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  1. 25 Aug, 2015 1 commit
    • Eric Dumazet's avatar
      tcp: fix slow start after idle vs TSO/GSO · 6f021c62
      Eric Dumazet authored 
      slow start after idle might reduce cwnd, but we perform this
after first packet was cooked and sent.

With TSO/GSO, it means that we might send a full TSO packet
even if cwnd should have been reduced to IW10.

Moving the SSAI check in skb_entail() makes sense, because
we slightly reduce number of times this check is done,
especially for large send() and TCP Small queue callbacks from
softirq context.

As Neal pointed out, we also need to perform the check
if/when receive window opens.

Tested:

Following packetdrill test demonstrates the problem
// Test of slow start after idle

`sysctl -q net.ipv4.tcp_slow_start_after_idle=1`

0.000 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
+0    setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
+0    bind(3, ..., ...) = 0
+0    listen(3, 1) = 0

+0    < S 0:0(0) win 65535 <mss 1000,sackOK,nop,nop,nop,wscale 7>
+0    > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 6>
+.100 < . 1:1(0) ack 1 win 511
+0    accept(3, ..., ...) = 4
+0    setsockopt(4, SOL_SOCKET, SO_SNDBUF, [200000], 4) = 0

+0    write(4, ..., 26000) = 26000
+0    > . 1:5001(5000) ack 1
+0    > . 5001:10001(5000) ack 1
+0    %{ assert tcpi_snd_cwnd == 10 }%

+.100 < . 1:1(0) ack 10001 win 511
+0    %{ assert tcpi_snd_cwnd == 20, tcpi_snd_cwnd }%
+0    > . 10001:20001(10000) ack 1
+0    > P. 20001:26001(6000) ack 1

+.100 < . 1:1(0) ack 26001 win 511
+0    %{ assert tcpi_snd_cwnd == 36, tcpi_snd_cwnd }%

+4 write(4, ..., 20000) = 20000
// If slow start after idle works properly, we should send 5 MSS here (cwnd/2)
+0    > . 26001:31001(5000) ack 1
+0    %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }%
+0    > . 31001:36001(5000) ack 1
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      6f021c62
  3. 24 Aug, 2015 29 commits
  5. 23 Aug, 2015 10 commits
    • Jiri Benc's avatar
      route: fix breakage after moving lwtunnel state · 751a587a
      Jiri Benc authored 
      __recnt and related fields need to be in its own cacheline for performance
reasons. Commit 61adedf3 ("route: move lwtunnel state to dst_entry")
broke that on 32bit archs, causing BUILD_BUG_ON in dst_hold to be triggered.

This patch fixes the breakage by moving the lwtunnel state to the end of
dst_entry on 32bit archs. Unfortunately, this makes it share the cacheline
with __refcnt and may affect performance, thus further patches may be
needed.
Reported-by: default avatarkbuild test robot <fengguang.wu@intel.com>
Fixes: 61adedf3 ("route: move lwtunnel state to dst_entry")
Signed-off-by: default avatarJiri Benc <jbenc@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      751a587a
    • David S. Miller's avatar
      Merge tag 'linux-can-next-for-4.3-20150820' of... · 31fbde99
      David S. Miller authored 
      Merge tag 'linux-can-next-for-4.3-20150820' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next

Marc Kleine-Budde says:

====================
this is a pull request of a two patches for net-next.

The first patch is by Nik Nyby and fixes a typo in a function name. The
second patch by Lucas Stach demotes register output to debug level.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      31fbde99
    • David S. Miller's avatar
      Merge branch 'tipc-failover-fixes' · c5f98b56
      David S. Miller authored 
      Jon Maloy says:

====================
tipc: fix link failover/synch problems

We fix three problems with the new link failover/synch implementation,
which was introduced earlier in this release cycle. They are all related
to situations where there is a very short interval between the disabling
and enabling of interfaces.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c5f98b56
    • Jon Paul Maloy's avatar
      tipc: fix stale link problem during synchronization · 2be80c2d
      Jon Paul Maloy authored 
      Recent changes to the link synchronization means that we can now just
drop packets arriving on the synchronizing link before the synch point
is reached. This has lead to significant simplifications to the
implementation, but also turns out to have a flip side that we need
to consider.

Under unlucky circumstances, the two endpoints may end up
repeatedly dropping each other's packets, while immediately
asking for retransmission of the same packets, just to drop
them once more. This pattern will eventually be broken when
the synch point is reached on the other link, but before that,
the endpoints may have arrived at the retransmission limit
(stale counter) that indicates that the link should be broken.
We see this happen at rare occasions.

The fix for this is to not ask for retransmissions when a link is in
state LINK_SYNCHING. The fact that the link has reached this state
means that it has already received the first SYNCH packet, and that it
knows the synch point. Hence, it doesn't need any more packets until the
other link has reached the synch point, whereafter it can go ahead and
ask for the missing packets.

However, because of the reduced traffic on the synching link that
follows this change, it may now take longer to discover that the
synch point has been reached. We compensate for this by letting all
packets, on any of the links, trig a check for synchronization
termination. This is possible because the packets themselves don't
contain any information that is needed for discovering this condition.
Reviewed-by: default avatarYing Xue <ying.xue@windriver.com>
Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      2be80c2d
    • Jon Paul Maloy's avatar
      tipc: interrupt link synchronization when a link goes down · 5ae2f8e6
      Jon Paul Maloy authored 
      When we introduced the new link failover/synch mechanism
in commit 6e498158
("tipc: move link synch and failover to link aggregation level"),
we missed the case when the non-tunnel link goes down during the link
synchronization period. In this case the tunnel link will remain in
state LINK_SYNCHING, something leading to unpredictable behavior when
the failover procedure is initiated.

In this commit, we ensure that the node and remaining link goes
back to regular communication state (SELF_UP_PEER_UP/LINK_ESTABLISHED)
when one of the parallel links goes down. We also ensure that we don't
re-enter synch mode if subsequent SYNCH packets arrive on the remaining
link.
Reviewed-by: default avatarYing Xue <ying.xue@windriver.com>
Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      5ae2f8e6
    • Jon Paul Maloy's avatar
      tipc: eliminate risk of premature link setup during failover · 17b20630
      Jon Paul Maloy authored 
      When a link goes down, and there is still a working link towards its
destination node, a failover is initiated, and the failed link is not
allowed to re-establish until that procedure is finished. To ensure
this, the concerned link endpoints are set to state LINK_FAILINGOVER,
and the node endpoints to NODE_FAILINGOVER during the failover period.

However, if the link reset is due to a disabled bearer, the corres-
ponding link endpoint is deleted, and only the node endpoint knows
about the ongoing failover. Now, if the disabled bearer is re-enabled
during the failover period, the discovery mechanism may create a new
link endpoint that is ready to be established, despite that this is not
permitted. This situation may cause both the ongoing failover and any
subsequent link synchronization to fail.

In this commit, we ensure that a newly created link goes directly to
state LINK_FAILINGOVER if the corresponding node state is
NODE_FAILINGOVER. This eliminates the problem described above.

Furthermore, we tighten the criteria for which packets are allowed
to end a failover state in the function tipc_node_check_state().
By checking that the receiving link is up and running, instead of just
checking that it is not in failover mode, we eliminate the risk that
protocol packets from the re-created link may cause the failover to
be prematurely terminated.
Reviewed-by: default avatarYing Xue <ying.xue@windriver.com>
Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      17b20630
    • David S. Miller's avatar
      Merge branch 'nps_enet_fixes' · 7f629be1
      David S. Miller authored 
      Noam Camus says:

====================
*** nps_enet fixups ***

Change v2
TX done is handled back with NAPI poll.

Change v1
This patch set is a bunch of fixes to make nps_enet work correctly with
all platforms, i.e. real device, emulation system, and simulation system.
The main trigger for this patch set was that in our emulation system
the TX end interrupt is "edge-sensitive" and therefore we cannot use the
cause register since it is not sticky.
Also:
TX is handled during HW interrupt context and not NAPI job.
race with TX done was fixed.
added acknowledge for TX when device is "level sensitive".
enable drop of control frames which is not needed for regular usage.

So most of this patch set is about TX handling, which is now more complete.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      7f629be1
    • Noam Camus's avatar
      NET: nps_enet: minor namespace cleanup · 41493795
      Noam Camus authored 
      We define buf_int_enable in the minimal namespace it is used.
Signed-off-by: default avatarNoam Camus <noamc@ezchip.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      41493795
    • Noam Camus's avatar
      NET: nps_enet: TX done acknowledge. · 3d99b74a
      Noam Camus authored 
      This is needed for when TX done interrupt is in
"level mode".
For example it is true for some simulators of this device.
Signed-off-by: default avatarNoam Camus <noamc@ezchip.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      3d99b74a
    • Noam Camus's avatar
      NET: nps_enet: drop control frames · de671567
      Noam Camus authored 
      We set controller to drop control frames and not trying
to pass them on. This is only needed for debug reasons.
Signed-off-by: default avatarNoam Camus <noamc@ezchip.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      de671567
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