skbuff: micro-optimize {,__}skb_header_pointer()
{,__}skb_header_pointer() helpers exist mainly for preventing accesses-beyond-end of the linear data. In the vast majorify of cases, they bail out on the first condition. All code going after is mostly a fallback. Mark the most common branch as 'likely' one to move it in-line. Also, skb_copy_bits() can return negative values only when the input arguments are invalid, e.g. offset is greater than skb->len. It can be safely marked as 'unlikely' branch, assuming that hotpath code provides sane input to not fail here. These two bump the throughput with a single Flow Dissector pass on every packet (e.g. with RPS or driver that uses eth_get_headlen()) on 20 Mbps per flow/core. Signed-off-by:Alexander Lobakin <alobakin@pm.me> Signed-off-by:
David S. Miller <davem@davemloft.net>
parent
59753ce8
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