1. 21 3月, 2015 3 次提交
    • E
      net: increase sk_[max_]ack_backlog · becb74f0
      Eric Dumazet 提交于
      sk_ack_backlog & sk_max_ack_backlog were 16bit fields, meaning
      listen() backlog was limited to 65535.
      
      It is time to increase the width to allow much bigger backlog,
      if admins change /proc/sys/net/core/somaxconn &
      /proc/sys/net/ipv4/tcp_max_syn_backlog default values.
      
      Tested:
      
      echo 5000000 >/proc/sys/net/core/somaxconn
      echo 5000000 >/proc/sys/net/ipv4/tcp_max_syn_backlog
      
      Ran a SYNFLOOD test against a listener using listen(fd, 5000000)
      
      myhost~# grep request_sock_TCP /proc/slabinfo
      request_sock_TCP  4185642 4411940    304   13    1 : tunables   54   27    8 : slabdata 339380 339380      0
      Signed-off-by: NEric Dumazet <edumazet@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      becb74f0
    • E
      inet: get rid of central tcp/dccp listener timer · fa76ce73
      Eric Dumazet 提交于
      One of the major issue for TCP is the SYNACK rtx handling,
      done by inet_csk_reqsk_queue_prune(), fired by the keepalive
      timer of a TCP_LISTEN socket.
      
      This function runs for awful long times, with socket lock held,
      meaning that other cpus needing this lock have to spin for hundred of ms.
      
      SYNACK are sent in huge bursts, likely to cause severe drops anyway.
      
      This model was OK 15 years ago when memory was very tight.
      
      We now can afford to have a timer per request sock.
      
      Timer invocations no longer need to lock the listener,
      and can be run from all cpus in parallel.
      
      With following patch increasing somaxconn width to 32 bits,
      I tested a listener with more than 4 million active request sockets,
      and a steady SYNFLOOD of ~200,000 SYN per second.
      Host was sending ~830,000 SYNACK per second.
      
      This is ~100 times more what we could achieve before this patch.
      
      Later, we will get rid of the listener hash and use ehash instead.
      Signed-off-by: NEric Dumazet <edumazet@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      fa76ce73
    • E
      inet: drop prev pointer handling in request sock · 52452c54
      Eric Dumazet 提交于
      When request sock are put in ehash table, the whole notion
      of having a previous request to update dl_next is pointless.
      
      Also, following patch will get rid of big purge timer,
      so we want to delete a request sock without holding listener lock.
      Signed-off-by: NEric Dumazet <edumazet@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      52452c54
  2. 20 3月, 2015 11 次提交
  3. 19 3月, 2015 26 次提交