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  1. 04 11月, 2011 1 次提交
    • T
      net: Add back alignment for size for __alloc_skb · bc417e30
      由 Tony Lindgren 提交于 
      Commit 87fb4b7b (net: more
accurate skb truesize) changed the alignment of size. This
can cause problems at least on some machines with NFS root:

Unhandled fault: alignment exception (0x801) at 0xc183a43a
Internal error: : 801 [#1] PREEMPT
Modules linked in:
CPU: 0    Not tainted  (3.1.0-08784-g5eeee4a #733)
pc : [<c02fbba0>]    lr : [<c02fbb9c>]    psr: 60000013
sp : c180fef8  ip : 00000000  fp : c181f580
r10: 00000000  r9 : c044b28c  r8 : 00000001
r7 : c183a3a0  r6 : c1835be0  r5 : c183a412  r4 : 000001f2
r3 : 00000000  r2 : 00000000  r1 : ffffffe6  r0 : c183a43a
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
Control: 0005317f  Table: 10004000  DAC: 00000017
Process swapper (pid: 1, stack limit = 0xc180e270)
Stack: (0xc180fef8 to 0xc1810000)
fee0:                                                       00000024 00000000
ff00: 00000000 c183b9c0 c183b8e0 c044b28c c0507ccc c019dfc4 c180ff2c c0503cf8
ff20: c180ff4c c180ff4c 00000000 c1835420 c182c740 c18349c0 c05233c0 00000000
ff40: 00000000 c00e6bb8 c180e000 00000000 c04dd82c c0507e7c c050cc18 c183b9c0
ff60: c05233c0 00000000 00000000 c01f34f4 c0430d70 c019d364 c04dd898 c04dd898
ff80: c04dd82c c0507e7c c180e000 00000000 c04c584c c01f4918 c04dd898 c04dd82c
ffa0: c04ddd28 c180e000 00000000 c0008758 c181fa60 3231d82c 00000037 00000000
ffc0: 00000000 c04dd898 c04dd82c c04ddd28 00000013 00000000 00000000 00000000
ffe0: 00000000 c04b2224 00000000 c04b21a0 c001056c c001056c 00000000 00000000
Function entered at [<c02fbba0>] from [<c019dfc4>]
Function entered at [<c019dfc4>] from [<c01f34f4>]
Function entered at [<c01f34f4>] from [<c01f4918>]
Function entered at [<c01f4918>] from [<c0008758>]
Function entered at [<c0008758>] from [<c04b2224>]
Function entered at [<c04b2224>] from [<c001056c>]
Code: e1a00005 e3a01028 ebfa7cb0 e35a0000 (e5858028)

Here PC is at __alloc_skb and &shinfo->dataref is unaligned because
skb->end can be unaligned without this patch.

As explained by Eric Dumazet <eric.dumazet@gmail.com>, this happens
only with SLOB, and not with SLAB or SLUB:

* Eric Dumazet <eric.dumazet@gmail.com> [111102 15:56]:
>
> Your patch is absolutely needed, I completely forgot about SLOB :(
>
> since, kmalloc(386) on SLOB gives exactly ksize=386 bytes, not nearest
> power of two.
>
> [   60.305763] malloc(size=385)->ffff880112c11e38 ksize=386 -> nsize=2
> [   60.305921] malloc(size=385)->ffff88007c92ce28 ksize=386 -> nsize=2
> [   60.306898] malloc(size=656)->ffff88007c44ad28 ksize=656 -> nsize=272
> [   60.325385] malloc(size=656)->ffff88007c575868 ksize=656 -> nsize=272
> [   60.325531] malloc(size=656)->ffff88011c777230 ksize=656 -> nsize=272
> [   60.325701] malloc(size=656)->ffff880114011008 ksize=656 -> nsize=272
> [   60.346716] malloc(size=385)->ffff880114142008 ksize=386 -> nsize=2
> [   60.346900] malloc(size=385)->ffff88011c777690 ksize=386 -> nsize=2
Signed-off-by: NTony Lindgren <tony@atomide.com>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      bc417e30
  3. 21 10月, 2011 1 次提交
  5. 20 10月, 2011 1 次提交
  7. 19 10月, 2011 1 次提交
  9. 14 10月, 2011 1 次提交
    • E
      net: more accurate skb truesize · 87fb4b7b
      由 Eric Dumazet 提交于 
      skb truesize currently accounts for sk_buff struct and part of skb head.
kmalloc() roundings are also ignored.

Considering that skb_shared_info is larger than sk_buff, its time to
take it into account for better memory accounting.

This patch introduces SKB_TRUESIZE(X) macro to centralize various
assumptions into a single place.

At skb alloc phase, we put skb_shared_info struct at the exact end of
skb head, to allow a better use of memory (lowering number of
reallocations), since kmalloc() gives us power-of-two memory blocks.

Unless SLUB/SLUB debug is active, both skb->head and skb_shared_info are
aligned to cache lines, as before.

Note: This patch might trigger performance regressions because of
misconfigured protocol stacks, hitting per socket or global memory
limits that were previously not reached. But its a necessary step for a
more accurate memory accounting.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Andi Kleen <ak@linux.intel.com>
CC: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      87fb4b7b
  11. 16 9月, 2011 1 次提交
    • M
      net: copy userspace buffers on device forwarding · 48c83012
      由 Michael S. Tsirkin 提交于 
      dev_forward_skb loops an skb back into host networking
stack which might hang on the memory indefinitely.
In particular, this can happen in macvtap in bridged mode.
Copy the userspace fragments to avoid blocking the
sender in that case.

As this patch makes skb_copy_ubufs extern now,
I also added some documentation and made it clear
the SKBTX_DEV_ZEROCOPY flag automatically instead
of doing it in all callers. This can be made into a separate
patch if people feel it's worth it.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      48c83012
  13. 25 8月, 2011 1 次提交
  15. 21 8月, 2011 1 次提交
  17. 18 8月, 2011 1 次提交
  19. 02 8月, 2011 1 次提交
  21. 22 7月, 2011 1 次提交
  23. 09 7月, 2011 1 次提交
  25. 07 7月, 2011 1 次提交
    • S
      skbuff: skb supports zero-copy buffers · a6686f2f
      由 Shirley Ma 提交于 
      This patch adds userspace buffers support in skb shared info. A new
struct skb_ubuf_info is needed to maintain the userspace buffers
argument and index, a callback is used to notify userspace to release
the buffers once lower device has done DMA (Last reference to that skb
has gone).

If there is any userspace apps to reference these userspace buffers,
then these userspaces buffers will be copied into kernel. This way we
can prevent userspace apps from holding these userspace buffers too long.

Use destructor_arg to point to the userspace buffer info; a new tx flags
SKBTX_DEV_ZEROCOPY is added for zero-copy buffer check.
Signed-off-by: NShirley Ma <xma@...ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      a6686f2f
  27. 21 5月, 2011 1 次提交
    • L
      sanitize <linux/prefetch.h> usage · 268bb0ce
      由 Linus Torvalds 提交于 
      Commit e66eed65 ("list: remove prefetching from regular list
iterators") removed the include of prefetch.h from list.h, which
uncovered several cases that had apparently relied on that rather
obscure header file dependency.

So this fixes things up a bit, using

   grep -L linux/prefetch.h $(git grep -l '[^a-z_]prefetchw*(' -- '*.[ch]')
   grep -L 'prefetchw*(' $(git grep -l 'linux/prefetch.h' -- '*.[ch]')

to guide us in finding files that either need <linux/prefetch.h>
inclusion, or have it despite not needing it.

There are more of them around (mostly network drivers), but this gets
many core ones.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      268bb0ce
  29. 18 5月, 2011 1 次提交
    • E
      net: add skb_dst_force() in sock_queue_err_skb() · abb57ea4
      由 Eric Dumazet 提交于 
      Commit 7fee226a (add a noref bit on skb dst) forgot to use
skb_dst_force() on packets queued in sk_error_queue

This triggers following warning, for applications using IP_CMSG_PKTINFO
receiving one error status


------------[ cut here ]------------
WARNING: at include/linux/skbuff.h:457 ip_cmsg_recv_pktinfo+0xa6/0xb0()
Hardware name: 2669UYD
Modules linked in: isofs vboxnetadp vboxnetflt nfsd ebtable_nat ebtables
lib80211_crypt_ccmp uinput xcbc hdaps tp_smapi thinkpad_ec radeonfb fb_ddc
radeon ttm drm_kms_helper drm ipw2200 intel_agp intel_gtt libipw i2c_algo_bit
i2c_i801 agpgart rng_core cfbfillrect cfbcopyarea cfbimgblt video raid10 raid1
raid0 linear md_mod vboxdrv
Pid: 4697, comm: miredo Not tainted 2.6.39-rc6-00569-g5895198c-dirty #22
Call Trace:
 [<c17746b6>] ? printk+0x1d/0x1f
 [<c1058302>] warn_slowpath_common+0x72/0xa0
 [<c15bbca6>] ? ip_cmsg_recv_pktinfo+0xa6/0xb0
 [<c15bbca6>] ? ip_cmsg_recv_pktinfo+0xa6/0xb0
 [<c1058350>] warn_slowpath_null+0x20/0x30
 [<c15bbca6>] ip_cmsg_recv_pktinfo+0xa6/0xb0
 [<c15bbdd7>] ip_cmsg_recv+0x127/0x260
 [<c154f82d>] ? skb_dequeue+0x4d/0x70
 [<c1555523>] ? skb_copy_datagram_iovec+0x53/0x300
 [<c178e834>] ? sub_preempt_count+0x24/0x50
 [<c15bdd2d>] ip_recv_error+0x23d/0x270
 [<c15de554>] udp_recvmsg+0x264/0x2b0
 [<c15ea659>] inet_recvmsg+0xd9/0x130
 [<c1547752>] sock_recvmsg+0xf2/0x120
 [<c11179cb>] ? might_fault+0x4b/0xa0
 [<c15546bc>] ? verify_iovec+0x4c/0xc0
 [<c1547660>] ? sock_recvmsg_nosec+0x100/0x100
 [<c1548294>] __sys_recvmsg+0x114/0x1e0
 [<c1093895>] ? __lock_acquire+0x365/0x780
 [<c1148b66>] ? fget_light+0xa6/0x3e0
 [<c1148b7f>] ? fget_light+0xbf/0x3e0
 [<c1148aee>] ? fget_light+0x2e/0x3e0
 [<c1549f29>] sys_recvmsg+0x39/0x60

Close bug https://bugzilla.kernel.org/show_bug.cgi?id=34622Reported-by: NWitold Baryluk <baryluk@smp.if.uj.edu.pl>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      abb57ea4
  31. 31 3月, 2011 1 次提交
  33. 17 3月, 2011 1 次提交
  35. 02 3月, 2011 1 次提交
  37. 28 1月, 2011 1 次提交
  39. 25 1月, 2011 2 次提交
    • M
      net: change netdev->features to u32 · 04ed3e74
      由 Michał Mirosław 提交于 
      Quoting Ben Hutchings: we presumably won't be defining features that
can only be enabled on 64-bit architectures.

Occurences found by `grep -r` on net/, drivers/net, include/

[ Move features and vlan_features next to each other in
  struct netdev, as per Eric Dumazet's suggestion -DaveM ]
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      04ed3e74
    • M
      GRO: fix merging a paged skb after non-paged skbs · d1dc7abf
      由 Michal Schmidt 提交于 
      Suppose that several linear skbs of the same flow were received by GRO. They
were thus merged into one skb with a frag_list. Then a new skb of the same flow
arrives, but it is a paged skb with data starting in its frags[].

Before adding the skb to the frag_list skb_gro_receive() will of course adjust
the skb to throw away the headers. It correctly modifies the page_offset and
size of the frag, but it leaves incorrect information in the skb:
 ->data_len is not decreased at all.
 ->len is decreased only by headlen, as if no change were done to the frag.
Later in a receiving process this causes skb_copy_datagram_iovec() to return
-EFAULT and this is seen in userspace as the result of the recv() syscall.

In practice the bug can be reproduced with the sfc driver. By default the
driver uses an adaptive scheme when it switches between using
napi_gro_receive() (with skbs) and napi_gro_frags() (with pages). The bug is
reproduced when under rx load with enough successful GRO merging the driver
decides to switch from the former to the latter.

Manual control is also possible, so reproducing this is easy with netcat:
 - on machine1 (with sfc): nc -l 12345 > /dev/null
 - on machine2: nc machine1 12345 < /dev/zero
 - on machine1:
   echo 1 > /sys/module/sfc/parameters/rx_alloc_method  # use skbs
   echo 2 > /sys/module/sfc/parameters/rx_alloc_method  # use pages
 - See that nc has quit suddenly.

[v2: Modified by Eric Dumazet to avoid advancing skb->data past the end
     and to use a temporary variable.]
Signed-off-by: NMichal Schmidt <mschmidt@redhat.com>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      d1dc7abf
  41. 13 1月, 2011 1 次提交
  43. 17 12月, 2010 1 次提交
  45. 16 12月, 2010 1 次提交
  47. 04 12月, 2010 1 次提交
  49. 17 10月, 2010 1 次提交
    • E
      net: allocate skbs on local node · 564824b0
      由 Eric Dumazet 提交于 
      commit b30973f8 (node-aware skb allocation) spread a wrong habit of
allocating net drivers skbs on a given memory node : The one closest to
the NIC hardware. This is wrong because as soon as we try to scale
network stack, we need to use many cpus to handle traffic and hit
slub/slab management on cross-node allocations/frees when these cpus
have to alloc/free skbs bound to a central node.

skb allocated in RX path are ephemeral, they have a very short
lifetime : Extra cost to maintain NUMA affinity is too expensive. What
appeared as a nice idea four years ago is in fact a bad one.

In 2010, NIC hardwares are multiqueue, or we use RPS to spread the load,
and two 10Gb NIC might deliver more than 28 million packets per second,
needing all the available cpus.

Cost of cross-node handling in network and vm stacks outperforms the
small benefit hardware had when doing its DMA transfert in its 'local'
memory node at RX time. Even trying to differentiate the two allocations
done for one skb (the sk_buff on local node, the data part on NIC
hardware node) is not enough to bring good performance.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Acked-by: NTom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      564824b0
  51. 09 9月, 2010 1 次提交
  53. 07 9月, 2010 2 次提交
    • K
      skb: Add tracepoints to freeing skb · 07dc22e7
      由 Koki Sanagi 提交于 
      This patch adds tracepoint to consume_skb and add trace_kfree_skb
before __kfree_skb in skb_free_datagram_locked and net_tx_action.
Combinating with tracepoint on dev_hard_start_xmit, we can check
how long it takes to free transmitted packets. And using it, we can
calculate how many packets driver had at that time. It is useful when
a drop of transmitted packet is a problem.

            sshd-6828  [000] 112689.258154: consume_skb: skbaddr=f2d99bb8
Signed-off-by: NKoki Sanagi <sanagi.koki@jp.fujitsu.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Kaneshige Kenji <kaneshige.kenji@jp.fujitsu.com>
Cc: Izumo Taku <izumi.taku@jp.fujitsu.com>
Cc: Kosaki Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Scott Mcmillan <scott.a.mcmillan@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
LKML-Reference: <4C724364.50903@jp.fujitsu.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      07dc22e7
    • E
      net: pskb_expand_head() optimization · 1fd63041
      由 Eric Dumazet 提交于 
      pskb_expand_head() blindly takes references on fragments before calling
skb_release_data(), potentially releasing these references.

We can add a fast path, avoiding these atomic operations, if we own the
last reference on skb->head.

Based on a previous patch from David
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1fd63041
  55. 04 9月, 2010 1 次提交
  57. 02 9月, 2010 2 次提交
    • E
      gro: fix different skb headrooms · 3d3be433
      由 Eric Dumazet 提交于 
      Packets entering GRO might have different headrooms, even for a given
flow (because of implementation details in drivers, like copybreak).
We cant force drivers to deliver packets with a fixed headroom.

1) fix skb_segment()

skb_segment() makes the false assumption headrooms of fragments are same
than the head. When CHECKSUM_PARTIAL is used, this can give csum_start
errors, and crash later in skb_copy_and_csum_dev()

2) allocate a minimal skb for head of frag_list

skb_gro_receive() uses netdev_alloc_skb(headroom + skb_gro_offset(p)) to
allocate a fresh skb. This adds NET_SKB_PAD to a padding already
provided by netdevice, depending on various things, like copybreak.

Use alloc_skb() to allocate an exact padding, to reduce cache line
needs:
NET_SKB_PAD + NET_IP_ALIGN

bugzilla : https://bugzilla.kernel.org/show_bug.cgi?id=16626

Many thanks to Plamen Petrov, testing many debugging patches !
With help of Jarek Poplawski.
Reported-by: NPlamen Petrov <pvp-lsts@fs.uni-ruse.bg>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      3d3be433
    • E
      net: skbuff.c cleanup · 6602cebb
      由 Eric Dumazet 提交于 
      (skb->data - skb->head) can be changed by skb_headroom(skb)

Remove some uses of NET_SKBUFF_DATA_USES_OFFSET, using
(skb_end_pointer(skb) - skb->head) or
(skb_tail_pointer(skb) - skb->head) : compiler does the right thing,
and this is more readable for us ;)

(struct skb_shared_info *) casts in pskb_expand_head() to help memcpy()
to use aligned moves.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      6602cebb
  59. 23 8月, 2010 1 次提交
  61. 19 8月, 2010 1 次提交
  63. 25 7月, 2010 1 次提交
  65. 23 7月, 2010 2 次提交
  67. 13 7月, 2010 1 次提交
  69. 14 6月, 2010 2 次提交