Re: [PATCH net-next v6 3/5] page_pool: Allow drivers to hint on SKB recycling

From: Ilias Apalodimas
Date: Fri Jun 04 2021 - 04:43:30 EST


[...]
> > + /* Driver set this to memory recycling info. Reset it on recycle.
> > + * This will *not* work for NIC using a split-page memory model.
> > + * The page will be returned to the pool here regardless of the
> > + * 'flipped' fragment being in use or not.
> > + */
>
> I am not sure I understand how does the last part of comment related
> to the code below, as there is no driver using split-page memory model
> will reach here because those driver will not call skb_mark_for_recycle(),
> right?
>

Yes the comment is there to prohibit people (mlx5 only actually) to add the
recycling bit on their driver. Because if they do it will *probably* work
but they might get random corrupted packets which will be hard to debug.

> > + page->pp = NULL;
> > + page_pool_put_full_page(pp, virt_to_head_page(data), false);
> > +
> > + return true;
> > +}
> > +EXPORT_SYMBOL(page_pool_return_skb_page);
>