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  1. 05 9月, 2013 1 次提交
    • T
      ipv6: Don't depend on per socket memory for neighbour discovery messages · 25a6e6b8
      由 Thomas Graf 提交于 
      Allocating skbs when sending out neighbour discovery messages
currently uses sock_alloc_send_skb() based on a per net namespace
socket and thus share a socket wmem buffer space.

If a netdevice is temporarily unable to transmit due to carrier
loss or for other reasons, the queued up ndisc messages will cosnume
all of the wmem space and will thus prevent from any more skbs to
be allocated even for netdevices that are able to transmit packets.

The number of neighbour discovery messages sent is very limited,
use of alloc_skb() bypasses the socket wmem buffer size enforcement
while the manual call to skb_set_owner_w() maintains the socket
reference needed for the IPv6 output path.

This patch has orginally been posted by Eric Dumazet in a modified
form.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Fabio Estevam <festevam@gmail.com>
Tested-by: NFabio Estevam <fabio.estevam@freescale.com>
Tested-by: NStephen Warren <swarren@nvidia.com>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      25a6e6b8
  3. 31 8月, 2013 1 次提交
  5. 30 8月, 2013 1 次提交
  7. 23 8月, 2013 1 次提交
  9. 02 8月, 2013 1 次提交
    • M
      ipv6: prevent fib6_run_gc() contention · 2ac3ac8f
      由 Michal Kubeček 提交于 
      On a high-traffic router with many processors and many IPv6 dst
entries, soft lockup in fib6_run_gc() can occur when number of
entries reaches gc_thresh.

This happens because fib6_run_gc() uses fib6_gc_lock to allow
only one thread to run the garbage collector but ip6_dst_gc()
doesn't update net->ipv6.ip6_rt_last_gc until fib6_run_gc()
returns. On a system with many entries, this can take some time
so that in the meantime, other threads pass the tests in
ip6_dst_gc() (ip6_rt_last_gc is still not updated) and wait for
the lock. They then have to run the garbage collector one after
another which blocks them for quite long.

Resolve this by replacing special value ~0UL of expire parameter
to fib6_run_gc() by explicit "force" parameter to choose between
spin_lock_bh() and spin_trylock_bh() and call fib6_run_gc() with
force=false if gc_thresh is reached but not max_size.
Signed-off-by: NMichal Kubecek <mkubecek@suse.cz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      2ac3ac8f
  11. 17 7月, 2013 1 次提交
  13. 18 6月, 2013 1 次提交
  15. 29 5月, 2013 2 次提交
  17. 09 3月, 2013 1 次提交
  19. 22 1月, 2013 19 次提交
  21. 21 1月, 2013 2 次提交
  23. 19 1月, 2013 2 次提交
  25. 07 1月, 2013 1 次提交
  27. 05 1月, 2013 1 次提交
    • Y
      ndisc: Remove unused space at tail of skb for ndisc messages. (TAKE 3) · b7dc8c39
      由 YOSHIFUJI Hideaki / 吉藤英明 提交于 
      Currently, the size of skb allocated for NDISC is MAX_HEADER +
LL_RESERVED_SPACE(dev) + packet length + dev->needed_tailroom,
but only LL_RESERVED_SPACE(dev) bytes is "reserved" for headers.
As a result, the skb looks like this (after construction of the
message):

head       data                   tail                       end
+--------------------------------------------------------------+
+           |                      |          |                |
+--------------------------------------------------------------+
|<-hlen---->|<---ipv6 packet------>|<--tlen-->|<--MAX_HEADER-->|
    =LL_                               = dev
     RESERVED_                           ->needed_
     SPACE(dev)                            tailroom

As the name implies, "MAX_HEADER" is used for headers, and should
be "reserved" in prior to packet construction.  Or, if some space
is really required at the tail of ther skb, it should be
explicitly documented.

We have several option after construction of NDISC message:

Option 1:

head       data                   tail       end
+---------------------------------------------+
+           |                      |          |
+---------------------------------------------+
|<-hlen---->|<---ipv6 packet------>|<--tlen-->|
   =LL_                                = dev
    RESERVED_                           ->needed_
    SPACE(dev)                            tailroom

Option 2:

head            data                   tail       end
+--------------------------------------------------+
+                |                      |          |
+--------------------------------------------------+
|<--MAX_HEADER-->|<---ipv6 packet------>|<--tlen-->|
                                            = dev
                                             ->needed_
                                               tailroom

Option 3:

head                        data                   tail       end
+--------------------------------------------------------------+
+                |           |                      |          |
+--------------------------------------------------------------+
|<--MAX_HEADER-->|<-hlen---->|<---ipv6 packet------>|<--tlen-->|
                    =LL_                                = dev
                     RESERVED_                          ->needed_
                     SPACE(dev)                           tailroom

Our tunnel drivers try expanding headroom and the space for tunnel
encapsulation was not a mandatory space -- so we are not seeing
bugs here --, but just for optimization for performance critial
situations.

Since NDISC messages are not performance critical unlike TCP,
and as we know outgoing device, LL_RESERVED_SPACE(dev) should be
just enough for the device in most (if not all) cases:
  LL_RESERVED_SPACE(dev) <= LL_MAX_HEADER <= MAX_HEADER
Note that LL_RESERVED_SPACE(dev) is also enough for NDISC over
SIT (e.g., ISATAP).

So, I think Option 1 is just fine here.
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      b7dc8c39
  29. 15 12月, 2012 1 次提交
  31. 14 12月, 2012 1 次提交
  33. 13 12月, 2012 1 次提交
  35. 02 12月, 2012 1 次提交
  37. 14 11月, 2012 1 次提交