[SK_BUFF]: Convert skb->tail to sk_buff_data_t
So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes on 64bit architectures, allowing us to combine the 4 bytes hole left by the layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4 64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN... :-) Many calculations that previously required that skb->{transport,network, mac}_header be first converted to a pointer now can be done directly, being meaningful as offsets or pointers. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:

committed by
David S. Miller

parent
be8bd86321
commit
27a884dc3c
@@ -813,7 +813,7 @@ static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
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{
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struct tcmsg *tcm;
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struct nlmsghdr *nlh;
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unsigned char *b = skb->tail;
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unsigned char *b = skb_tail_pointer(skb);
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struct gnet_dump d;
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nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
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@@ -847,7 +847,7 @@ static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
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if (gnet_stats_finish_copy(&d) < 0)
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goto rtattr_failure;
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nlh->nlmsg_len = skb->tail - b;
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nlh->nlmsg_len = skb_tail_pointer(skb) - b;
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return skb->len;
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nlmsg_failure:
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@@ -1051,7 +1051,7 @@ static int tc_fill_tclass(struct sk_buff *skb, struct Qdisc *q,
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{
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struct tcmsg *tcm;
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struct nlmsghdr *nlh;
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unsigned char *b = skb->tail;
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unsigned char *b = skb_tail_pointer(skb);
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struct gnet_dump d;
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struct Qdisc_class_ops *cl_ops = q->ops->cl_ops;
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@@ -1076,7 +1076,7 @@ static int tc_fill_tclass(struct sk_buff *skb, struct Qdisc *q,
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if (gnet_stats_finish_copy(&d) < 0)
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goto rtattr_failure;
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nlh->nlmsg_len = skb->tail - b;
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nlh->nlmsg_len = skb_tail_pointer(skb) - b;
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return skb->len;
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nlmsg_failure:
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