net: pack skb_shared_info more efficiently (9f42f126) · Commits · 戴 / test

nr_frags can be 8 bits since 256 is plenty of fragments. This allows it to be packed with tx_flags. Also by moving ip6_frag_id and dataref (both 4 bytes) next to each other we can avoid a hole between ip6_frag_id and frag_list on 64 bit systems. Signed-off-by:

Ian Campbell <ian.campbell@citrix.com> Acked-by:

Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

include/linux/skbuff.h

+3 −3

Original line number	Diff line number	Diff line
		@@ -242,15 +242,15 @@ struct ubuf_info {
		* the end of the header data, ie. at skb->end.
		*/
		struct skb_shared_info {
		unsigned short nr_frags;
		unsigned char nr_frags;
		__u8 tx_flags;
		unsigned short gso_size;
		/* Warning: this field is not always filled in (UFO)! */
		unsigned short gso_segs;
		unsigned short gso_type;
		__be32 ip6_frag_id;
		__u8 tx_flags;
		struct sk_buff *frag_list;
		struct skb_shared_hwtstamps hwtstamps;
		__be32 ip6_frag_id;

		/*
		* Warning : all fields before dataref are cleared in __alloc_skb()

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