Re: [PATCH net-next 04/11] tuntap: simplify error handling in tun_build_skb()

[Jason Wang]

On 2018å09æ07æ 22:17, Michael S. Tsirkin wrote:
> On Fri, Sep 07, 2018 at 11:22:00AM +0800, Jason Wang wrote:
> > > > @@ -1668,6 +1668,9 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
> > > >    	if (copied != len)
> > > >    		return ERR_PTR(-EFAULT);
> > > > +	get_page(alloc_frag->page);
> > > > +	alloc_frag->offset += buflen;
> > > > +
> > > This adds an atomic op on XDP_DROP which is a data path
> > > operation for some workloads.
> > Yes, I have patch on top to amortize this, the idea is to have a very big
> > refcount once after the frag was allocated and maintain a bias and decrease
> > them all when allocating new frags.'
> Why bother with refcounting for a drop though? It should be simple.

Right, let me fix this.

Thanks