net: pack skb_shared_info more efficiently

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>
This commit is contained in:
Ian Campbell 2012-01-05 07:13:39 +00:00 committed by David S. Miller
parent eeca6688d6
commit 9f42f12615

View File

@ -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()