1. 12 Oct, 2015 1 commit
    • Eric Dumazet's avatar
      net: align sk_refcnt on 128 bytes boundary · 8e5eb54d
      Eric Dumazet authored
      sk->sk_refcnt is dirtied for every TCP/UDP incoming packet.
      This is a performance issue if multiple cpus hit a common socket,
      or multiple sockets are chained due to SO_REUSEPORT.
      By moving sk_refcnt 8 bytes further, first 128 bytes of sockets
      are mostly read. As they contain the lookup keys, this has
      a considerable performance impact, as cpus can cache them.
      These 8 bytes are not wasted, we use them as a place holder
      for various fields, depending on the socket type.
       SYN flood hitting a 16 RX queues NIC.
       TCP listener using 16 sockets and SO_REUSEPORT
       and SO_INCOMING_CPU for proper siloing.
       Could process 6.0 Mpps SYN instead of 4.2 Mpps
       Kernel profile looked like :
          11.68%  [kernel]  [k] sha_transform
           6.51%  [kernel]  [k] __inet_lookup_listener
           5.07%  [kernel]  [k] __inet_lookup_established
           4.15%  [kernel]  [k] memcpy_erms
           3.46%  [kernel]  [k] ipt_do_table
           2.74%  [kernel]  [k] fib_table_lookup
           2.54%  [kernel]  [k] tcp_make_synack
           2.34%  [kernel]  [k] tcp_conn_request
           2.05%  [kernel]  [k] __netif_receive_skb_core
           2.03%  [kernel]  [k] kmem_cache_alloc
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
  2. 21 Sep, 2015 1 commit
    • Eric Dumazet's avatar
      tcp/dccp: fix timewait races in timer handling · ed2e9239
      Eric Dumazet authored
      When creating a timewait socket, we need to arm the timer before
      allowing other cpus to find it. The signal allowing cpus to find
      the socket is setting tw_refcnt to non zero value.
      As we set tw_refcnt in __inet_twsk_hashdance(), we therefore need to
      call inet_twsk_schedule() first.
      This also means we need to remove tw_refcnt changes from
      inet_twsk_schedule() and let the caller handle it.
      Note that because we use mod_timer_pinned(), we have the guarantee
      the timer wont expire before we set tw_refcnt as we run in BH context.
      To make things more readable I introduced inet_twsk_reschedule() helper.
      When rearming the timer, we can use mod_timer_pending() to make sure
      we do not rearm a canceled timer.
      Note: This bug can possibly trigger if packets of a flow can hit
      multiple cpus. This does not normally happen, unless flow steering
      is broken somehow. This explains this bug was spotted ~5 months after
      its introduction.
      A similar fix is needed for SYN_RECV sockets in reqsk_queue_hash_req(),
      but will be provided in a separate patch for proper tracking.
      Fixes: 789f558c ("tcp/dccp: get rid of central timewait timer")
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Reported-by: default avatarYing Cai <ycai@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
  3. 09 Jul, 2015 2 commits
  4. 13 Apr, 2015 1 commit
    • Eric Dumazet's avatar
      tcp/dccp: get rid of central timewait timer · 789f558c
      Eric Dumazet authored
      Using a timer wheel for timewait sockets was nice ~15 years ago when
      memory was expensive and machines had a single processor.
      This does not scale, code is ugly and source of huge latencies
      (Typically 30 ms have been seen, cpus spinning on death_lock spinlock.)
      We can afford to use an extra 64 bytes per timewait sock and spread
      timewait load to all cpus to have better behavior.
      On following test, /proc/sys/net/ipv4/tcp_tw_recycle is set to 1
      on the target (lpaa24)
      Before patch :
      lpaa23:~# ./super_netperf 200 -H lpaa24 -t TCP_CC -l 60 -- -p0,0
      lpaa23:~# ./super_netperf 200 -H lpaa24 -t TCP_CC -l 60 -- -p0,0
      While test is running, we can observe 25 or even 33 ms latencies.
      lpaa24:~# ping -c 1000 -i 0.02 -qn lpaa23
      1000 packets transmitted, 1000 received, 0% packet loss, time 20601ms
      rtt min/avg/max/mdev = 0.020/0.217/25.771/1.535 ms, pipe 2
      lpaa24:~# ping -c 1000 -i 0.02 -qn lpaa23
      1000 packets transmitted, 1000 received, 0% packet loss, time 20702ms
      rtt min/avg/max/mdev = 0.019/0.183/33.761/1.441 ms, pipe 2
      After patch :
      About 90% increase of throughput :
      lpaa23:~# ./super_netperf 200 -H lpaa24 -t TCP_CC -l 60 -- -p0,0
      lpaa23:~# ./super_netperf 200 -H lpaa24 -t TCP_CC -l 60 -- -p0,0
      And latencies are kept to minimal values during this load, even
      if network utilization is 90% higher :
      lpaa24:~# ping -c 1000 -i 0.02 -qn lpaa23
      1000 packets transmitted, 1000 received, 0% packet loss, time 19991ms
      rtt min/avg/max/mdev = 0.023/0.064/0.360/0.042 ms
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
  5. 11 Mar, 2015 1 commit
    • Eric Dumazet's avatar
      net: add real socket cookies · 33cf7c90
      Eric Dumazet authored
      A long standing problem in netlink socket dumps is the use
      of kernel socket addresses as cookies.
      1) It is a security concern.
      2) Sockets can be reused quite quickly, so there is
         no guarantee a cookie is used once and identify
         a flow.
      3) request sock, establish sock, and timewait socks
         for a given flow have different cookies.
      Part of our effort to bring better TCP statistics requires
      to switch to a different allocator.
      In this patch, I chose to use a per network namespace 64bit generator,
      and to use it only in the case a socket needs to be dumped to netlink.
      (This might be refined later if needed)
      Note that I tried to carry cookies from request sock, to establish sock,
      then timewait sockets.
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Cc: Eric Salo <salo@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
  6. 02 Jul, 2014 1 commit
    • Eric Dumazet's avatar
      inet: move ipv6only in sock_common · 9fe516ba
      Eric Dumazet authored
      When an UDP application switches from AF_INET to AF_INET6 sockets, we
      have a small performance degradation for IPv4 communications because of
      extra cache line misses to access ipv6only information.
      This can also be noticed for TCP listeners, as ipv6_only_sock() is also
      used from __inet_lookup_listener()->compute_score()
      This is magnified when SO_REUSEPORT is used.
      Move ipv6only into struct sock_common so that it is available at
      no extra cost in lookups.
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
  7. 17 Jan, 2014 1 commit
  8. 17 Oct, 2013 1 commit
  9. 08 Oct, 2013 2 commits
    • Eric Dumazet's avatar
      ipv6: make lookups simpler and faster · efe4208f
      Eric Dumazet authored
      TCP listener refactoring, part 4 :
      To speed up inet lookups, we moved IPv4 addresses from inet to struct
      Now is time to do the same for IPv6, because it permits us to have fast
      lookups for all kind of sockets, including upcoming SYN_RECV.
      Getting IPv6 addresses in TCP lookups currently requires two extra cache
      lines, plus a dereference (and memory stall).
      inet6_sk(sk) does the dereference of inet_sk(__sk)->pinet6
      This patch is way bigger than its IPv4 counter part, because for IPv4,
      we could add aliases (inet_daddr, inet_rcv_saddr), while on IPv6,
      it's not doable easily.
      inet6_sk(sk)->daddr becomes sk->sk_v6_daddr
      inet6_sk(sk)->rcv_saddr becomes sk->sk_v6_rcv_saddr
      And timewait socket also have tw->tw_v6_daddr & tw->tw_v6_rcv_saddr
      at the same offset.
      We get rid of INET6_TW_MATCH() as INET6_MATCH() is now the generic
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    • 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
      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
      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>
  10. 03 Oct, 2013 2 commits
    • Eric Dumazet's avatar
      tcp: shrink tcp6_timewait_sock by one cache line · 96f817fe
      Eric Dumazet authored
      While working on tcp listener refactoring, I found that it
      would really make things easier if sock_common could include
      the IPv6 addresses needed in the lookups, instead of doing
      very complex games to get their values (depending on sock
      For this to happen, I need to be sure that tcp6_timewait_sock
      and tcp_timewait_sock consume same number of cache lines.
      This is possible if we only use 32bits for tw_ttd, as we remove
      one 32bit hole in inet_timewait_sock
      inet_tw_time_stamp() is defined and used, even if its current
      implementation looks like tcp_time_stamp : We might need finer
      resolution for tcp_time_stamp in the future.
      Before patch : sizeof(struct tcp6_timewait_sock) = 0xc8
      After patch : sizeof(struct tcp6_timewait_sock) = 0xc0
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    • 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
      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>
  11. 21 Sep, 2013 1 commit
  12. 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
      - b,
      c, d) S
      - b,
      c) S
      - b,
      c) S
      - b,
      c, d) S
      - b,
      c, d) S
      - b,
      c) S
      for_each_busy_worker(a, c,
      - b,
      d) S
      - b,
      c) S
      - b,
      c) S
      - b,
      c) S
      - b,
      c) S
      - b,
      c) S
      - b,
      c) S
      -(a, b)
      + sk_for_each_from(a) S
      - b,
      c, d) S
      - b,
      c) S
      - b,
      c, d, e) S
      - b,
      c) S
      - b,
      c) S
      - b,
      c, d) S
      - b,
      c) S
      - 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
      - b,
      c) S
      - b,
      c, d) S
      - 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>
  13. 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>
  14. 14 Dec, 2011 1 commit
  15. 31 Oct, 2011 1 commit
  16. 26 Oct, 2011 1 commit
  17. 24 Oct, 2011 1 commit
    • Eric Dumazet's avatar
      ipv4: tcp: fix TOS value in ACK messages sent from TIME_WAIT · 66b13d99
      Eric Dumazet authored
      There is a long standing bug in linux tcp stack, about ACK messages sent
      on behalf of TIME_WAIT sockets.
      In the IP header of the ACK message, we choose to reflect TOS field of
      incoming message, and this might break some setups.
      Example of things that were broken :
        - Routing using TOS as a selector
        - Firewalls
        - Trafic classification / shaping
      We now remember in timewait structure the inet tos field and use it in
      ACK generation, and route lookup.
      Notes :
       - We still reflect incoming TOS in RST messages.
       - We could extend MuraliRaja Muniraju patch to report TOS value in
      netlink messages for TIME_WAIT sockets.
       - A patch is needed for IPv6
      Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
  18. 26 Jul, 2011 1 commit
  19. 09 Dec, 2010 1 commit
    • Eric Dumazet's avatar
      net: optimize INET input path further · 68835aba
      Eric Dumazet authored
      Followup of commit b178bb3d (net: reorder struct sock fields)
      Optimize INET input path a bit further, by :
      1) moving sk_refcnt close to sk_lock.
      This reduces number of dirtied cache lines by one on 64bit arches (and
      64 bytes cache line size).
      2) moving inet_daddr & inet_rcv_saddr at the beginning of sk
      (same cache line than hash / family / bound_dev_if / nulls_node)
      This reduces number of accessed cache lines in lookups by one, and dont
      increase size of inet and timewait socks.
      inet and tw sockets now share same place-holder for these fields.
      Before patch :
      offsetof(struct sock, sk_refcnt) = 0x10
      offsetof(struct sock, sk_lock) = 0x40
      offsetof(struct sock, sk_receive_queue) = 0x60
      offsetof(struct inet_sock, inet_daddr) = 0x270
      offsetof(struct inet_sock, inet_rcv_saddr) = 0x274
      After patch :
      offsetof(struct sock, sk_refcnt) = 0x44
      offsetof(struct sock, sk_lock) = 0x48
      offsetof(struct sock, sk_receive_queue) = 0x68
      offsetof(struct inet_sock, inet_daddr) = 0x0
      offsetof(struct inet_sock, inet_rcv_saddr) = 0x4
      compute_score() (udp or tcp) now use a single cache line per ignored
      item, instead of two.
      Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
  20. 27 Apr, 2010 1 commit
  21. 08 Dec, 2009 1 commit
  22. 03 Dec, 2009 2 commits
    • 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
      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>
    • Eric W. Biederman's avatar
      net: Batch inet_twsk_purge · b099ce26
      Eric W. Biederman authored
      This function walks the whole hashtable so there is no point in
      passing it a network namespace.  Instead I purge all timewait
      sockets from dead network namespaces that I find.  If the namespace
      is one of the once I am trying to purge I am guaranteed no new timewait
      sockets can be formed so this will get them all.  If the namespace
      is one I am not acting for it might form a few more but I will
      call inet_twsk_purge again and  shortly to get rid of them.  In
      any even if the network namespace is dead timewait sockets are
      Move the calls of inet_twsk_purge into batch_exit routines so
      that if I am killing a bunch of namespaces at once I will just
      call inet_twsk_purge once and save a lot of redundant unnecessary
      My simple 4k network namespace exit test the cleanup time dropped from
      roughly 8.2s to 1.6s.  While the time spent running inet_twsk_purge fell
      to about 2ms.  1ms for ipv4 and 1ms for ipv6.
      Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
  23. 20 Oct, 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>
  25. 15 Jun, 2009 1 commit
  26. 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>
  27. 01 Oct, 2008 1 commit
  28. 08 Sep, 2008 1 commit
    • Daniel Lezcano's avatar
      netns : fix kernel panic in timewait socket destruction · d315492b
      Daniel Lezcano authored
      How to reproduce ?
       - create a network namespace
       - use tcp protocol and get timewait socket
       - exit the network namespace
       - after a moment (when the timewait socket is destroyed), the kernel
      # BUG: unable to handle kernel NULL pointer dereference at
      IP: [<ffffffff821e394d>] inet_twdr_do_twkill_work+0x6e/0xb8
      PGD 119985067 PUD 11c5c0067 PMD 0
      Oops: 0000 [1] SMP
      CPU 1
      Modules linked in: ipv6 button battery ac loop dm_mod tg3 libphy ext3 jbd
      edd fan thermal processor thermal_sys sg sata_svw libata dock serverworks
      sd_mod scsi_mod ide_disk ide_core [last unloaded: freq_table]
      Pid: 0, comm: swapper Not tainted 2.6.27-rc2 #3
      RIP: 0010:[<ffffffff821e394d>] [<ffffffff821e394d>]
      RSP: 0018:ffff88011ff7fed0 EFLAGS: 00010246
      RAX: ffffffffffffffff RBX: ffffffff82339420 RCX: ffff88011ff7ff30
      RDX: 0000000000000001 RSI: ffff88011a4d03c0 RDI: ffff88011ac2fc00
      RBP: ffffffff823392e0 R08: 0000000000000000 R09: ffff88002802a200
      R10: ffff8800a5c4b000 R11: ffffffff823e4080 R12: ffff88011ac2fc00
      R13: 0000000000000001 R14: 0000000000000001 R15: 0000000000000000
      FS: 0000000041cbd940(0000) GS:ffff8800bff839c0(0000)
      CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
      CR2: 0000000000000007 CR3: 00000000bd87c000 CR4: 00000000000006e0
      DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
      DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
      Process swapper (pid: 0, threadinfo ffff8800bff9e000, task
      Stack: ffffffff823392e0 0000000000000100 ffffffff821e3a3a
      0000000000000000 ffffffff821e3a61 ffff8800bff7c000 ffffffff8203c7e7
      ffff88011ff7ff10 ffff88011ff7ff10 0000000000000021 ffffffff82351108
      Call Trace:
      <IRQ> [<ffffffff821e3a3a>] ? inet_twdr_hangman+0x0/0x9e
      [<ffffffff821e3a61>] ? inet_twdr_hangman+0x27/0x9e
      [<ffffffff8203c7e7>] ? run_timer_softirq+0x12c/0x193
      [<ffffffff820390d1>] ? __do_softirq+0x5e/0xcd
      [<ffffffff8200d08c>] ? call_softirq+0x1c/0x28
      [<ffffffff8200e611>] ? do_softirq+0x2c/0x68
      [<ffffffff8201a055>] ? smp_apic_timer_interrupt+0x8e/0xa9
      [<ffffffff8200cad6>] ? apic_timer_interrupt+0x66/0x70
      <EOI> [<ffffffff82011f4c>] ? default_idle+0x27/0x3b
      [<ffffffff8200abbd>] ? cpu_idle+0x5f/0x7d
      Code: e8 01 00 00 4c 89 e7 41 ff c5 e8 8d fd ff ff 49 8b 44 24 38 4c 89 e7
      65 8b 14 25 24 00 00 00 89 d2 48 8b 80 e8 00 00 00 48 f7 d0 <48> 8b 04 d0
      48 ff 40 58 e8 fc fc ff ff 48 89 df e8 c0 5f 04 00
      RIP [<ffffffff821e394d>] inet_twdr_do_twkill_work+0x6e/0xb8
      RSP <ffff88011ff7fed0>
      CR2: 0000000000000007
      This patch provides a function to purge all timewait sockets related
      to a network namespace. The timewait sockets life cycle is not tied with
      the network namespace, that means the timewait sockets stay alive while
      the network namespace dies. The timewait sockets are for avoiding to
      receive a duplicate packet from the network, if the network namespace is
      freed, the network stack is removed, so no chance to receive any packets
      from the outside world. Furthermore, having a pending destruction timer
      on these sockets with a network namespace freed is not safe and will lead
      to an oops if the timer callback which try to access data belonging to 
      the namespace like for example in:
      		-> NET_INC_STATS_BH(twsk_net(tw), LINUX_MIB_TIMEWAITED);
      Purging the timewait sockets at the network namespace destruction will:
       1) speed up memory freeing for the namespace
       2) fix kernel panic on asynchronous timewait destruction
      Signed-off-by: default avatarDaniel Lezcano <dlezcano@fr.ibm.com>
      Acked-by: default avatarDenis V. Lunev <den@openvz.org>
      Acked-by: default avatarEric W. Biederman <ebiederm@xmission.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
  29. 26 Mar, 2008 1 commit
  30. 25 Mar, 2008 1 commit
  31. 03 Feb, 2008 1 commit
  32. 28 Jan, 2008 1 commit
    • Pavel Emelyanov's avatar
      [INET]: Uninline the inet_twsk_put function. · 7054fb93
      Pavel Emelyanov authored
      This one is not that big, but is widely used: saves 1200 bytes
      from net/ipv4/built-in.o
      add/remove: 1/0 grow/shrink: 1/12 up/down: 97/-1300 (-1203)
      function                                     old     new   delta
      inet_twsk_put                                  -      87     +87
      __inet_lookup_listener                       274     284     +10
      tcp_sacktag_write_queue                     2255    2254      -1
      tcp_time_wait                                482     411     -71
      __inet_check_established                     796     722     -74
      tcp_v4_err                                   973     898     -75
      __inet_twsk_kill                             230     154     -76
      inet_twsk_deschedule                         180     103     -77
      tcp_v4_do_rcv                                462     384     -78
      inet_hash_connect                            686     607     -79
      inet_twdr_do_twkill_work                     236     150     -86
      inet_twdr_twcal_tick                         395     307     -88
      tcp_v4_rcv                                  1744    1480    -264
      tcp_timewait_state_process                   975     644    -331
      Export it for ipv6 module.
      Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
  33. 10 Oct, 2007 1 commit
  34. 14 Jul, 2007 1 commit
  35. 05 Mar, 2007 1 commit
  36. 22 Nov, 2006 1 commit
    • David Howells's avatar
      WorkStruct: Pass the work_struct pointer instead of context data · 65f27f38
      David Howells authored
      Pass the work_struct pointer to the work function rather than context data.
      The work function can use container_of() to work out the data.
      For the cases where the container of the work_struct may go away the moment the
      pending bit is cleared, it is made possible to defer the release of the
      structure by deferring the clearing of the pending bit.
      To make this work, an extra flag is introduced into the management side of the
      work_struct.  This governs auto-release of the structure upon execution.
      Ordinarily, the work queue executor would release the work_struct for further
      scheduling or deallocation by clearing the pending bit prior to jumping to the
      work function.  This means that, unless the driver makes some guarantee itself
      that the work_struct won't go away, the work function may not access anything
      else in the work_struct or its container lest they be deallocated..  This is a
      problem if the auxiliary data is taken away (as done by the last patch).
      However, if the pending bit is *not* cleared before jumping to the work
      function, then the work function *may* access the work_struct and its container
      with no problems.  But then the work function must itself release the
      work_struct by calling work_release().
      In most cases, automatic release is fine, so this is the default.  Special
      initiators exist for the non-auto-release case (ending in _NAR).
      Signed-Off-By: default avatarDavid Howells <dhowells@redhat.com>