Subject: Re: [bpf-next V2 PATCH 3/8] ixgbe: implement flush flag for ndo_xdp_xmit

From: Jesper Dangaard Brouer <[email-masked]>
Date: Mon, 4 Jun 2018 15:53:24 +0200

On Mon, 4 Jun 2018 15:19:05 +0200
Daniel Borkmann <[email-masked]> wrote:

> > +static void ixgbe_xdp_ring_update_tail(struct ixgbe_ring *ring)
> > +{
> > +	/* Force memory writes to complete before letting h/w know there
> > +	 * are new descriptors to fetch.
> > +	 */
> > +	wmb();
> > +	writel(ring->next_to_use, ring->tail);
> > +}  
> 
> Did you double check that this doesn't become a function call? Should this
> get an __always_inline attribute?

I did check this doesn't become a function call.  The same kind of code
happens other places in the driver, but I choose not to generalize
this, exactly to avoid this becoming a function call ;-)

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer