Commit d92be7a4 authored Apr 10, 2017 by Alexey Dobriyan Committed by David S. Miller Apr 12, 2017

net: make struct net_device::min_header_len 8-bit



This field is never big enough to warrant 16-bitness.

8-bit accesses enjoy shorted encoding on i386/x86_64 than 16-bit
accesses:

	add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-10 (-10)
	function                                     old     new   delta
	loopback_setup                               169     164      -5
	ether_setup                                  148     143      -5

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 5b3dc2f3

include/linux/netdevice.h

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -1715,7 +1715,7 @@ struct net_device {
	unsigned int max_mtu;		unsigned int max_mtu;
	unsigned short type;		unsigned short type;
	unsigned short hard_header_len;		unsigned short hard_header_len;
	unsigned short min_header_len;		unsigned char min_header_len;

	unsigned short needed_headroom;		unsigned short needed_headroom;
	unsigned short needed_tailroom;		unsigned short needed_tailroom;