• Harald Welte's avatar
    [NETFILTER]: reduce netfilter sk_buff enlargement · 6869c4d8
    Harald Welte authored
    
    
    As discussed at netconf'05, we're trying to save every bit in sk_buff.
    The patch below makes sk_buff 8 bytes smaller.  I did some basic
    testing on my notebook and it seems to work.
    
    The only real in-tree user of nfcache was IPVS, who only needs a
    single bit.  Unfortunately I couldn't find some other free bit in
    sk_buff to stuff that bit into, so I introduced a separate field for
    them.  Maybe the IPVS guys can resolve that to further save space.
    
    Initially I wanted to shrink pkt_type to three bits (PACKET_HOST and
    alike are only 6 values defined), but unfortunately the bluetooth code
    overloads pkt_type :(
    
    The conntrack-event-api (out-of-tree) uses nfcache, but Rusty just
    came up with a way how to do it without any skb fields, so it's safe
    to remove it.
    
    - remove all never-implemented 'nfcache' code
    - don't have ipvs code abuse 'nfcache' field. currently get's their own
      compile-conditional skb->ipvs_property field.  IPVS maintainers can
      decide to move this bit elswhere, but nfcache needs to die.
    - remove skb->nfcache field to save 4 bytes
    - move skb->nfctinfo into three unused bits to save further 4 bytes
    Signed-off-by: default avatarHarald Welte <laforge@netfilter.org>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    6869c4d8
netfilter.h 5.96 KB