From 78a478d0efd9e86e5345b436e130497b4e5846e8 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Tue, 26 May 2009 18:50:21 +0000 Subject: [PATCH] gro: Inline skb_gro_header and cache frag0 virtual address The function skb_gro_header is called four times per packet which quickly adds up at 10Gb/s. This patch inlines it to allow better optimisations. Some architectures perform multiplication for page_address, which is done by each skb_gro_header invocation. This patch caches that value in skb->cb to avoid the unnecessary multiplications. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- include/linux/netdevice.h | 22 +++++++++++++++------- net/core/dev.c | 27 ++++++++++++--------------- 2 files changed, 27 insertions(+), 22 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 586b71f..61890ed 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1008,6 +1008,9 @@ void netif_napi_add(struct net_device *dev, struct napi_struct *napi, void netif_napi_del(struct napi_struct *napi); struct napi_gro_cb { + /* Virtual address of skb_shinfo(skb)->frags[0].page + offset. */ + void *frag0; + /* This indicates where we are processing relative to skb->data. */ int data_offset; @@ -1107,9 +1110,9 @@ extern int dev_restart(struct net_device *dev); #ifdef CONFIG_NETPOLL_TRAP extern int netpoll_trap(void); #endif -extern void *skb_gro_header(struct sk_buff *skb, unsigned int hlen); extern int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb); +extern void skb_gro_reset_offset(struct sk_buff *skb); static inline unsigned int skb_gro_offset(const struct sk_buff *skb) { @@ -1126,23 +1129,28 @@ static inline void skb_gro_pull(struct sk_buff *skb, unsigned int len) NAPI_GRO_CB(skb)->data_offset += len; } -static inline void skb_gro_reset_offset(struct sk_buff *skb) +static inline void *skb_gro_header(struct sk_buff *skb, unsigned int hlen) { - NAPI_GRO_CB(skb)->data_offset = 0; + unsigned int offset = skb_gro_offset(skb); + + hlen += offset; + if (!NAPI_GRO_CB(skb)->frag0 || + unlikely(skb_shinfo(skb)->frags[0].size + skb_headlen(skb) < hlen)) + return pskb_may_pull(skb, hlen) ? skb->data + offset : NULL; + + return NAPI_GRO_CB(skb)->frag0 + offset; } static inline void *skb_gro_mac_header(struct sk_buff *skb) { return skb_headlen(skb) ? skb_mac_header(skb) : - page_address(skb_shinfo(skb)->frags[0].page) + - skb_shinfo(skb)->frags[0].page_offset; + NAPI_GRO_CB(skb)->frag0; } static inline void *skb_gro_network_header(struct sk_buff *skb) { return skb_headlen(skb) ? skb_network_header(skb) : - page_address(skb_shinfo(skb)->frags[0].page) + - skb_shinfo(skb)->frags[0].page_offset + skb_network_offset(skb); + NAPI_GRO_CB(skb)->frag0 + skb_network_offset(skb); } static inline int dev_hard_header(struct sk_buff *skb, struct net_device *dev, diff --git a/net/core/dev.c b/net/core/dev.c index 5eb3e48..bdb1a73 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2390,21 +2390,6 @@ void napi_gro_flush(struct napi_struct *napi) } EXPORT_SYMBOL(napi_gro_flush); -void *skb_gro_header(struct sk_buff *skb, unsigned int hlen) -{ - unsigned int offset = skb_gro_offset(skb); - - hlen += offset; - if (unlikely(skb_headlen(skb) || - skb_shinfo(skb)->frags[0].size < hlen || - PageHighMem(skb_shinfo(skb)->frags[0].page))) - return pskb_may_pull(skb, hlen) ? skb->data + offset : NULL; - - return page_address(skb_shinfo(skb)->frags[0].page) + - skb_shinfo(skb)->frags[0].page_offset + offset; -} -EXPORT_SYMBOL(skb_gro_header); - int dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb) { struct sk_buff **pp = NULL; @@ -2520,6 +2505,18 @@ int napi_skb_finish(int ret, struct sk_buff *skb) } EXPORT_SYMBOL(napi_skb_finish); +void skb_gro_reset_offset(struct sk_buff *skb) +{ + NAPI_GRO_CB(skb)->data_offset = 0; + NAPI_GRO_CB(skb)->frag0 = NULL; + + if (!skb_headlen(skb) && !PageHighMem(skb_shinfo(skb)->frags[0].page)) + NAPI_GRO_CB(skb)->frag0 = + page_address(skb_shinfo(skb)->frags[0].page) + + skb_shinfo(skb)->frags[0].page_offset; +} +EXPORT_SYMBOL(skb_gro_reset_offset); + int napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb) { skb_gro_reset_offset(skb); -- 1.8.2.3