1. 30 Nov, 2012 1 commit
    • Eric Dumazet's avatar
      net: move inet_dport/inet_num in sock_common · ce43b03e
      Eric Dumazet authored
      commit 68835aba (net: optimize INET input path further)
      moved some fields used for tcp/udp sockets lookup in the first cache
      line of struct sock_common.
      
      This patch moves inet_dport/inet_num as well, filling a 32bit hole
      on 64 bit arches and reducing number of cache line misses in lookups.
      
      Also change INET_MATCH()/INET_TW_MATCH() to perform the ports match
      before addresses match, as this check is more discriminant.
      
      Remove the hash check from MATCH() macros because we dont need to
      re validate the hash value after taking a refcount on socket, and
      use likely/unlikely compiler hints, as the sk_hash/hash check
      makes the following conditional tests 100% predicted by cpu.
      
      Introduce skc_addrpair/skc_portpair pair values to better
      document the alignment requirements of the port/addr pairs
      used in the various MATCH() macros, and remove some casts.
      
      The namespace check can also be done at last.
      
      This slightly improves TCP/UDP lookup times.
      
      IP/TCP early demux needs inet->rx_dst_ifindex and
      TCP needs inet->min_ttl, lets group them together in same cache line.
      
      With help from Ben Hutchings & Joe Perches.
      
      Idea of this patch came after Ling Ma proposal to move skc_hash
      to the beginning of struct sock_common, and should allow him
      to submit a final version of his patch. My tests show an improvement
      doing so.
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Cc: Ben Hutchings <bhutchings@solarflare.com>
      Cc: Joe Perches <joe@perches.com>
      Cc: Ling Ma <ling.ma.program@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ce43b03e
  2. 15 Apr, 2012 1 commit
  3. 06 Aug, 2011 1 commit
    • David S. Miller's avatar
      net: Compute protocol sequence numbers and fragment IDs using MD5. · 6e5714ea
      David S. Miller authored
      Computers have become a lot faster since we compromised on the
      partial MD4 hash which we use currently for performance reasons.
      
      MD5 is a much safer choice, and is inline with both RFC1948 and
      other ISS generators (OpenBSD, Solaris, etc.)
      
      Furthermore, only having 24-bits of the sequence number be truly
      unpredictable is a very serious limitation.  So the periodic
      regeneration and 8-bit counter have been removed.  We compute and
      use a full 32-bit sequence number.
      
      For ipv6, DCCP was found to use a 32-bit truncated initial sequence
      number (it needs 43-bits) and that is fixed here as well.
      Reported-by: default avatarDan Kaminsky <dan@doxpara.com>
      Tested-by: default avatarWilly Tarreau <w@1wt.eu>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      6e5714ea
  4. 28 Nov, 2010 1 commit
  5. 21 Oct, 2010 1 commit
  6. 12 Jul, 2010 1 commit
  7. 16 May, 2010 1 commit
  8. 08 Dec, 2009 2 commits
  9. 03 Dec, 2009 1 commit
    • Eric Dumazet's avatar
      tcp: connect() race with timewait reuse · 13475a30
      Eric Dumazet authored
      Its currently possible that several threads issuing a connect() find
      the same timewait socket and try to reuse it, leading to list
      corruptions.
      
      Condition for bug is that these threads bound their socket on same
      address/port of to-be-find timewait socket, and connected to same
      target. (SO_REUSEADDR needed)
      
      To fix this problem, we could unhash timewait socket while holding
      ehash lock, to make sure lookups/changes will be serialized. Only
      first thread finds the timewait socket, other ones find the
      established socket and return an EADDRNOTAVAIL error.
      
      This second version takes into account Evgeniy's review and makes sure
      inet_twsk_put() is called outside of locked sections.
      Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      13475a30
  10. 25 Nov, 2009 1 commit
  11. 18 Oct, 2009 1 commit
    • Eric Dumazet's avatar
      inet: rename some inet_sock fields · c720c7e8
      Eric Dumazet authored
      In order to have better cache layouts of struct sock (separate zones
      for rx/tx paths), we need this preliminary patch.
      
      Goal is to transfert fields used at lookup time in the first
      read-mostly cache line (inside struct sock_common) and move sk_refcnt
      to a separate cache line (only written by rx path)
      
      This patch adds inet_ prefix to daddr, rcv_saddr, dport, num, saddr,
      sport and id fields. This allows a future patch to define these
      fields as macros, like sk_refcnt, without name clashes.
      Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c720c7e8
  12. 13 Oct, 2009 1 commit
  13. 01 Feb, 2009 1 commit
  14. 21 Jan, 2009 1 commit
    • Evgeniy Polyakov's avatar
      inet: Allowing more than 64k connections and heavily optimize bind(0) time. · a9d8f911
      Evgeniy Polyakov authored
      With simple extension to the binding mechanism, which allows to bind more
      than 64k sockets (or smaller amount, depending on sysctl parameters),
      we have to traverse the whole bind hash table to find out empty bucket.
      And while it is not a problem for example for 32k connections, bind()
      completion time grows exponentially (since after each successful binding
      we have to traverse one bucket more to find empty one) even if we start
      each time from random offset inside the hash table.
      
      So, when hash table is full, and we want to add another socket, we have
      to traverse the whole table no matter what, so effectivelly this will be
      the worst case performance and it will be constant.
      
      Attached picture shows bind() time depending on number of already bound
      sockets.
      
      Green area corresponds to the usual binding to zero port process, which
      turns on kernel port selection as described above. Red area is the bind
      process, when number of reuse-bound sockets is not limited by 64k (or
      sysctl parameters). The same exponential growth (hidden by the green
      area) before number of ports reaches sysctl limit.
      
      At this time bind hash table has exactly one reuse-enbaled socket in a
      bucket, but it is possible that they have different addresses. Actually
      kernel selects the first port to try randomly, so at the beginning bind
      will take roughly constant time, but with time number of port to check
      after random start will increase. And that will have exponential growth,
      but because of above random selection, not every next port selection
      will necessary take longer time than previous. So we have to consider
      the area below in the graph (if you could zoom it, you could find, that
      there are many different times placed there), so area can hide another.
      
      Blue area corresponds to the port selection optimization.
      
      This is rather simple design approach: hashtable now maintains (unprecise
      and racely updated) number of currently bound sockets, and when number
      of such sockets becomes greater than predefined value (I use maximum
      port range defined by sysctls), we stop traversing the whole bind hash
      table and just stop at first matching bucket after random start. Above
      limit roughly corresponds to the case, when bind hash table is full and
      we turned on mechanism of allowing to bind more reuse-enabled sockets,
      so it does not change behaviour of other sockets.
      Signed-off-by: default avatarEvgeniy Polyakov <zbr@ioremap.net>
      Tested-by: default avatarDenys Fedoryschenko <denys@visp.net.lb>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      a9d8f911
  15. 24 Nov, 2008 1 commit
  16. 23 Nov, 2008 1 commit
    • Eric Dumazet's avatar
      net: Convert TCP/DCCP listening hash tables to use RCU · c25eb3bf
      Eric Dumazet authored
      This is the last step to be able to perform full RCU lookups
      in __inet_lookup() : After established/timewait tables, we
      add RCU lookups to listening hash table.
      
      The only trick here is that a socket of a given type (TCP ipv4,
      TCP ipv6, ...) can now flight between two different tables
      (established and listening) during a RCU grace period, so we
      must use different 'nulls' end-of-chain values for two tables.
      
      We define a large value :
      
      #define LISTENING_NULLS_BASE (1U << 29)
      
      So that slots in listening table are guaranteed to have different
      end-of-chain values than slots in established table. A reader can
      still detect it finished its lookup in the right chain.
      Signed-off-by: default avatarEric Dumazet <dada1@cosmosbay.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c25eb3bf
  17. 20 Nov, 2008 2 commits
  18. 16 Nov, 2008 1 commit
    • Eric Dumazet's avatar
      net: Convert TCP & DCCP hash tables to use RCU / hlist_nulls · 3ab5aee7
      Eric Dumazet authored
      RCU was added to UDP lookups, using a fast infrastructure :
      - sockets kmem_cache use SLAB_DESTROY_BY_RCU and dont pay the
        price of call_rcu() at freeing time.
      - hlist_nulls permits to use few memory barriers.
      
      This patch uses same infrastructure for TCP/DCCP established
      and timewait sockets.
      
      Thanks to SLAB_DESTROY_BY_RCU, no slowdown for applications
      using short lived TCP connections. A followup patch, converting
      rwlocks to spinlocks will even speedup this case.
      
      __inet_lookup_established() is pretty fast now we dont have to
      dirty a contended cache line (read_lock/read_unlock)
      
      Only established and timewait hashtable are converted to RCU
      (bind table and listen table are still using traditional locking)
      Signed-off-by: default avatarEric Dumazet <dada1@cosmosbay.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      3ab5aee7
  19. 12 Nov, 2008 1 commit
  20. 25 Jul, 2008 1 commit
  21. 16 Jul, 2008 1 commit
  22. 16 Jun, 2008 3 commits
  23. 18 Apr, 2008 1 commit
  24. 16 Apr, 2008 1 commit
  25. 31 Mar, 2008 1 commit
  26. 25 Mar, 2008 2 commits
  27. 22 Mar, 2008 1 commit
    • Pavel Emelyanov's avatar
      [SOCK]: Add udp_hash member to struct proto. · 39d8cda7
      Pavel Emelyanov authored
      Inspired by the commit ab1e0a13 ([SOCK] proto: Add hashinfo member to 
      struct proto) from Arnaldo, I made similar thing for UDP/-Lite IPv4 
      and -v6 protocols.
      
      The result is not that exciting, but it removes some levels of
      indirection in udpxxx_get_port and saves some space in code and text.
      
      The first step is to union existing hashinfo and new udp_hash on the
      struct proto and give a name to this union, since future initialization 
      of tcpxxx_prot, dccp_vx_protinfo and udpxxx_protinfo will cause gcc 
      warning about inability to initialize anonymous member this way.
      Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      39d8cda7
  28. 13 Feb, 2008 2 commits
  29. 05 Feb, 2008 1 commit
  30. 03 Feb, 2008 1 commit
    • Arnaldo Carvalho de Melo's avatar
      [SOCK] proto: Add hashinfo member to struct proto · ab1e0a13
      Arnaldo Carvalho de Melo authored
      This way we can remove TCP and DCCP specific versions of
      
      sk->sk_prot->get_port: both v4 and v6 use inet_csk_get_port
      sk->sk_prot->hash:     inet_hash is directly used, only v6 need
                             a specific version to deal with mapped sockets
      sk->sk_prot->unhash:   both v4 and v6 use inet_hash directly
      
      struct inet_connection_sock_af_ops also gets a new member, bind_conflict, so
      that inet_csk_get_port can find the per family routine.
      
      Now only the lookup routines receive as a parameter a struct inet_hashtable.
      
      With this we further reuse code, reducing the difference among INET transport
      protocols.
      
      Eventually work has to be done on UDP and SCTP to make them share this
      infrastructure and get as a bonus inet_diag interfaces so that iproute can be
      used with these protocols.
      
      net-2.6/net/ipv4/inet_hashtables.c:
        struct proto			     |   +8
        struct inet_connection_sock_af_ops |   +8
       2 structs changed
        __inet_hash_nolisten               |  +18
        __inet_hash                        | -210
        inet_put_port                      |   +8
        inet_bind_bucket_create            |   +1
        __inet_hash_connect                |   -8
       5 functions changed, 27 bytes added, 218 bytes removed, diff: -191
      
      net-2.6/net/core/sock.c:
        proto_seq_show                     |   +3
       1 function changed, 3 bytes added, diff: +3
      
      net-2.6/net/ipv4/inet_connection_sock.c:
        inet_csk_get_port                  |  +15
       1 function changed, 15 bytes added, diff: +15
      
      net-2.6/net/ipv4/tcp.c:
        tcp_set_state                      |   -7
       1 function changed, 7 bytes removed, diff: -7
      
      net-2.6/net/ipv4/tcp_ipv4.c:
        tcp_v4_get_port                    |  -31
        tcp_v4_hash                        |  -48
        tcp_v4_destroy_sock                |   -7
        tcp_v4_syn_recv_sock               |   -2
        tcp_unhash                         | -179
       5 functions changed, 267 bytes removed, diff: -267
      
      net-2.6/net/ipv6/inet6_hashtables.c:
        __inet6_hash |   +8
       1 function changed, 8 bytes added, diff: +8
      
      net-2.6/net/ipv4/inet_hashtables.c:
        inet_unhash                        | +190
        inet_hash                          | +242
       2 functions changed, 432 bytes added, diff: +432
      
      vmlinux:
       16 functions changed, 485 bytes added, 492 bytes removed, diff: -7
      
      /home/acme/git/net-2.6/net/ipv6/tcp_ipv6.c:
        tcp_v6_get_port                    |  -31
        tcp_v6_hash                        |   -7
        tcp_v6_syn_recv_sock               |   -9
       3 functions changed, 47 bytes removed, diff: -47
      
      /home/acme/git/net-2.6/net/dccp/proto.c:
        dccp_destroy_sock                  |   -7
        dccp_unhash                        | -179
        dccp_hash                          |  -49
        dccp_set_state                     |   -7
        dccp_done                          |   +1
       5 functions changed, 1 bytes added, 242 bytes removed, diff: -241
      
      /home/acme/git/net-2.6/net/dccp/ipv4.c:
        dccp_v4_get_port                   |  -31
        dccp_v4_request_recv_sock          |   -2
       2 functions changed, 33 bytes removed, diff: -33
      
      /home/acme/git/net-2.6/net/dccp/ipv6.c:
        dccp_v6_get_port                   |  -31
        dccp_v6_hash                       |   -7
        dccp_v6_request_recv_sock          |   +5
       3 functions changed, 5 bytes added, 38 bytes removed, diff: -33
      Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ab1e0a13
  31. 31 Jan, 2008 3 commits
  32. 28 Jan, 2008 1 commit
    • Eric Dumazet's avatar
      [NET]: prot_inuse cleanups and optimizations · 65f76517
      Eric Dumazet authored
      1) Cleanups (all functions are prefixed by sock_prot_inuse)
      
      sock_prot_inc_use(prot) -> sock_prot_inuse_add(prot,-1)
      sock_prot_dec_use(prot) -> sock_prot_inuse_add(prot,-1)
      sock_prot_inuse()       -> sock_prot_inuse_get()
      
      New functions :
      
      sock_prot_inuse_init() and sock_prot_inuse_free() to abstract pcounter use.
      
      2) if CONFIG_PROC_FS=n, we can zap 'inuse' member from "struct proto",
      since nobody wants to read the inuse value.
      
      This saves 1372 bytes on i386/SMP and some cpu cycles.
      Signed-off-by: default avatarEric Dumazet <dada1@cosmosbay.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      65f76517