1. 14 10月, 2011 1 次提交
    • E
      net: more accurate skb truesize · 87fb4b7b
      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
  2. 05 10月, 2011 1 次提交
    • Y
      tcp: properly update lost_cnt_hint during shifting · 1e5289e1
      Yan, Zheng 提交于
      lost_skb_hint is used by tcp_mark_head_lost() to mark the first unhandled skb.
      lost_cnt_hint is the number of packets or sacked packets before the lost_skb_hint;
      When shifting a skb that is before the lost_skb_hint, if tcp_is_fack() is ture,
      the skb has already been counted in the lost_cnt_hint; if tcp_is_fack() is false,
      tcp_sacktag_one() will increase the lost_cnt_hint. So tcp_shifted_skb() does not
      need to adjust the lost_cnt_hint by itself. When shifting a skb that is equal to
      lost_skb_hint, the shifted packets will not be counted by tcp_mark_head_lost().
      So tcp_shifted_skb() should adjust the lost_cnt_hint even tcp_is_fack(tp) is true.
      Signed-off-by: NZheng Yan <zheng.z.yan@intel.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1e5289e1
  3. 28 9月, 2011 1 次提交
  4. 27 9月, 2011 2 次提交
  5. 19 9月, 2011 1 次提交
  6. 25 8月, 2011 1 次提交
    • N
      Proportional Rate Reduction for TCP. · a262f0cd
      Nandita Dukkipati 提交于
      This patch implements Proportional Rate Reduction (PRR) for TCP.
      PRR is an algorithm that determines TCP's sending rate in fast
      recovery. PRR avoids excessive window reductions and aims for
      the actual congestion window size at the end of recovery to be as
      close as possible to the window determined by the congestion control
      algorithm. PRR also improves accuracy of the amount of data sent
      during loss recovery.
      
      The patch implements the recommended flavor of PRR called PRR-SSRB
      (Proportional rate reduction with slow start reduction bound) and
      replaces the existing rate halving algorithm. PRR improves upon the
      existing Linux fast recovery under a number of conditions including:
        1) burst losses where the losses implicitly reduce the amount of
      outstanding data (pipe) below the ssthresh value selected by the
      congestion control algorithm and,
        2) losses near the end of short flows where application runs out of
      data to send.
      
      As an example, with the existing rate halving implementation a single
      loss event can cause a connection carrying short Web transactions to
      go into the slow start mode after the recovery. This is because during
      recovery Linux pulls the congestion window down to packets_in_flight+1
      on every ACK. A short Web response often runs out of new data to send
      and its pipe reduces to zero by the end of recovery when all its packets
      are drained from the network. Subsequent HTTP responses using the same
      connection will have to slow start to raise cwnd to ssthresh. PRR on
      the other hand aims for the cwnd to be as close as possible to ssthresh
      by the end of recovery.
      
      A description of PRR and a discussion of its performance can be found at
      the following links:
      - IETF Draft:
          http://tools.ietf.org/html/draft-mathis-tcpm-proportional-rate-reduction-01
      - IETF Slides:
          http://www.ietf.org/proceedings/80/slides/tcpm-6.pdf
          http://tools.ietf.org/agenda/81/slides/tcpm-2.pdf
      - Paper to appear in Internet Measurements Conference (IMC) 2011:
          Improving TCP Loss Recovery
          Nandita Dukkipati, Matt Mathis, Yuchung Cheng
      Signed-off-by: NNandita Dukkipati <nanditad@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      a262f0cd
  7. 09 6月, 2011 1 次提交
    • J
      tcp: RFC2988bis + taking RTT sample from 3WHS for the passive open side · 9ad7c049
      Jerry Chu 提交于
      This patch lowers the default initRTO from 3secs to 1sec per
      RFC2988bis. It falls back to 3secs if the SYN or SYN-ACK packet
      has been retransmitted, AND the TCP timestamp option is not on.
      
      It also adds support to take RTT sample during 3WHS on the passive
      open side, just like its active open counterpart, and uses it, if
      valid, to seed the initRTO for the data transmission phase.
      
      The patch also resets ssthresh to its initial default at the
      beginning of the data transmission phase, and reduces cwnd to 1 if
      there has been MORE THAN ONE retransmission during 3WHS per RFC5681.
      Signed-off-by: NH.K. Jerry Chu <hkchu@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      9ad7c049
  8. 23 3月, 2011 2 次提交
  9. 15 3月, 2011 1 次提交
    • S
      tcp: fix RTT for quick packets in congestion control · febf0819
      stephen hemminger 提交于
      In the congestion control interface, the callback for each ACK
      includes an estimated round trip time in microseconds.
      Some algorithms need high resolution (Vegas style) but most only
      need jiffie resolution.  If RTT is not accurate (like a retransmission)
      -1 is used as a flag value.
      
      When doing coarse resolution if RTT is less than a a jiffie
      then 0 should be returned rather than no estimate. Otherwise algorithms
      that expect good ack's to trigger slow start (like CUBIC Hystart)
      will be confused.
      Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      febf0819
  10. 22 2月, 2011 1 次提交
  11. 03 2月, 2011 1 次提交
  12. 26 1月, 2011 1 次提交
    • J
      TCP: fix a bug that triggers large number of TCP RST by mistake · 44f5324b
      Jerry Chu 提交于
      This patch fixes a bug that causes TCP RST packets to be generated
      on otherwise correctly behaved applications, e.g., no unread data
      on close,..., etc. To trigger the bug, at least two conditions must
      be met:
      
      1. The FIN flag is set on the last data packet, i.e., it's not on a
      separate, FIN only packet.
      2. The size of the last data chunk on the receive side matches
      exactly with the size of buffer posted by the receiver, and the
      receiver closes the socket without any further read attempt.
      
      This bug was first noticed on our netperf based testbed for our IW10
      proposal to IETF where a large number of RST packets were observed.
      netperf's read side code meets the condition 2 above 100%.
      
      Before the fix, tcp_data_queue() will queue the last skb that meets
      condition 1 to sk_receive_queue even though it has fully copied out
      (skb_copy_datagram_iovec()) the data. Then if condition 2 is also met,
      tcp_recvmsg() often returns all the copied out data successfully
      without actually consuming the skb, due to a check
      "if ((chunk = len - tp->ucopy.len) != 0) {"
      and
      "len -= chunk;"
      after tcp_prequeue_process() that causes "len" to become 0 and an
      early exit from the big while loop.
      
      I don't see any reason not to free the skb whose data have been fully
      consumed in tcp_data_queue(), regardless of the FIN flag.  We won't
      get there if MSG_PEEK is on. Am I missing some arcane cases related
      to urgent data?
      Signed-off-by: NH.K. Jerry Chu <hkchu@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      44f5324b
  13. 24 12月, 2010 1 次提交
  14. 10 12月, 2010 1 次提交
    • D
      net: Abstract away all dst_entry metrics accesses. · defb3519
      David S. Miller 提交于
      Use helper functions to hide all direct accesses, especially writes,
      to dst_entry metrics values.
      
      This will allow us to:
      
      1) More easily change how the metrics are stored.
      
      2) Implement COW for metrics.
      
      In particular this will help us put metrics into the inetpeer
      cache if that is what we end up doing.  We can make the _metrics
      member a pointer instead of an array, initially have it point
      at the read-only metrics in the FIB, and then on the first set
      grab an inetpeer entry and point the _metrics member there.
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
      defb3519
  15. 11 11月, 2010 1 次提交
  16. 18 10月, 2010 2 次提交
  17. 07 10月, 2010 1 次提交
  18. 30 9月, 2010 1 次提交
  19. 28 9月, 2010 1 次提交
  20. 24 9月, 2010 1 次提交
  21. 21 9月, 2010 1 次提交
  22. 31 8月, 2010 1 次提交
  23. 08 8月, 2010 1 次提交
  24. 13 7月, 2010 1 次提交
  25. 16 6月, 2010 1 次提交
    • C
      tcp: unify tcp flag macros · a3433f35
      Changli Gao 提交于
      unify tcp flag macros: TCPHDR_FIN, TCPHDR_SYN, TCPHDR_RST, TCPHDR_PSH,
      TCPHDR_ACK, TCPHDR_URG, TCPHDR_ECE and TCPHDR_CWR. TCBCB_FLAG_* are replaced
      with the corresponding TCPHDR_*.
      Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
      ----
       include/net/tcp.h                      |   24 ++++++-------
       net/ipv4/tcp.c                         |    8 ++--
       net/ipv4/tcp_input.c                   |    2 -
       net/ipv4/tcp_output.c                  |   59 ++++++++++++++++-----------------
       net/netfilter/nf_conntrack_proto_tcp.c |   32 ++++++-----------
       net/netfilter/xt_TCPMSS.c              |    4 --
       6 files changed, 58 insertions(+), 71 deletions(-)
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      a3433f35
  26. 01 6月, 2010 1 次提交
  27. 18 5月, 2010 1 次提交
  28. 29 4月, 2010 1 次提交
  29. 13 4月, 2010 1 次提交
    • E
      net: sk_dst_cache RCUification · b6c6712a
      Eric Dumazet 提交于
      With latest CONFIG_PROVE_RCU stuff, I felt more comfortable to make this
      work.
      
      sk->sk_dst_cache is currently protected by a rwlock (sk_dst_lock)
      
      This rwlock is readlocked for a very small amount of time, and dst
      entries are already freed after RCU grace period. This calls for RCU
      again :)
      
      This patch converts sk_dst_lock to a spinlock, and use RCU for readers.
      
      __sk_dst_get() is supposed to be called with rcu_read_lock() or if
      socket locked by user, so use appropriate rcu_dereference_check()
      condition (rcu_read_lock_held() || sock_owned_by_user(sk))
      
      This patch avoids two atomic ops per tx packet on UDP connected sockets,
      for example, and permits sk_dst_lock to be much less dirtied.
      Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      b6c6712a
  30. 30 3月, 2010 1 次提交
    • T
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      Tejun Heo 提交于
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
      
      percpu.h is included by sched.h and module.h and thus ends up being
      included when building most .c files.  percpu.h includes slab.h which
      in turn includes gfp.h making everything defined by the two files
      universally available and complicating inclusion dependencies.
      
      percpu.h -> slab.h dependency is about to be removed.  Prepare for
      this change by updating users of gfp and slab facilities include those
      headers directly instead of assuming availability.  As this conversion
      needs to touch large number of source files, the following script is
      used as the basis of conversion.
      
        http://userweb.kernel.org/~tj/misc/slabh-sweep.py
      
      The script does the followings.
      
      * Scan files for gfp and slab usages and update includes such that
        only the necessary includes are there.  ie. if only gfp is used,
        gfp.h, if slab is used, slab.h.
      
      * When the script inserts a new include, it looks at the include
        blocks and try to put the new include such that its order conforms
        to its surrounding.  It's put in the include block which contains
        core kernel includes, in the same order that the rest are ordered -
        alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
        doesn't seem to be any matching order.
      
      * If the script can't find a place to put a new include (mostly
        because the file doesn't have fitting include block), it prints out
        an error message indicating which .h file needs to be added to the
        file.
      
      The conversion was done in the following steps.
      
      1. The initial automatic conversion of all .c files updated slightly
         over 4000 files, deleting around 700 includes and adding ~480 gfp.h
         and ~3000 slab.h inclusions.  The script emitted errors for ~400
         files.
      
      2. Each error was manually checked.  Some didn't need the inclusion,
         some needed manual addition while adding it to implementation .h or
         embedding .c file was more appropriate for others.  This step added
         inclusions to around 150 files.
      
      3. The script was run again and the output was compared to the edits
         from #2 to make sure no file was left behind.
      
      4. Several build tests were done and a couple of problems were fixed.
         e.g. lib/decompress_*.c used malloc/free() wrappers around slab
         APIs requiring slab.h to be added manually.
      
      5. The script was run on all .h files but without automatically
         editing them as sprinkling gfp.h and slab.h inclusions around .h
         files could easily lead to inclusion dependency hell.  Most gfp.h
         inclusion directives were ignored as stuff from gfp.h was usually
         wildly available and often used in preprocessor macros.  Each
         slab.h inclusion directive was examined and added manually as
         necessary.
      
      6. percpu.h was updated not to include slab.h.
      
      7. Build test were done on the following configurations and failures
         were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
         distributed build env didn't work with gcov compiles) and a few
         more options had to be turned off depending on archs to make things
         build (like ipr on powerpc/64 which failed due to missing writeq).
      
         * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
         * powerpc and powerpc64 SMP allmodconfig
         * sparc and sparc64 SMP allmodconfig
         * ia64 SMP allmodconfig
         * s390 SMP allmodconfig
         * alpha SMP allmodconfig
         * um on x86_64 SMP allmodconfig
      
      8. percpu.h modifications were reverted so that it could be applied as
         a separate patch and serve as bisection point.
      
      Given the fact that I had only a couple of failures from tests on step
      6, I'm fairly confident about the coverage of this conversion patch.
      If there is a breakage, it's likely to be something in one of the arch
      headers which should be easily discoverable easily on most builds of
      the specific arch.
      Signed-off-by: NTejun Heo <tj@kernel.org>
      Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      5a0e3ad6
  31. 25 3月, 2010 1 次提交
  32. 20 3月, 2010 1 次提交
  33. 19 2月, 2010 1 次提交
    • A
      net: TCP thin dupack · 7e380175
      Andreas Petlund 提交于
      This patch enables fast retransmissions after one dupACK for
      TCP if the stream is identified as thin. This will reduce
      latencies for thin streams that are not able to trigger fast
      retransmissions due to high packet interarrival time. This
      mechanism is only active if enabled by iocontrol or syscontrol
      and the stream is identified as thin.
      Signed-off-by: NAndreas Petlund <apetlund@simula.no>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      7e380175
  34. 11 2月, 2010 1 次提交
    • D
      tcp: fix ICMP-RTO war · 59885640
      Damian Lukowski 提交于
      Make sure, that TCP has a nonzero RTT estimation after three-way
      handshake. Currently, a listening TCP has a value of 0 for srtt,
      rttvar and rto right after the three-way handshake is completed
      with TCP timestamps disabled.
      This will lead to corrupt RTO recalculation and retransmission
      flood when RTO is recalculated on backoff reversion as introduced
      in "Revert RTO on ICMP destination unreachable"
      (f1ecd5d9).
      This behaviour can be provoked by connecting to a server which
      "responds first" (like SMTP) and rejecting every packet after
      the handshake with dest-unreachable, which will lead to softirq
      load on the server (up to 30% per socket in some tests).
      
      Thanks to Ilpo Jarvinen for providing debug patches and to
      Denys Fedoryshchenko for reporting and testing.
      
      Changes since v3: Removed bad characters in patchfile.
      Reported-by: NDenys Fedoryshchenko <denys@visp.net.lb>
      Signed-off-by: NDamian Lukowski <damian@tvk.rwth-aachen.de>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      59885640
  35. 16 12月, 2009 1 次提交
    • D
      tcp: Revert per-route SACK/DSACK/TIMESTAMP changes. · bb5b7c11
      David S. Miller 提交于
      It creates a regression, triggering badness for SYN_RECV
      sockets, for example:
      
      [19148.022102] Badness at net/ipv4/inet_connection_sock.c:293
      [19148.022570] NIP: c02a0914 LR: c02a0904 CTR: 00000000
      [19148.023035] REGS: eeecbd30 TRAP: 0700   Not tainted  (2.6.32)
      [19148.023496] MSR: 00029032 <EE,ME,CE,IR,DR>  CR: 24002442  XER: 00000000
      [19148.024012] TASK = eee9a820[1756] 'privoxy' THREAD: eeeca000
      
      This is likely caused by the change in the 'estab' parameter
      passed to tcp_parse_options() when invoked by the functions
      in net/ipv4/tcp_minisocks.c
      
      But even if that is fixed, the ->conn_request() changes made in
      this patch series is fundamentally wrong.  They try to use the
      listening socket's 'dst' to probe the route settings.  The
      listening socket doesn't even have a route, and you can't
      get the right route (the child request one) until much later
      after we setup all of the state, and it must be done by hand.
      
      This stuff really isn't ready, so the best thing to do is a
      full revert.  This reverts the following commits:
      
      f55017a9
      022c3f7d
      1aba721e
      cda42ebd
      345cda2f
      dc343475
      05eaade2
      6a2a2d6bSigned-off-by: NDavid S. Miller <davem@davemloft.net>
      bb5b7c11
  36. 09 12月, 2009 1 次提交
    • I
      tcp: fix retrans_stamp advancing in error cases · 77722b17
      Ilpo Järvinen 提交于
      It can happen, that tcp_retransmit_skb fails due to some error.
      In such cases we might end up into a state where tp->retrans_out
      is zero but that's only because we removed the TCPCB_SACKED_RETRANS
      bit from a segment but couldn't retransmit it because of the error
      that happened. Therefore some assumptions that retrans_out checks
      are based do not necessarily hold, as there still can be an old
      retransmission but that is only visible in TCPCB_EVER_RETRANS bit.
      As retransmission happen in sequential order (except for some very
      rare corner cases), it's enough to check the head skb for that bit.
      
      Main reason for all this complexity is the fact that connection dying
      time now depends on the validity of the retrans_stamp, in particular,
      that successive retransmissions of a segment must not advance
      retrans_stamp under any conditions. It seems after quick thinking that
      this has relatively low impact as eventually TCP will go into CA_Loss
      and either use the existing check for !retrans_stamp case or send a
      retransmission successfully, setting a new base time for the dying
      timer (can happen only once). At worst, the dying time will be
      approximately the double of the intented time. In addition,
      tcp_packet_delayed() will return wrong result (has some cc aspects
      but due to rarity of these errors, it's hardly an issue).
      
      One of retrans_stamp clearing happens indirectly through first going
      into CA_Open state and then a later ACK lets the clearing to happen.
      Thus tcp_try_keep_open has to be modified too.
      
      Thanks to Damian Lukowski <damian@tvk.rwth-aachen.de> for hinting
      that this possibility exists (though the particular case discussed
      didn't after all have it happening but was just a debug patch
      artifact).
      Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      77722b17
  37. 03 12月, 2009 1 次提交
    • W
      TCPCT part 1g: Responder Cookie => Initiator · 4957faad
      William Allen Simpson 提交于
      Parse incoming TCP_COOKIE option(s).
      
      Calculate <SYN,ACK> TCP_COOKIE option.
      
      Send optional <SYN,ACK> data.
      
      This is a significantly revised implementation of an earlier (year-old)
      patch that no longer applies cleanly, with permission of the original
      author (Adam Langley):
      
          http://thread.gmane.org/gmane.linux.network/102586
      
      Requires:
         TCPCT part 1a: add request_values parameter for sending SYNACK
         TCPCT part 1b: generate Responder Cookie secret
         TCPCT part 1c: sysctl_tcp_cookie_size, socket option TCP_COOKIE_TRANSACTIONS
         TCPCT part 1d: define TCP cookie option, extend existing struct's
         TCPCT part 1e: implement socket option TCP_COOKIE_TRANSACTIONS
         TCPCT part 1f: Initiator Cookie => Responder
      
      Signed-off-by: William.Allen.Simpson@gmail.com
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      4957faad