From: Saeed Mahameed > Sent: 31 January 2017 20:59 > Cache skb_vlan_tag_present(skb) and pass it wherever needed in xmit > routines. ...
Does this actually generate better code?
It is quite likely that your 'vlan_present' variable ends up being on stack.
Whereas the 'skb' is likely to be in a register.
In which case the two loads are likely to be must the same and your
change has added a write to the stack.
David
