On Wed, Oct 28, 2020 at 11:23:04AM +0100, Lorenzo Bianconi wrote:
> > Hi Lorenzo,
>
> Hi Ilias,
>
> thx for the review.
>
> >
> > On Tue, Oct 27, 2020 at 08:04:07PM +0100, Lorenzo Bianconi wrote:
>
> [...]
>
> > > +void xdp_return_frame_bulk(struct xdp_frame *xdpf,
> > > + struct xdp_frame_bulk *bq)
> > > +{
> > > + struct xdp_mem_info *mem = &xdpf->mem;
> > > + struct xdp_mem_allocator *xa, *nxa;
> > > +
> > > + if (mem->type != MEM_TYPE_PAGE_POOL) {
> > > + __xdp_return(xdpf->data, &xdpf->mem, false);
> > > + return;
> > > + }
> > > +
> > > + rcu_read_lock();
> > > +
> > > + xa = bq->xa;
> > > + if (unlikely(!xa || mem->id != xa->mem.id)) {
> >
> > Why is this marked as unlikely? The driver passes it as NULL. Should unlikely be
> > checked on both xa and the comparison?
>
> xa is NULL only for the first xdp_frame in the burst while it is set for
> subsequent ones. Do you think it is better to remove it?
Ah correct, missed the general context of the driver this runs in.
>
> >
> > > + nxa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
> >
> > Is there a chance nxa can be NULL?
>
> I do not think so since the page_pool is not destroyed while there are
> in-flight pages, right?
I think so but I am not 100% sure. I'll apply the patch and have a closer look
Cheers
/Ilias
