diff options
author | Eric Dumazet <edumazet@google.com> | 2014-09-28 22:18:47 -0700 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2014-09-29 12:27:20 -0400 |
commit | b1937227316417aa7568d01e6fa1f272e98fb890 (patch) | |
tree | 93891f7672c803b767de6621c028f45edf242f17 /include | |
parent | 842abe08aa6f81f1062cf9624e9f6afc117d73e4 (diff) | |
download | linux-b1937227316417aa7568d01e6fa1f272e98fb890.tar.bz2 |
net: reorganize sk_buff for faster __copy_skb_header()
With proliferation of bit fields in sk_buff, __copy_skb_header() became
quite expensive, showing as the most expensive function in a GSO
workload.
__copy_skb_header() performance is also critical for non GSO TCP
operations, as it is used from skb_clone()
This patch carefully moves all the fields that were not copied in a
separate zone : cloned, nohdr, fclone, peeked, head_frag, xmit_more
Then I moved all other fields and all other copied fields in a section
delimited by headers_start[0]/headers_end[0] section so that we
can use a single memcpy() call, inlined by compiler using long
word load/stores.
I also tried to make all copies in the natural orders of sk_buff,
to help hardware prefetching.
I made sure sk_buff size did not change.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/skbuff.h | 133 |
1 files changed, 72 insertions, 61 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 8eaa62400fca..b6cced304b26 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -527,27 +527,41 @@ struct sk_buff { char cb[48] __aligned(8); unsigned long _skb_refdst; + void (*destructor)(struct sk_buff *skb); #ifdef CONFIG_XFRM struct sec_path *sp; #endif +#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) + struct nf_conntrack *nfct; +#endif +#ifdef CONFIG_BRIDGE_NETFILTER + struct nf_bridge_info *nf_bridge; +#endif unsigned int len, data_len; __u16 mac_len, hdr_len; - union { - __wsum csum; - struct { - __u16 csum_start; - __u16 csum_offset; - }; - }; - __u32 priority; + + /* Following fields are _not_ copied in __copy_skb_header() + * Note that queue_mapping is here mostly to fill a hole. + */ kmemcheck_bitfield_begin(flags1); - __u8 ignore_df:1, - cloned:1, - ip_summed:2, + __u16 queue_mapping; + __u8 cloned:1, nohdr:1, - nfctinfo:3; + fclone:2, + peeked:1, + head_frag:1, + xmit_more:1; + /* one bit hole */ + kmemcheck_bitfield_end(flags1); + + + + /* fields enclosed in headers_start/headers_end are copied + * using a single memcpy() in __copy_skb_header() + */ + __u32 headers_start[0]; /* if you move pkt_type around you also must adapt those constants */ #ifdef __BIG_ENDIAN_BITFIELD @@ -558,58 +572,53 @@ struct sk_buff { #define PKT_TYPE_OFFSET() offsetof(struct sk_buff, __pkt_type_offset) __u8 __pkt_type_offset[0]; - __u8 pkt_type:3, - fclone:2, - ipvs_property:1, - peeked:1, - nf_trace:1; - kmemcheck_bitfield_end(flags1); - __be16 protocol; - - void (*destructor)(struct sk_buff *skb); -#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) - struct nf_conntrack *nfct; -#endif -#ifdef CONFIG_BRIDGE_NETFILTER - struct nf_bridge_info *nf_bridge; -#endif - - int skb_iif; - - __u32 hash; - - __be16 vlan_proto; - __u16 vlan_tci; - -#ifdef CONFIG_NET_SCHED - __u16 tc_index; /* traffic control index */ -#ifdef CONFIG_NET_CLS_ACT - __u16 tc_verd; /* traffic control verdict */ -#endif -#endif - - __u16 queue_mapping; - kmemcheck_bitfield_begin(flags2); - __u8 xmit_more:1; -#ifdef CONFIG_IPV6_NDISC_NODETYPE - __u8 ndisc_nodetype:2; -#endif + __u8 pkt_type:3; __u8 pfmemalloc:1; + __u8 ignore_df:1; + __u8 nfctinfo:3; + + __u8 nf_trace:1; + __u8 ip_summed:2; __u8 ooo_okay:1; __u8 l4_hash:1; __u8 sw_hash:1; __u8 wifi_acked_valid:1; __u8 wifi_acked:1; + __u8 no_fcs:1; - __u8 head_frag:1; /* Indicates the inner headers are valid in the skbuff. */ __u8 encapsulation:1; __u8 encap_hdr_csum:1; __u8 csum_valid:1; __u8 csum_complete_sw:1; - /* 1/3 bit hole (depending on ndisc_nodetype presence) */ - kmemcheck_bitfield_end(flags2); + __u8 csum_level:2; + __u8 csum_bad:1; +#ifdef CONFIG_IPV6_NDISC_NODETYPE + __u8 ndisc_nodetype:2; +#endif + __u8 ipvs_property:1; + /* 5 or 7 bit hole */ + +#ifdef CONFIG_NET_SCHED + __u16 tc_index; /* traffic control index */ +#ifdef CONFIG_NET_CLS_ACT + __u16 tc_verd; /* traffic control verdict */ +#endif +#endif + + union { + __wsum csum; + struct { + __u16 csum_start; + __u16 csum_offset; + }; + }; + __u32 priority; + int skb_iif; + __u32 hash; + __be16 vlan_proto; + __u16 vlan_tci; #if defined CONFIG_NET_DMA || defined CONFIG_NET_RX_BUSY_POLL union { unsigned int napi_id; @@ -625,19 +634,18 @@ struct sk_buff { __u32 reserved_tailroom; }; - kmemcheck_bitfield_begin(flags3); - __u8 csum_level:2; - __u8 csum_bad:1; - /* 13 bit hole */ - kmemcheck_bitfield_end(flags3); - __be16 inner_protocol; __u16 inner_transport_header; __u16 inner_network_header; __u16 inner_mac_header; + + __be16 protocol; __u16 transport_header; __u16 network_header; __u16 mac_header; + + __u32 headers_end[0]; + /* These elements must be at the end, see alloc_skb() for details. */ sk_buff_data_t tail; sk_buff_data_t end; @@ -3040,19 +3048,22 @@ static inline void nf_reset_trace(struct sk_buff *skb) } /* Note: This doesn't put any conntrack and bridge info in dst. */ -static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src) +static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src, + bool copy) { #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) dst->nfct = src->nfct; nf_conntrack_get(src->nfct); - dst->nfctinfo = src->nfctinfo; + if (copy) + dst->nfctinfo = src->nfctinfo; #endif #ifdef CONFIG_BRIDGE_NETFILTER dst->nf_bridge = src->nf_bridge; nf_bridge_get(src->nf_bridge); #endif #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES) - dst->nf_trace = src->nf_trace; + if (copy) + dst->nf_trace = src->nf_trace; #endif } @@ -3064,7 +3075,7 @@ static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src) #ifdef CONFIG_BRIDGE_NETFILTER nf_bridge_put(dst->nf_bridge); #endif - __nf_copy(dst, src); + __nf_copy(dst, src, true); } #ifdef CONFIG_NETWORK_SECMARK |