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  1. 23 Jul, 2012 7 commits
    • Eric Dumazet's avatar
      tcp: dont drop MTU reduction indications · 563d34d0
      Eric Dumazet authored 
      ICMP messages generated in output path if frame length is bigger than
mtu are actually lost because socket is owned by user (doing the xmit)

One example is the ipgre_tunnel_xmit() calling
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));

We had a similar case fixed in commit a34a101e (ipv6: disable GSO on
sockets hitting dst_allfrag).

Problem of such fix is that it relied on retransmit timers, so short tcp
sessions paid a too big latency increase price.

This patch uses the tcp_release_cb() infrastructure so that MTU
reduction messages (ICMP messages) are not lost, and no extra delay
is added in TCP transmits.
Reported-by: default avatarMaciej Żenczykowski <maze@google.com>
Diagnosed-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Nandita Dukkipati <nanditad@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Tore Anderson <tore@fud.no>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      563d34d0
    • Yuval Mintz's avatar
      bnx2x: Add new 57840 device IDs · c3def943
      Yuval Mintz authored 
      The 57840 boards come in two flavours: 2 x 20G and 4 x 10G.
To better differentiate between the two flavours, a separate device ID
was assigned to each.
The silicon default value is still the currently supported 57840 device ID
(0x168d), and since a user can damage the nvram (e.g., 'ethtool -E')
the driver will still support this device ID to allow the user to amend the
nvram back into a supported configuration.

Notice this patch contains lines longer than 80 characters (strings).
Signed-off-by: default avatarYuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: default avatarEilon Greenstein <eilong@broadcom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c3def943
    • Julian Anastasov's avatar
      tcp: avoid oops in tcp_metrics and reset tcpm_stamp · 9a0a9502
      Julian Anastasov authored 
      	In tcp_tw_remember_stamp we incorrectly checked tw
instead of tm, it can lead to oops if the cached entry is
not found.

	tcpm_stamp was not updated in tcpm_check_stamp when
tcpm_suck_dst was called, move the update into tcpm_suck_dst,
so that we do not call it infinitely on every next cache hit
after TCP_METRICS_TIMEOUT.
Signed-off-by: default avatarJulian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9a0a9502
    • Shuah Khan's avatar
      niu: Change niu_rbr_fill() to use unlikely() to check niu_rbr_add_page() return value · 9b70749e
      Shuah Khan authored 
      Change niu_rbr_fill() to use unlikely() to check niu_rbr_add_page() return
value to be consistent with the rest of the checks after niu_rbr_add_page()
calls in this file.
Signed-off-by: default avatarShuah Khan <shuah.khan@hp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9b70749e
    • Shuah Khan's avatar
      niu: Fix to check for dma mapping errors. · ec2deec1
      Shuah Khan authored 
      Fix Neptune ethernet driver to check dma mapping error after map_page()
interface returns.
Signed-off-by: default avatarShuah Khan <shuah.khan@hp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ec2deec1
    • Jesper Juhl's avatar
      net: Fix references to out-of-scope variables in put_cmsg_compat() · 81881047
      Jesper Juhl authored 
      In net/compat.c::put_cmsg_compat() we may assign 'data' the address of
either the 'ctv' or 'cts' local variables inside the 'if
(!COMPAT_USE_64BIT_TIME)' branch.

Those variables go out of scope at the end of the 'if' statement, so
when we use 'data' further down in 'copy_to_user(CMSG_COMPAT_DATA(cm),
data, cmlen - sizeof(struct compat_cmsghdr))' there's no telling what
it may be refering to - not good.

Fix the problem by simply giving 'ctv' and 'cts' function scope.
Signed-off-by: default avatarJesper Juhl <jj@chaosbits.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      81881047
    • David S. Miller's avatar
      Merge branch 'kill_rtcache' · 5e9965c1
      David S. Miller authored 
      The ipv4 routing cache is non-deterministic, performance wise, and is
subject to reasonably easy to launch denial of service attacks.

The routing cache works great for well behaved traffic, and the world
was a much friendlier place when the tradeoffs that led to the routing
cache's design were considered.

What it boils down to is that the performance of the routing cache is
a product of the traffic patterns seen by a system rather than being a
product of the contents of the routing tables.  The former of which is
controllable by external entitites.

Even for "well behaved" legitimate traffic, high volume sites can see
hit rates in the routing cache of only ~%10.

The general flow of this patch series is that first the routing cache
is removed.  We build a completely new rtable entry every lookup
request.

Next we make some simplifications due to the fact that removing the
routing cache causes several members of struct rtable to become no
longer necessary.

Then we need to make some amends such that we can legally cache
pre-constructed routes in the FIB nexthops.  Firstly, we need to
invalidate routes which are hit with nexthop exceptions.  Secondly we
have to change the semantics of rt->rt_gateway such that zero means
that the destination is on-link and non-zero otherwise.

Now that the preparations are ready, we start caching precomputed
routes in the FIB nexthops.  Output and input routes need different
kinds of care when determining if we can legally do such caching or
not.  The details are in the commit log messages for those changes.

The patch series then winds down with some more struct rtable
simplifications and other tidy ups that remove unnecessary overhead.

On a SPARC-T3 output route lookups are ~876 cycles.  Input route
lookups are ~1169 cycles with rpfilter disabled, and about ~1468
cycles with rpfilter enabled.

These measurements were taken with the kbench_mod test module in the
net_test_tools GIT tree:

git://git.kernel.org/pub/scm/linux/kernel/git/davem/net_test_tools.git

That GIT tree also includes a udpflood tester tool and stresses
route lookups on packet output.

For example, on the same SPARC-T3 system we can run:

	time ./udpflood -l 10000000 10.2.2.11

with routing cache:
real    1m21.955s       user    0m6.530s        sys     1m15.390s

without routing cache:
real    1m31.678s       user    0m6.520s        sys     1m25.140s

Performance undoubtedly can easily be improved further.

For example fib_table_lookup() performs a lot of excessive
computations with all the masking and shifting, some of it
conditionalized to deal with edge cases.

Also, Eric's no-ref optimization for input route lookups can be
re-instated for the FIB nexthop caching code path.  I would be really
pleased if someone would work on that.

In fact anyone suitable motivated can just fire up perf on the loading
of the test net_test_tools benchmark kernel module.  I spend much of
my time going:

bash# perf record insmod ./kbench_mod.ko dst=172.30.42.22 src=74.128.0.1 iif=2
bash# perf report

Thanks to helpful feedback from Joe Perches, Eric Dumazet, Ben
Hutchings, and others.
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      5e9965c1
  3. 22 Jul, 2012 22 commits
  5. 21 Jul, 2012 11 commits
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