> On Tue, 27 Oct 2020 20:04:07 +0100
> Lorenzo Bianconi <lorenzo@xxxxxxxxxx> wrote:
>
> > diff --git a/net/core/xdp.c b/net/core/xdp.c
> > index 48aba933a5a8..93eabd789246 100644
> > --- a/net/core/xdp.c
> > +++ b/net/core/xdp.c
> > @@ -380,6 +380,57 @@ void xdp_return_frame_rx_napi(struct xdp_frame *xdpf)
> > }
> > EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
> >
> > +void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq)
> > +{
> > + struct xdp_mem_allocator *xa = bq->xa;
> > + int i;
> > +
> > + if (unlikely(!xa))
> > + return;
> > +
> > + for (i = 0; i < bq->count; i++) {
> > + struct page *page = virt_to_head_page(bq->q[i]);
> > +
> > + page_pool_put_full_page(xa->page_pool, page, false);
> > + }
> > + bq->count = 0;
> > +}
> > +EXPORT_SYMBOL_GPL(xdp_flush_frame_bulk);
> > +
> > +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)) {
> > + nxa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
> > + if (unlikely(!xa)) {
> > + bq->count = 0;
> > + bq->xa = nxa;
> > + xa = nxa;
> > + }
> > + }
> > +
> > + if (mem->id != xa->mem.id || bq->count == XDP_BULK_QUEUE_SIZE)
> > + xdp_flush_frame_bulk(bq);
> > +
> > + bq->q[bq->count++] = xdpf->data;
> > + if (mem->id != xa->mem.id)
> > + bq->xa = nxa;
> > +
> > + rcu_read_unlock();
> > +}
> > +EXPORT_SYMBOL_GPL(xdp_return_frame_bulk);
>
> We (Ilias my co-maintainer and I) think above code is hard to read and
> understand (as a reader you need to keep too many cases in your head).
>
> I think we both have proposals to improve this, here is mine:
>
> /* Defers return when frame belongs to same mem.id as previous frame */
> 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;
>
> if (mem->type != MEM_TYPE_PAGE_POOL) {
> __xdp_return(xdpf->data, &xdpf->mem, false);
> return;
> }
>
> rcu_read_lock();
>
> xa = bq->xa;
> if (unlikely(!xa)) {
> xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
> bq->count = 0;
> bq->xa = xa;
> }
>
> if (bq->count == XDP_BULK_QUEUE_SIZE)
> xdp_flush_frame_bulk(bq);
>
> if (mem->id != xa->mem.id) {
> xdp_flush_frame_bulk(bq);
> bq->xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
> }
>
> bq->q[bq->count++] = xdpf->data;
>
> rcu_read_unlock();
> }
>
> Please review for correctness, and also for readability.
the code seems fine to me (and even easier to read :)).
I will update v2 using this approach. Thx.
Regards,
Lorenzo
>
> --
> Best regards,
> Jesper Dangaard Brouer
> MSc.CS, Principal Kernel Engineer at Red Hat
> LinkedIn: http://www.linkedin.com/in/brouer
>
Attachment:
signature.asc
Description: PGP signature
