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  • Arnaldo Carvalho de Melo's avatar
    [INET]: Generalise tcp_tw_bucket, aka TIME_WAIT sockets · 8feaf0c0
    Arnaldo Carvalho de Melo authored
    This paves the way to generalise the rest of the sock ID lookup
    routines and saves some bytes in TCPv4 TIME_WAIT sockets on distro
    kernels (where IPv6 is always built as a module):
    [root@qemu ~]# grep tw_sock /proc/slabinfo
    tw_sock_TCPv6  0  0  128  31  1
    tw_sock_TCP    0  0   96  41  1
    [root@qemu ~]#
    Now if a protocol wants to use the TIME_WAIT generic infrastructure it
    only has to set the sk_prot->twsk_obj_size field with the size of its
    inet_timewait_sock derived sock and proto_register will create
    sk_prot->twsk_slab, for now its only for INET sockets, but we can
    introduce timewait_sock later if some non INET transport protocolo
    wants to use this stuff.
    Next changesets will take advantage of this new infrastructure to
    generalise even more TCP code.
    [acme@toy net-2.6.14]$ grep built-in /tmp/before.size /tmp/after.size
    /tmp/before.size: 188646   11764    5068  205478   322a6 net/ipv4/built-in.o
    /tmp/after.size:  188144   11764    5068  204976   320b0 net/ipv4/built-in.o
    [acme@toy net-2.6.14]$
    Tested with both IPv4 & IPv6 (::1 (localhost) & ::ffff:
    (qemu host)).
    Signed-off-by: default avatarArnaldo Carvalho de Melo <>
    Signed-off-by: default avatarDavid S. Miller <>