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  1. 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
  3. 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
  5. 25 8月, 2011 1 次提交
  7. 23 8月, 2011 1 次提交
  9. 19 8月, 2011 1 次提交
  11. 18 8月, 2011 1 次提交
  13. 27 7月, 2011 1 次提交
  15. 12 7月, 2011 1 次提交
  17. 10 7月, 2011 1 次提交
  19. 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
  21. 20 6月, 2011 1 次提交
  23. 12 6月, 2011 1 次提交
    • J
      vlan: Fix the ingress VLAN_FLAG_REORDER_HDR check · 0b5c9db1
      由 Jiri Pirko 提交于 
      Testing of VLAN_FLAG_REORDER_HDR does not belong in vlan_untag
but rather in vlan_do_receive.  Otherwise the vlan header
will not be properly put on the packet in the case of
vlan header accelleration.

As we remove the check from vlan_check_reorder_header
rename it vlan_reorder_header to keep the naming clean.

Fix up the skb->pkt_type early so we don't look at the packet
after adding the vlan tag, which guarantees we don't goof
and look at the wrong field.

Use a simple if statement instead of a complicated switch
statement to decided that we need to increment rx_stats
for a multicast packet.

Hopefully at somepoint we will just declare the case where
VLAN_FLAG_REORDER_HDR is cleared as unsupported and remove
the code.  Until then this keeps it working correctly.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Acked-by: NChangli Gao <xiaosuo@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      0b5c9db1
  25. 23 5月, 2011 5 次提交
  27. 28 4月, 2011 1 次提交
    • E
      net: filter: Just In Time compiler for x86-64 · 0a14842f
      由 Eric Dumazet 提交于 
      In order to speedup packet filtering, here is an implementation of a
JIT compiler for x86_64

It is disabled by default, and must be enabled by the admin.

echo 1 >/proc/sys/net/core/bpf_jit_enable

It uses module_alloc() and module_free() to get memory in the 2GB text
kernel range since we call helpers functions from the generated code.

EAX : BPF A accumulator
EBX : BPF X accumulator
RDI : pointer to skb   (first argument given to JIT function)
RBP : frame pointer (even if CONFIG_FRAME_POINTER=n)
r9d : skb->len - skb->data_len (headlen)
r8  : skb->data

To get a trace of generated code, use :

echo 2 >/proc/sys/net/core/bpf_jit_enable

Example of generated code :

# tcpdump -p -n -s 0 -i eth1 host 192.168.20.0/24

flen=18 proglen=147 pass=3 image=ffffffffa00b5000
JIT code: ffffffffa00b5000: 55 48 89 e5 48 83 ec 60 48 89 5d f8 44 8b 4f 60
JIT code: ffffffffa00b5010: 44 2b 4f 64 4c 8b 87 b8 00 00 00 be 0c 00 00 00
JIT code: ffffffffa00b5020: e8 24 7b f7 e0 3d 00 08 00 00 75 28 be 1a 00 00
JIT code: ffffffffa00b5030: 00 e8 fe 7a f7 e0 24 00 3d 00 14 a8 c0 74 49 be
JIT code: ffffffffa00b5040: 1e 00 00 00 e8 eb 7a f7 e0 24 00 3d 00 14 a8 c0
JIT code: ffffffffa00b5050: 74 36 eb 3b 3d 06 08 00 00 74 07 3d 35 80 00 00
JIT code: ffffffffa00b5060: 75 2d be 1c 00 00 00 e8 c8 7a f7 e0 24 00 3d 00
JIT code: ffffffffa00b5070: 14 a8 c0 74 13 be 26 00 00 00 e8 b5 7a f7 e0 24
JIT code: ffffffffa00b5080: 00 3d 00 14 a8 c0 75 07 b8 ff ff 00 00 eb 02 31
JIT code: ffffffffa00b5090: c0 c9 c3

BPF program is 144 bytes long, so native program is almost same size ;)

(000) ldh      [12]
(001) jeq      #0x800           jt 2    jf 8
(002) ld       [26]
(003) and      #0xffffff00
(004) jeq      #0xc0a81400      jt 16   jf 5
(005) ld       [30]
(006) and      #0xffffff00
(007) jeq      #0xc0a81400      jt 16   jf 17
(008) jeq      #0x806           jt 10   jf 9
(009) jeq      #0x8035          jt 10   jf 17
(010) ld       [28]
(011) and      #0xffffff00
(012) jeq      #0xc0a81400      jt 16   jf 13
(013) ld       [38]
(014) and      #0xffffff00
(015) jeq      #0xc0a81400      jt 16   jf 17
(016) ret      #65535
(017) ret      #0
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Cc: Hagen Paul Pfeifer <hagen@jauu.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      0a14842f
  29. 31 3月, 2011 1 次提交
  31. 30 3月, 2011 1 次提交
    • D
      net: Fix warnings caused by MAX_SKB_FRAGS change. · eec00954
      由 David S. Miller 提交于 
      After commit a715dea3 ("net: Always
allocate at least 16 skb frags regardless of page size"), the value
of MAX_SKB_FRAGS can now take on either an "unsigned long" or an
"int" value.

This causes warnings like:

net/packet/af_packet.c: In function ‘tpacket_fill_skb’:
net/packet/af_packet.c:948: warning: format ‘%lu’ expects type ‘long unsigned int’, but argument 2 has type ‘int’

Fix by forcing the constant to be unsigned long, otherwise we have
a situation where the type of a system wide constant is variable.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      eec00954
  33. 29 3月, 2011 1 次提交
  35. 17 3月, 2011 1 次提交
  37. 25 1月, 2011 1 次提交
  39. 21 1月, 2011 1 次提交
  41. 13 1月, 2011 1 次提交
  43. 17 12月, 2010 2 次提交
  45. 16 12月, 2010 1 次提交
  47. 25 11月, 2010 1 次提交
    • T
      xps: Improvements in TX queue selection · 3853b584
      由 Tom Herbert 提交于 
      In dev_pick_tx, don't do work in calculating queue
index or setting
the index in the sock unless the device has more than one queue.  This
allows the sock to be set only with a queue index of a multi-queue
device which is desirable if device are stacked like in a tunnel.

We also allow the mapping of a socket to queue to be changed.  To
maintain in order packet transmission a flag (ooo_okay) has been
added to the sk_buff structure.  If a transport layer sets this flag
on a packet, the transmit queue can be changed for the socket.
Presumably, the transport would set this if there was no possbility
of creating OOO packets (for instance, there are no packets in flight
for the socket).  This patch includes the modification in TCP output
for setting this flag.
Signed-off-by: NTom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      3853b584
  49. 20 10月, 2010 1 次提交
    • E
      net: avoid RCU for NOCACHE dst · 27b75c95
      由 Eric Dumazet 提交于 
      There is no point using RCU for dst we allocate for a very short time
(used once).

Change dst_release() to take DST_NOCACHE into account, but also change
skb_dst_set_noref() to force a refcount increment for such dst.

This is a _huge_ gain, because we dont waste memory to store xx thousand
of dsts. Instead of queueing them to RCU, we can free them instantly.

CPU caches can stay hot, re-using same memory blocks to hold temporary
dsts.

Note : remove unneeded smp_mb__before_atomic_dec(); in dst_release(),
since atomic_dec_return() implies a full memory barrier.

Stress test, 160.000.000 udp frames sent, IP route cache disabled
(DDOS).

Before:

real    0m38.091s
user    0m13.189s
sys     7m53.018s

After:

real	0m29.946s
user	0m12.157s
sys	7m40.605s

For reference, if IP route cache was enabled :

real	0m32.030s
user	0m10.521s
sys	8m15.243s
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      27b75c95
  51. 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
  53. 27 9月, 2010 1 次提交
  55. 24 9月, 2010 1 次提交
  57. 03 9月, 2010 1 次提交
  59. 23 8月, 2010 1 次提交
  61. 19 8月, 2010 1 次提交
  63. 17 8月, 2010 1 次提交
    • K
      core: Factor out flow calculation from get_rps_cpu · bfb564e7
      由 Krishna Kumar 提交于 
      Factor out flow calculation code from get_rps_cpu, since other
functions can use the same code.

Revisions:

v2 (Ben): Separate flow calcuation out and use in select queue.
v3 (Arnd): Don't re-implement MIN.
v4 (Changli): skb->data points to ethernet header in macvtap, and
	make a fast path. Tested macvtap with this patch.
v5 (Changli):
	- Cache skb->rxhash in skb_get_rxhash
	- macvtap may not have pow(2) queues, so change code for
	  queue selection.
    (Arnd):
	- Use first available queue if all fails.
Signed-off-by: NKrishna Kumar <krkumar2@in.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      bfb564e7
  65. 05 8月, 2010 1 次提交
  67. 03 8月, 2010 1 次提交
  69. 25 7月, 2010 1 次提交