From 27a884dc3cb63b93c2b3b643f5b31eed5f8a4d26 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Thu, 19 Apr 2007 20:29:13 -0700 Subject: [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 Signed-off-by: David S. Miller --- include/linux/skbuff.h | 57 +++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 45 insertions(+), 12 deletions(-) (limited to 'include/linux/skbuff.h') diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 2e740550062..e1c2392ecb5 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -246,9 +246,6 @@ struct sk_buff { int iif; /* 4 byte hole on 64 bit*/ - sk_buff_data_t transport_header; - sk_buff_data_t network_header; - sk_buff_data_t mac_header; struct dst_entry *dst; struct sec_path *sp; @@ -303,13 +300,16 @@ struct sk_buff { __u32 mark; + sk_buff_data_t transport_header; + sk_buff_data_t network_header; + sk_buff_data_t mac_header; /* These elements must be at the end, see alloc_skb() for details. */ - unsigned int truesize; - atomic_t users; + sk_buff_data_t tail; unsigned char *head, *data, - *tail, *end; + unsigned int truesize; + atomic_t users; }; #ifdef __KERNEL__ @@ -812,12 +812,45 @@ static inline void skb_fill_page_desc(struct sk_buff *skb, int i, #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_shinfo(skb)->frag_list) #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb)) +#ifdef NET_SKBUFF_DATA_USES_OFFSET +static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb) +{ + return skb->head + skb->tail; +} + +static inline void skb_reset_tail_pointer(struct sk_buff *skb) +{ + skb->tail = skb->data - skb->head; +} + +static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset) +{ + skb_reset_tail_pointer(skb); + skb->tail += offset; +} +#else /* NET_SKBUFF_DATA_USES_OFFSET */ +static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb) +{ + return skb->tail; +} + +static inline void skb_reset_tail_pointer(struct sk_buff *skb) +{ + skb->tail = skb->data; +} + +static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset) +{ + skb->tail = skb->data + offset; +} +#endif /* NET_SKBUFF_DATA_USES_OFFSET */ + /* * Add data to an sk_buff */ static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len) { - unsigned char *tmp = skb->tail; + unsigned char *tmp = skb_tail_pointer(skb); SKB_LINEAR_ASSERT(skb); skb->tail += len; skb->len += len; @@ -835,11 +868,11 @@ static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len) */ static inline unsigned char *skb_put(struct sk_buff *skb, unsigned int len) { - unsigned char *tmp = skb->tail; + unsigned char *tmp = skb_tail_pointer(skb); SKB_LINEAR_ASSERT(skb); skb->tail += len; skb->len += len; - if (unlikely(skb->tail>skb->end)) + if (unlikely(skb_tail_pointer(skb) > skb->end)) skb_over_panic(skb, len, current_text_addr()); return tmp; } @@ -935,7 +968,7 @@ static inline int skb_headroom(const struct sk_buff *skb) */ static inline int skb_tailroom(const struct sk_buff *skb) { - return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail; + return skb_is_nonlinear(skb) ? 0 : skb->end - skb_tail_pointer(skb); } /** @@ -1127,8 +1160,8 @@ static inline void __skb_trim(struct sk_buff *skb, unsigned int len) WARN_ON(1); return; } - skb->len = len; - skb->tail = skb->data + len; + skb->len = len; + skb_set_tail_pointer(skb, len); } /** -- cgit v1.2.3