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  1. 24 Feb, 2014 16 commits
  3. 21 Feb, 2014 17 commits
  5. 20 Feb, 2014 4 commits
  7. 19 Feb, 2014 3 commits
    • Florian Westphal's avatar
      tcp: use zero-window when free_space is low · 86c1a045
      Florian Westphal authored 
      Currently the kernel tries to announce a zero window when free_space
is below the current receiver mss estimate.

When a sender is transmitting small packets and reader consumes data
slowly (or not at all), receiver might be unable to shrink the receive
win because

a) we cannot withdraw already-commited receive window, and,
b) we have to round the current rwin up to a multiple of the wscale
   factor, else we would shrink the current window.

This causes the receive buffer to fill up until the rmem limit is hit.
When this happens, we start dropping packets.

Moreover, tcp_clamp_window may continue to grow sk_rcvbuf towards rmem[2]
even if socket is not being read from.

As we cannot avoid the "current_win is rounded up to multiple of mss"
issue [we would violate a) above] at least try to prevent the receive buf
growth towards tcp_rmem[2] limit by attempting to move to zero-window
announcement when free_space becomes less than 1/16 of the current
allowed receive buffer maximum.  If tcp_rmem[2] is large, this will
increase our chances to get a zero-window announcement out in time.

Reproducer:
On server:
$ nc -l -p 12345
<suspend it: CTRL-Z>

Client:
#!/usr/bin/env python
import socket
import time

sock = socket.socket()
sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
sock.connect(("192.168.4.1", 12345));
while True:
   sock.send('A' * 23)
   time.sleep(0.005)

socket buffer on server-side will grow until tcp_rmem[2] is hit,
at which point the client rexmits data until -EDTIMEOUT:

tcp_data_queue invokes tcp_try_rmem_schedule which will call
tcp_prune_queue which calls tcp_clamp_window().  And that function will
grow sk->sk_rcvbuf up until it eventually hits tcp_rmem[2].

Thanks to Eric Dumazet for running regression tests.

Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Tested-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      86c1a045
    • Erik Hugne's avatar
      tipc: failed transmissions should return error · 63fa01c1
      Erik Hugne authored 
      When a message could not be sent out because the destination node
or link could not be found, the full message size is returned from
sendmsg() as if it had been sent successfully. An application will
then get a false indication that it's making forward progress. This
problem has existed since the initial commit in 2.6.16.

We change this to return -ENETUNREACH if the message cannot be
delivered due to the destination node/link being unavailable. We
also get rid of the redundant tipc_reject_msg call since freeing
the buffer and doing a tipc_port_iovec_reject accomplishes exactly
the same thing.
Signed-off-by: default avatarErik Hugne <erik.hugne@ericsson.com>
Reviewed-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      63fa01c1
    • Daeseok Youn's avatar
      atm: solos-pci: make solos_bh() as static · 5f4d4e3f
      Daeseok Youn authored 
      sparse says:

drivers/atm/solos-pci.c:763:6: warning:
 symbol 'solos_bh' was not declared. Should it be static?
Signed-off-by: default avatarDaeseok Youn <daeseok.youn@gmail.com>
Acked-by: default avatarChas Williams <chas@cmf.nrl.navy.mil>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      5f4d4e3f
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