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[NETFILTER]: reduce netfilter sk_buff enlargement

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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: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Harald Welte
2005-08-09 19:24:19 -07:00
committed by David S. Miller
parent bf3a46aa9b
commit 6869c4d8e0
27 changed files with 36 additions and 64 deletions
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2
net/core/skbuff.c
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@ -361,7 +361,6 @@ struct sk_buff *skb_clone(struct sk_buff *skb, unsigned int __nocast gfp_mask)
n->destructor = NULL;
#ifdef CONFIG_NETFILTER
C(nfmark);
C(nfcache);
C(nfct);
nf_conntrack_get(skb->nfct);
C(nfctinfo);
@ -424,7 +423,6 @@ static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
new->destructor = NULL;
#ifdef CONFIG_NETFILTER
new->nfmark = old->nfmark;
new->nfcache = old->nfcache;
new->nfct = old->nfct;
nf_conntrack_get(old->nfct);
new->nfctinfo = old->nfctinfo;