag_list merging on imprecisely split packets
The previous fix ad0f990444 (gro:
Fix handling of imprecisely split packets) only fixed the case
of frags merging, frag_list merging in the same circumstances
were still broken.

In particular, the packet headers end up in the data stream.

This patch fixes this plus another issue where an imprecisely
split packet header may be read incorrectly (this is mostly
harmless since it'll simply cause the packet to not match and
be rejected for GRO).

Thanks to Emil Tantilov and Jeff Kirsher for helping to track
this down.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-05 21:26:52 -08:00
Jarek Poplawski
4fb6699481 net: Optimize memory usage when splicing from sockets.
The recent fix of data corruption when splicing from sockets uses
memory very inefficiently allocating a new page to copy each chunk of
linear part of skb. This patch uses the same page until it's full
(almost) by caching the page in sk_sndmsg_page field.

With changes from David S. Miller <davem@davemloft.net>

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-01 00:41:42 -08:00
David S. Miller
05bee47377 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
	drivers/net/e1000/e1000_main.c
2009-01-30 14:31:07 -08:00
Herbert Xu
81705ad1b2 gro: Do not merge paged packets into frag_list
gro: Do not merge paged packets into frag_list

Bigger is not always better :)

It was easy to continue to merged packets into frag_list after the
page array is full.  However, this turns out to be worse than LRO
because frag_list is a much less efficient form of storage than the
page array.  So we're better off stopping the merge and starting
a new entry with an empty page array.

In future we can optimise this further by doing frag_list merging
but making sure that we continue to fill in the page array.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-29 16:33:04 -08:00
Herbert Xu
86911732d3 gro: Avoid copying headers of unmerged packets
Unfortunately simplicity isn't always the best.  The fraginfo
interface turned out to be suboptimal.  The problem was quite
obvious.  For every packet, we have to copy the headers from
the frags structure into skb->head, even though for 99% of the
packets this part is immediately thrown away after the merge.

LRO didn't have this problem because it directly read the headers
from the frags structure.

This patch attempts to address this by creating an interface
that allows GRO to access the headers in the first frag without
having to copy it.  Because all drivers that use frags place the
headers in the first frag this optimisation should be enough.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-29 16:33:03 -08:00
Shyam Iyer
71b3346d18 net: Fix OOPS in skb_seq_read().
It oopsd for me in skb_seq_read. addr2line said it was
linux-2.6/net/core/skbuff.c:2228, which is this line:


	while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {


I added some printks in there and it looks like we hit this:

        } else if (st->root_skb == st->cur_skb &&
                   skb_shinfo(st->root_skb)->frag_list) {
                 st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
                 st->frag_idx = 0;
                 goto next_skb;
        }



Actually I did some testing and added a few printks and found that the
st->cur_skb->data was 0 and hence the ptr used by iscsi_tcp was null.
This caused the kernel panic.

 	if (abs_offset < block_limit) {
-		*data = st->cur_skb->data + abs_offset;
+		*data = st->cur_skb->data + (abs_offset - st->stepped_offset);

I enabled the debug_tcp and with a few printks found that the code did
not go to the next_skb label and could find that the sequence being
followed was this -

It hit this if condition -

        if (st->cur_skb->next) {
                st->cur_skb = st->cur_skb->next;
                st->frag_idx = 0;
                goto next_skb;

And so, now the st pointer is shifted to the next skb whereas actually
it should have hit the second else if first since the data is in the
frag_list.

        else if (st->root_skb == st->cur_skb &&
                 skb_shinfo(st->root_skb)->frag_list) {
                st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
                goto next_skb;
        }

Reversing the two conditions the attached patch fixes the issue for me
on top of Herbert's patches. 

Signed-off-by: Shyam Iyer <shyam_iyer@dell.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-29 16:12:42 -08:00
Herbert Xu
95e3b24cfb net: Fix frag_list handling in skb_seq_read
The frag_list handling was broken in skb_seq_read:

1) We didn't add the stepped offset when looking at the head
are of fragments other than the first.

2) We didn't take the stepped offset away when setting the data
pointer in the head area.

3) The frag index wasn't reset.

This patch fixes both issues.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-29 16:07:52 -08:00
Herbert Xu
37fe4732b9 gro: Fix merging of paged packets
The previous fix to paged packets broke the merging because it
reset the skb->len before we added it to the merged packet.  This
wasn't detected because it simply resulted in the truncation of
the packet while the missing bit is subsequently retransmitted.

The fix is to store skb->len before we clobber it.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-20 14:44:03 -08:00
Jarek Poplawski
8b9d372897 net: Fix data corruption when splicing from sockets.
The trick in socket splicing where we try to convert the skb->data
into a page based reference using virt_to_page() does not work so
well.

The idea is to pass the virt_to_page() reference via the pipe
buffer, and refcount the buffer using a SKB reference.

But if we are splicing from a socket to a socket (via sendpage)
this doesn't work.

The from side processing will grab the page (and SKB) references.
The sendpage() calls will grab page references only, return, and
then the from side processing completes and drops the SKB ref.

The page based reference to skb->data is not enough to keep the
kmalloc() buffer backing it from being reused.  Yet, that is
all that the socket send side has at this point.

This leads to data corruption if the skb->data buffer is reused
by SLAB before the send side socket actually gets the TX packet
out to the device.

The fix employed here is to simply allocate a page and copy the
skb->data bytes into that page.

This will hurt performance, but there is no clear way to fix this
properly without a copy at the present time, and it is important
to get rid of the data corruption.

With fixes from Herbert Xu.

Tested-by: Willy Tarreau <w@1wt.eu>
Foreseen-by: Changli Gao <xiaosuo@gmail.com>
Diagnosed-by: Willy Tarreau <w@1wt.eu>
Reported-by: Willy Tarreau <w@1wt.eu>
Fixed-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-19 17:03:56 -08:00
Herbert Xu
f557206800 gro: Fix page ref count for skbs freed normally
When an skb with page frags is merged into an existing one, we
cannibalise its reference count.  This is OK when the skb is
reused because we set nr_frags to zero in that case.  However,
for the case where the skb is freed through kfree_skb, we didn't
clear nr_frags which causes the page to be freed prematurely.

This is fixed by moving the skb resetting into skb_gro_receive.

Reported-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-14 20:40:03 -08:00
Herbert Xu
5d38a079ce gro: Add page frag support
This patch allows GRO to merge page frags (skb_shinfo(skb)->frags)
in one skb, rather than using the less efficient frag_list.

It also adds a new interface, napi_gro_frags to allow drivers
to inject page frags directly into the stack without allocating
an skb.  This is intended to be the GRO equivalent for LRO's
lro_receive_frags interface.

The existing GSO interface can already handle page frags with
or without an appended frag_list so nothing needs to be changed
there.

The merging itself is rather simple.  We store any new frag entries
after the last existing entry, without checking whether the first
new entry can be merged with the last existing entry.  Making this
check would actually be easy but since no existing driver can
produce contiguous frags anyway it would just be mental masturbation.

If the total number of entries would exceed the capacity of a
single skb, we simply resort to using frag_list as we do now.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-04 16:13:40 -08:00