It is introduced in:
commit 0e3125c755
Author: Neil Horman <nhorman@tuxdriver.com>
Date: Tue Nov 16 10:26:47 2010 -0800
packet: Enhance AF_PACKET implementation to not require high order contiguous memory allocation (v4)
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>