1. 04 Apr, 2016 2 commits
  2. 11 Feb, 2016 3 commits
  3. 23 Oct, 2015 1 commit
    • Eric Dumazet's avatar
      tcp/dccp: fix hashdance race for passive sessions · 5e0724d0
      Eric Dumazet authored
      Multiple cpus can process duplicates of incoming ACK messages
      matching a SYN_RECV request socket. This is a rare event under
      normal operations, but definitely can happen.
      
      Only one must win the race, otherwise corruption would occur.
      
      To fix this without adding new atomic ops, we use logic in
      inet_ehash_nolisten() to detect the request was present in the same
      ehash bucket where we try to insert the new child.
      
      If request socket was not found, we have to undo the child creation.
      
      This actually removes a spin_lock()/spin_unlock() pair in
      reqsk_queue_unlink() for the fast path.
      
      Fixes: e994b2f0 ("tcp: do not lock listener to process SYN packets")
      Fixes: 079096f1 ("tcp/dccp: install syn_recv requests into ehash table")
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      5e0724d0
  4. 03 Oct, 2015 1 commit
    • Eric Dumazet's avatar
      tcp/dccp: install syn_recv requests into ehash table · 079096f1
      Eric Dumazet authored
      In this patch, we insert request sockets into TCP/DCCP
      regular ehash table (where ESTABLISHED and TIMEWAIT sockets
      are) instead of using the per listener hash table.
      
      ACK packets find SYN_RECV pseudo sockets without having
      to find and lock the listener.
      
      In nominal conditions, this halves pressure on listener lock.
      
      Note that this will allow for SO_REUSEPORT refinements,
      so that we can select a listener using cpu/numa affinities instead
      of the prior 'consistent hash', since only SYN packets will
      apply this selection logic.
      
      We will shrink listen_sock in the following patch to ease
      code review.
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Cc: Ying Cai <ycai@google.com>
      Cc: Willem de Bruijn <willemb@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      079096f1
  5. 29 Sep, 2015 1 commit
  6. 09 Jul, 2015 1 commit
    • Eric Dumazet's avatar
      inet: simplify timewait refcounting · fc01538f
      Eric Dumazet authored
      timewait sockets have a complex refcounting logic.
      Once we realize it should be similar to established and
      syn_recv sockets, we can use sk_nulls_del_node_init_rcu()
      and remove inet_twsk_unhash()
      
      In particular, deferred inet_twsk_put() added in commit
      13475a30 ("tcp: connect() race with timewait reuse")
      looks unecessary : When removing a timewait socket from
      ehash or bhash, caller must own a reference on the socket
      anyway.
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      fc01538f
  7. 26 May, 2015 1 commit
    • Eric Dumazet's avatar
      tcp: fix/cleanup inet_ehash_locks_alloc() · 095dc8e0
      Eric Dumazet authored
      If tcp ehash table is constrained to a very small number of buckets
      (eg boot parameter thash_entries=128), then we can crash if spinlock
      array has more entries.
      
      While we are at it, un-inline inet_ehash_locks_alloc() and make
      following changes :
      
      - Budget 2 cache lines per cpu worth of 'spinlocks'
      - Try to kmalloc() the array to avoid extra TLB pressure.
        (Most servers at Google allocate 8192 bytes for this hash table)
      - Get rid of various #ifdef
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      095dc8e0
  8. 21 May, 2015 1 commit
  9. 18 Mar, 2015 5 commits
  10. 12 Mar, 2015 1 commit
    • Eric W. Biederman's avatar
      net: Introduce possible_net_t · 0c5c9fb5
      Eric W. Biederman authored
      Having to say
      > #ifdef CONFIG_NET_NS
      > 	struct net *net;
      > #endif
      
      in structures is a little bit wordy and a little bit error prone.
      
      Instead it is possible to say:
      > typedef struct {
      > #ifdef CONFIG_NET_NS
      >       struct net *net;
      > #endif
      > } possible_net_t;
      
      And then in a header say:
      
      > 	possible_net_t net;
      
      Which is cleaner and easier to use and easier to test, as the
      possible_net_t is always there no matter what the compile options.
      
      Further this allows read_pnet and write_pnet to be functions in all
      cases which is better at catching typos.
      
      This change adds possible_net_t, updates the definitions of read_pnet
      and write_pnet, updates optional struct net * variables that
      write_pnet uses on to have the type possible_net_t, and finally fixes
      up the b0rked users of read_pnet and write_pnet.
      Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
      Acked-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      0c5c9fb5
  11. 14 May, 2014 1 commit
  12. 08 Oct, 2013 1 commit
    • Eric Dumazet's avatar
      tcp/dccp: remove twchain · 05dbc7b5
      Eric Dumazet authored
      TCP listener refactoring, part 3 :
      
      Our goal is to hash SYN_RECV sockets into main ehash for fast lookup,
      and parallel SYN processing.
      
      Current inet_ehash_bucket contains two chains, one for ESTABLISH (and
      friend states) sockets, another for TIME_WAIT sockets only.
      
      As the hash table is sized to get at most one socket per bucket, it
      makes little sense to have separate twchain, as it makes the lookup
      slightly more complicated, and doubles hash table memory usage.
      
      If we make sure all socket types have the lookup keys at the same
      offsets, we can use a generic and faster lookup. It turns out TIME_WAIT
      and ESTABLISHED sockets already have common lookup fields for IPv4.
      
      [ INET_TW_MATCH() is no longer needed ]
      
      I'll provide a follow-up to factorize IPv6 lookup as well, to remove
      INET6_TW_MATCH()
      
      This way, SYN_RECV pseudo sockets will be supported the same.
      
      A new sock_gen_put() helper is added, doing either a sock_put() or
      inet_twsk_put() [ and will support SYN_RECV later ].
      
      Note this helper should only be called in real slow path, when rcu
      lookup found a socket that was moved to another identity (freed/reused
      immediately), but could eventually be used in other contexts, like
      sock_edemux()
      
      Before patch :
      
      dmesg | grep "TCP established"
      
      TCP established hash table entries: 524288 (order: 11, 8388608 bytes)
      
      After patch :
      
      TCP established hash table entries: 524288 (order: 10, 4194304 bytes)
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      05dbc7b5
  13. 03 Oct, 2013 1 commit
    • Eric Dumazet's avatar
      inet: consolidate INET_TW_MATCH · 50805466
      Eric Dumazet authored
      TCP listener refactoring, part 2 :
      
      We can use a generic lookup, sockets being in whatever state, if
      we are sure all relevant fields are at the same place in all socket
      types (ESTABLISH, TIME_WAIT, SYN_RECV)
      
      This patch removes these macros :
      
       inet_addrpair, inet_addrpair, tw_addrpair, tw_portpair
      
      And adds :
      
       sk_portpair, sk_addrpair, sk_daddr, sk_rcv_saddr
      
      Then, INET_TW_MATCH() is really the same than INET_MATCH()
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      50805466
  14. 21 Sep, 2013 1 commit
  15. 27 Feb, 2013 1 commit
    • Sasha Levin's avatar
      hlist: drop the node parameter from iterators · b67bfe0d
      Sasha Levin authored
      I'm not sure why, but the hlist for each entry iterators were conceived
      
              list_for_each_entry(pos, head, member)
      
      The hlist ones were greedy and wanted an extra parameter:
      
              hlist_for_each_entry(tpos, pos, head, member)
      
      Why did they need an extra pos parameter? I'm not quite sure. Not only
      they don't really need it, it also prevents the iterator from looking
      exactly like the list iterator, which is unfortunate.
      
      Besides the semantic patch, there was some manual work required:
      
       - Fix up the actual hlist iterators in linux/list.h
       - Fix up the declaration of other iterators based on the hlist ones.
       - A very small amount of places were using the 'node' parameter, this
       was modified to use 'obj->member' instead.
       - Coccinelle didn't handle the hlist_for_each_entry_safe iterator
       properly, so those had to be fixed up manually.
      
      The semantic patch which is mostly the work of Peter Senna Tschudin is here:
      
      @@
      iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;
      
      type T;
      expression a,c,d,e;
      identifier b;
      statement S;
      @@
      
      -T b;
          <+... when != b
      (
      hlist_for_each_entry(a,
      - b,
      c, d) S
      |
      hlist_for_each_entry_continue(a,
      - b,
      c) S
      |
      hlist_for_each_entry_from(a,
      - b,
      c) S
      |
      hlist_for_each_entry_rcu(a,
      - b,
      c, d) S
      |
      hlist_for_each_entry_rcu_bh(a,
      - b,
      c, d) S
      |
      hlist_for_each_entry_continue_rcu_bh(a,
      - b,
      c) S
      |
      for_each_busy_worker(a, c,
      - b,
      d) S
      |
      ax25_uid_for_each(a,
      - b,
      c) S
      |
      ax25_for_each(a,
      - b,
      c) S
      |
      inet_bind_bucket_for_each(a,
      - b,
      c) S
      |
      sctp_for_each_hentry(a,
      - b,
      c) S
      |
      sk_for_each(a,
      - b,
      c) S
      |
      sk_for_each_rcu(a,
      - b,
      c) S
      |
      sk_for_each_from
      -(a, b)
      +(a)
      S
      + sk_for_each_from(a) S
      |
      sk_for_each_safe(a,
      - b,
      c, d) S
      |
      sk_for_each_bound(a,
      - b,
      c) S
      |
      hlist_for_each_entry_safe(a,
      - b,
      c, d, e) S
      |
      hlist_for_each_entry_continue_rcu(a,
      - b,
      c) S
      |
      nr_neigh_for_each(a,
      - b,
      c) S
      |
      nr_neigh_for_each_safe(a,
      - b,
      c, d) S
      |
      nr_node_for_each(a,
      - b,
      c) S
      |
      nr_node_for_each_safe(a,
      - b,
      c, d) S
      |
      - for_each_gfn_sp(a, c, d, b) S
      + for_each_gfn_sp(a, c, d) S
      |
      - for_each_gfn_indirect_valid_sp(a, c, d, b) S
      + for_each_gfn_indirect_valid_sp(a, c, d) S
      |
      for_each_host(a,
      - b,
      c) S
      |
      for_each_host_safe(a,
      - b,
      c, d) S
      |
      for_each_mesh_entry(a,
      - b,
      c, d) S
      )
          ...+>
      
      [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
      [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
      [akpm@linux-foundation.org: checkpatch fixes]
      [akpm@linux-foundation.org: fix warnings]
      [akpm@linux-foudnation.org: redo intrusive kvm changes]
      Tested-by: default avatarPeter Senna Tschudin <peter.senna@gmail.com>
      Acked-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Cc: Wu Fengguang <fengguang.wu@intel.com>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Cc: Gleb Natapov <gleb@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b67bfe0d
  16. 23 Jan, 2013 1 commit
    • Tom Herbert's avatar
      soreuseport: TCP/IPv4 implementation · da5e3630
      Tom Herbert authored
      Allow multiple listener sockets to bind to the same port.
      
      Motivation for soresuseport would be something like a web server
      binding to port 80 running with multiple threads, where each thread
      might have it's own listener socket.  This could be done as an
      alternative to other models: 1) have one listener thread which
      dispatches completed connections to workers. 2) accept on a single
      listener socket from multiple threads.  In case #1 the listener thread
      can easily become the bottleneck with high connection turn-over rate.
      In case #2, the proportion of connections accepted per thread tends
      to be uneven under high connection load (assuming simple event loop:
      while (1) { accept(); process() }, wakeup does not promote fairness
      among the sockets.  We have seen the  disproportion to be as high
      as 3:1 ratio between thread accepting most connections and the one
      accepting the fewest.  With so_reusport the distribution is
      uniform.
      Signed-off-by: default avatarTom Herbert <therbert@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      da5e3630
  17. 02 Dec, 2012 1 commit
  18. 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
  19. 19 Jun, 2012 1 commit
    • David S. Miller's avatar
      ipv4: Early TCP socket demux. · 41063e9d
      David S. Miller authored
      Input packet processing for local sockets involves two major demuxes.
      One for the route and one for the socket.
      
      But we can optimize this down to one demux for certain kinds of local
      sockets.
      
      Currently we only do this for established TCP sockets, but it could
      at least in theory be expanded to other kinds of connections.
      
      If a TCP socket is established then it's identity is fully specified.
      
      This means that whatever input route was used during the three-way
      handshake must work equally well for the rest of the connection since
      the keys will not change.
      
      Once we move to established state, we cache the receive packet's input
      route to use later.
      
      Like the existing cached route in sk->sk_dst_cache used for output
      packets, we have to check for route invalidations using dst->obsolete
      and dst->ops->check().
      
      Early demux occurs outside of a socket locked section, so when a route
      invalidation occurs we defer the fixup of sk->sk_rx_dst until we are
      actually inside of established state packet processing and thus have
      the socket locked.
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      41063e9d
  20. 26 Jul, 2011 1 commit
  21. 21 Oct, 2010 1 commit
  22. 08 Dec, 2009 1 commit
  23. 13 Nov, 2009 1 commit
  24. 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
  25. 13 Oct, 2009 1 commit
  26. 03 Jun, 2009 1 commit
  27. 01 Feb, 2009 1 commit
  28. 27 Jan, 2009 1 commit
    • Eric Dumazet's avatar
      net: wrong test in inet_ehash_locks_alloc() · 94cd3e6c
      Eric Dumazet authored
      In commit 9db66bdc (net: convert
      TCP/DCCP ehash rwlocks to spinlocks), I forgot to change one
      occurrence of rwlock_t to spinlock_t
      
      I believe sizeof(raw_spinlock_t) might be > 0 on !CONFIG_SMP if
      CONFIG_DEBUG_SPINLOCK while sizeof(raw_rwlock_t) should be 0 in this
      case.
      
      Fortunatly, CONFIG_DEBUG_SPINLOCK adds fields to both spinlock_t and
      rwlock_t, but at this might change in the future (being able to debug
      spinlocks but not rwlocks for example), better to be safe.
      Signed-off-by: default avatarEric Dumazet <dada1@cosmosbay.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      94cd3e6c
  29. 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
  30. 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
  31. 21 Nov, 2008 1 commit
  32. 20 Nov, 2008 2 commits